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Editor-in-Chief: Paolo RussoPast Editor-in-Chief: Fridtjof
Nsslin
PhysicaMedicaEuropean Journal of Medical PhysicsThe official
journal of the
Associazione Italiana di Fisica Medica,European Federation of
Organizations for Medical Physics,Irish Association of Physicists
in Medicine andSocit Franaise de Physique Mdicale
Abstracts from the 8th European Conference on Medical
Physics
September 11th13th, 2014Athens, Greece
1.2671.849
Volume 30 Issue S1 September 2014 ISSN 1120-1797
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Under the Auspices and Support of the Greek National Tourism
Organisation
Abstracts from the 8th European Conference on Medical
Physics
September 11th13th, 2014Athens, Greece
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8 Invited Lectures
Oral Presentations 23
E-Posters with presentation
E-Posters 82
52
Physica Medica:European Journal of Medical Physics
Volume 30, Supplement 1, 2014
The official journal of the European Federation of Organizations
for Medical Physics, Associazione Italiana di Fisica Medica, Socit
Franaise de Physique Mdicale
and Irish Association of Physicists in MedicinePhysica Medica is
recognised by the European Physical Society
CONTENTS
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Le
the large and increasing number of procedures and the large
involve-ment of professionals outside the radiology department have
partiallyimpaired these efforts with the results, as demonstrated
by recentstudies, that the practice in general has not yet reached
acceptableoptimisation levels.For patient exposures, national and
international surveys are showinglarge variations in the practice,
n the performance of radiological equip-ment, in the technical
protocols and, nally, in the patient doses. The
of half yearly tests.Every day, the centres make 2 acquisitions
of a ho-mogenous test object that is rotated over 180 between the 2
exposures.Raw data are sent to a DICOM receiver program, analysed
and sent to theQC platform of our centre (product of qaelum NV,
Belgium). The centrestest also the monitors with a variable test
pattern, that shows every daydifferent low contrast characters to
allow the testing of the characteristicsof monitor and reading
room. The same platform (qaelum NV, Belgium) isused for quality
supervision.
lab
M
/ /w
Physica Medica 30S1 (2014)(IR) and cardiology (IC) practice is
the objective of more than 20 years ofnational and international
studies, recommendations and actions. But,
During the lecture we will show the software networking platform
fordaily QC supervision and the link between these daily data and
the resultsInvited
PATIENT DOSE AND IMAGE QUALITY: ROLE OF MEDICAL PHYSICISTS
Francis R. Verdun. Institute of Radiation Physics (IRA), CHUV,
Lausanne,Switzerland
Introduction: Radiation protection in medicine is becoming a
real chal-lenge when dealing with the use of technologies such as
CT, uoroscopyand PET/CT. In Switzerland, since January 2012,
medical physicists have tobe involved with the medical team dealing
with high dose proceduressuch as the ones mentioned above to
strengthen the optimization process.This new role for medical
physicists has a strong potential in the frame-work of medical
radiation protection. The aim of this presentation is toshow, using
a few examples, how the introduction of this new legalrequirement
can improve radiation protection not only of the patient butalso of
the staff.Material and Method: Our Institute is in charge of
consulting more thantwenty-ve centers (50 CT units; 10 uoroscopy
units used for interven-tional radiology and cardiology and 5
PET/CT units). These units have beenmonitored using common
protocols that, while integrating some standardquality assurance
measurements, mainly focus on the way the unit is usedin
practice.Results: A wide variation of protocols is applied for
comparable in-dications. For example, patient doses for a standard
abdominal CT exam-ination can vary by a factor of 23. Cumulative
doses over 5 Gy can be verycommon in some centers without taking
any special measures to informthe patient of the possibility to
develop tissue reactions. To improve thepresent situation, several
measures should be introduced: standardizationof the CT protocols
nomenclature, standardization of the interventionalprocedures
names, and denition of clinically relevant image
qualitylevels.Conclusion: The implication of medical physicists in
radiology and nu-clear medicine has the potential to improve the
optimization of radio-logical procedures. As opposed to radiation
therapy, precision in dosemeasurements should not be the main role
of medical physicists. She/heshould part of the medical team to
improve the standardization of theexaminations or procedures
nomenclature and to develop a strategy toprovide the physician with
clinically relevant measures of image quality.Then one could work
on the balance between diagnostic information andrisk.
DOSE REDUCTION IN INTERVENTIONAL RADIOLOGY & CARDIOLOGY
Renato Padovani. ICTP Abdus Salam Int. Centre for Theoretical
Physics,Trieste, Italy
Optimisation of patient and staff exposure in interventional
radiology
Contents lists avai
Physica
journal homepage: http:ctures
optimization instrument of the DRLs, assessed only for few
procedures andmainly for IC, is rarely implemented and used. The
ICRP is putting newefforts in redening the methods to assess and
use DRLs as a tool to limitnon acceptable dose levels and helping
in the optimization process.For staff exposure, ISEMIR project has
highlighted a poor monitoringpractice in IC bringing to important
underestimation of doses and, newchallenges for eye lens dosimetry
are coming from the 2011 ICRP state-ment recommending a new and
lower eye lens dose limit. Staff moni-toring, aiming to assure the
compliance with the dose limits, is in generalaffected by large
uncertainties for staff exposed near the radiation sourceand
partially protected. These uncertainties are larger for lens
eyedosimetry for the use of protective glasses and for the
laterality and thefrom-below direction of the irradiation. These
large uncertainties, whenthe doses are of the same order of
magnitude of the limit as happen foreyes, are not assuring the
compliance with the new dose limit. As anexample of advanced
dosimetry, the active dosimetry technology canimprove staff
monitoring providing instant information on exposures,allowing the
integration of staff and patient exposure data and,
nally,supporting staff education.To progress in the staff
optimization it will be necessary to advance indosimetry methods,
harmonise dosimetry practice, to develop interna-tional databases
to support benchmarking, promote optimized procedureprotocols, and
require harmonized and certied education and training.
QA IN DIGITAL MAMMOGRAPHY: LOCAL ACTIVITIES AND
REMOTECONTROL
Hilde Bosmans. KU Leuven, Department of Imaging and pathology,
Belgium
Quality assurance in mammography should ensure the optimal
balancebetween X-ray dose and image quality. The European
Guidelines on QA inmammography include a protocol for digital
mammography equipmentthat allows to evaluate the X-ray tube,
detector, settings of the automaticexposure control, the monitor
and overall image quality. There are no in-dications as to how
assure the quality of the clinical image quality. Theprotocol
recommends that daily or weekly quality control tests should
becentrally supervised.Our regional government has required to
perform breast cancer screeningin line with the chapter on
physico-technical tests. To do so, we imple-mented yearly and half
yearly tests for digital mammography and dailytests of the X-ray
system and the monitors. AQ new X-ray modality has topass a type
test procedure rst. Seen the large number of mammographysystems in
our region, the daily and weekly procedures have been
largelyautomated.We have contracts for QA activities on 103
mammography units, includingCR and DR systems of all major vendors
and 3 more lm-screen systems.
le at ScienceDirect
edica
ww.physicamedica.com
-
Medica 30S1 (2014)Recently, 2 scientic papers have conrmed good
performance of ourscreening program. These studies are also a
conrmation for the group ofphysicists who have worked at a strict
physic-technical quality assurancesystem. The networking approach
could be copied in other countries ofcourse. Session number of
session in which the abstract is presented: Scienticsession: QA in
radiology; Thursday afternoon, 14.30 e 15.30 Session title of
session in which the abstract is presented
FULLY AUTOMATED TREATMENT PLAN GENERATION IN DAILY ROUTINE
B. Heijmen, P. Voet, M. Dirkx, A. Sharfo, L. Rossi, D. Fransen,
J. Penninkhof,M. Hoogeman, S. Petit, J.-W. Mens, A. Mendez Romero,
A. Al-Mamgani, L.Incrocci, S. Breedveld. Erasmus MC Cancer
Institute, Rotterdam, TheNetherlands
Background: Currently, treatment plans are generated by
dosimetristsusing a trial-and-error procedure. The process may take
several hours andplan quality is dependent on the skills and
experience of the dosimetrist,and on allotted time. We have
developed and clinically introduced a sys-tem for fully automatic
plan generation, using lexicographic multi-criterialoptimization to
replace the labour-intensive and operator-dependent trial-and-error
approach.Materials and Methods: For each patient, the treatment
plan is fullyautomatically generated by the clinical treatment
planning system(Monaco, Elekta AB), based on a patient-specic
template that is auto-matically pre-generated with our in-house
lexicographic multi-criterialoptimizer (Erasmus-iCycle, Med Phys.
2012; 39(2): 951). Automatic plangeneration in Erasmus-iCycle is
based on a wishlist with hard constraintsand treatment objectives
with assigned priorities. For each treatment site(e.g. H&N
cancer), a single xed wish-list is used for all patients. In case
ofIMRT, Erasmus-iCycle can be used for integrated beam prole
optimizationand (non-coplanar) beam angle selection.Results: In a
prospective clinical H&N cancer study, radiation
oncologistsselected the AUTO-plan in 97% of cases rather than the
MANUAL-plangenerated by trial-and-error (IJROBP 2013; 85(3):
866-72). For a group of44 cervical cancer patients, dual-arc VMAT
AUTO-plans were superior toMANUAL-plans generated by an expert
cervical cancer planner, spendingmany hours; reduced small bowel
V15Gy, V45Gy, and Dmean, bladder Dmean,and rectum Dmean, p
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Abstracts / Physica Medica 30S1 (2014) 3concept of lateral
buildup ratio (LBR) as an avenue to evaluate electronlater scatter
equilibrium and compute dose per MU for those elds. Finally,it
gives some common clinical examples where electron beam
dosimetryare applied.This presentation will try to provide guidance
to the audience for betterunderstanding the methods and
recommendations in TG-70. In addition,will describe how to link the
absolute dose calibration recommendationsof TG-51 to the relative
dose measurements of TG-71.
TOWARDS DAILY ADAPTED PROTON THERAPY
Tony Lomax. Centre for Proton Therapy, Paul Scherrer Institute,
Switzerland
Proton therapy using Pencil Beam Scanning (PBS) is a highly
conformal andexible form of radiotherapy. However, anatomic changes
of the patientduring the course of therapy are a major challenge
due to the potentiallymajor changes in proton ranges that can
result. The challenge is evengreater given that such changes can
occur on a daily basis and currentsoftware systems and workows in
radiotherapy are too slow to react tosuch changes. In order to
fully exploit the highly conformal characteristicsof PBS proton
therapy therefore, methods for the daily adaption of protontherapy
need to be developed, a concept we call Daily Adaptive
ProtonTherapy (DAPT). The concept of DAPT is to work towards a
exible andfully automated workow for PBS proton therapy, with the
aim of imaging,planning and delivering a plan-of-the-day for
patients on a daily basis. Inorder to achieve this, the time
between the imaging of the patient anddelivery of the plan has to
be reduced to a maximum of 1-2 minutes. Withthe in-room imaging
capabilities of the PSI Gantry 2, and the inherentexibility of PBS
proton therapy, we believe we already have the idealtreatment
machine for the implementation of DAPT. However, the chal-lenges
are more computational and workow oriented than technological.In
order tomove towards a DAPTapproach for instance, image
registration,planning and optimisation procedures must be made
computationallyefcient and fully automated. In addition, efcient
and informative toolsneed to be developed that will allow clinical
staff to review these plans-of-the-day, as well as to allow for
fast, but nevertheless safe, quality assur-ance checks of the
plans. For instance, with the introduction of DAPT typeapproaches,
it will be impossible to perform patient or eld specicdosimetric
verications, and other, automated methods for checking thedelity of
treatments and treatment control les will need to be devel-oped.
Thus, there are many challenges to be met before DAPT will becomea
reality. However, we rmly believe that moving in this direction is
thenext major advance in clinical proton therapy, and its
introduction couldhave at least as large an impact on current
clinical practice with protons asthe introduction of Intensity
Modulated Proton Therapy. Indeed, one couldargue that PBS proton
therapy, with its exible and automatedworkow, ispre-destined for
the DAPT concept.
FLUORESCENT NUCLEAR TRACK DETECTORS AS A TOOL FOR
ION-BEAMTHERAPY RESEARCH
S. Greilich a, O. Jakel a,b,c. aGerman Cancer Research Center
(DKFZ), Divisionof Medical Physics in Radiation Oncology, Im
Neuenheimer Feld 280, 69120Heidelberg, Germany; bHeidelberg
University Hospital, Department ofRadiation Oncology, Im
Neuenheimer Feld 400, 69120 Heidelberg,Germany; cHeidelberg
Ion-Beam Therapy Center (HIT), Im NeuenheimerFeld 450, 69120
Heidelberg, Germany
Originally designed for optical storage, uorescent nuclear track
detectors(FNTD) based on Al2O3:C,Mg single crystals contain
aggregate F2
2+(2 Mg)color centers that show permanent radiochromic
transformation whenbombarded with ionizing radiation. Transformed
centers produce highyield uorescence at 750 nmwhen stimulated at
620 nm and a short (755ns) lifetime. This enables non-destructive
readout using confocal laser-scanning microscopes (CLSMs, Akselrod
and Sykora, 2011). Since the in-tensity signal depends on the local
energy deposition, 3D particle trajec-tories through the crystal
can be assessed. Together with the excellentsensitivity Al2O3:C,Mg
this enables the derivation of information on tracklocation,
direction, energy loss, etc. over the entire particle and
energyrange found in ion beam therapy. Effects such as projectile
fragmentationand secondary electron trajectories can be studied in
detail with diffrac-tion-limited resolution (Greilich et al.,
2013). Due to their biocompatibility,autoclavability and since
post-irradiation chemical processing is notneeded, FNTDs can show
signicant superiority to existing technologiessuch as plastic
nuclear track detectors (PNTDs, e.g. CR-39).Our group studies the
FNTD technology for application on three mainelds: Fundamental
dosimetry quantities (w-value, I-value) in ion beams:FNTDs allow
determining particle uence and range with very high ac-curacy
(Osinga et al., 2013, Klimpki et al., 2013). In-vivo track-based
assessment of dose to organs at risk during therapy:FNTDs represent
one of a few systems that enable biological dose esti-mation which
is the essential predictor for clinical outcome in ion beamtherapy.
In addition, FNTD are small, resilient, wireless and
biocompatibleand can be therefore used within phantoms, animal
models or evenpatients. Radiobiology: our group was the rst to use
FNTDs as substrate for cell(Cell-Fit-HD, Niklas et al., 2013). This
enables to correlate microscopicphysical parameters and
subcellular/cell response both in xed and livingcell and study
cellular processes fundamental to ion beam radiotherapythat are
hitherto little understood.The talk will present the basic
principle of FNTD technology, our groupstechnical implementation as
well as the latest methodological de-velopments and application
results.References1. Akselrod MS, Sykora GJ: Fluorescent nuclear
track detector technologyeA new way to do passive solid state
dosimetry. Radiat Meas 2011,46:1671e1679.2. Greilich S, Osinga J-M,
Niklas M, Lauer FM, Klimpki G, Bestvater F, BartzJA, Akselrod MS,
Jakel O: Fluorescent Nuclear Track Detectors as a Tool forIon-Beam
Therapy Research. Radiat Meas 2013, 56:267e272.3. Klimpki G, Osinga
J-M, Herrmann R, Akselrod MS, Jakel O, Greilich S: IonRange
Measurements using Fluorescent Nuclear Track Detectors. RadiatMeas
2013, 56:342e346.4. Niklas M, Abdollahi A, Akselrod MS, Debus J,
Jakel O, Greilich S: Sub-cellular spatial correlation of particle
traversal and biological response inclinical ion beams. Int J
Radiat Oncol 2013, 87:1141e1147.5. Osinga J-M, Brons S, Bartz J a,
Akselrod MS, Jakel O, Greilich S: AbsorbedDose in Ion Beams:
Comparison of Ionisation- and Fluence-Based Mea-surements. Radiat
Prot Dosimetry 2014.
INCREASING PRECISION IN PARTICLE THERAPY: IN VIVO DOSIMETRYAND
BEYOND
C. Richter a,b,c,d, G. Pausch a,b,d, J. Seco e, T. Bortfeld e,
W.Enghardt a,b,c,d. aOncoRay e National Center for Radiation
Research inOncology, Faculty of Medicine and University Hospital
C.G. Carus,Technische Universitat Dresden, Germany; bDepartment of
RadiationOncology, Faculty of Medicine and University Hospital C.G.
Carus,Technische Universitat Dresden, Germany; cGerman Cancer
Consortium(DKTK), Dresden, & German Cancer Research Center
(DKFZ), Heidelberg,Germany; dHelmholtz-Zentrum Dresden-Rossendorf,
Germany;eMassachusetts General Hospital and Harvard Medical School,
Departmentof Radiation Oncology, Boston, MA, USA
The proton dose distribution including the steep dose gradient
at the endof range not only allows a better sparing of normal
tissue. It also enforcesthe need of a precise control of the dose
deposition to ensure the correctposition of the dose gradient to
take full advantage of the superior capa-bilities of proton
therapy. Otherwise, factors like tissue heterogeneities,patient
positioning errors and intra-fractional motion can cause high
un-certainties in proton distal range resulting in a failing tumor
coverage or/and an unnecessary high dose deposition in healthy
tissue due to the use ofextended margins. Therefore, an in vivo
verication or any other control ofproton range and delivered dose
distribution is highly desirable.Several in vivo dosimetry
approaches will be presented and compared.They rely on either
nuclear interactions of the beam with the irradiatedmatter (In
beam-PET and prompt g-ray imaging) or on the visualization of
-
Abstracts / Physica Medica 30S1 (2014)4biological processes
induced by radiation, e.g. with MRI. The most expe-rience exists
for in beam-PET. In Dresden, the current research focuses
ontime-resolved acquisition (4D-PET) and on automated detection of
rangedeviations. In contrast, prompt gamma ray imaging is a
relatively new anddynamic eld of research. Several prompt g-ray
imaging detector systemsare under development in various research
centers around the worldbased on active- as well as passively
collimated systems. A complementaryapproach, based on the time
spectrum of the g-ray emission, is investi-gated in Dresden. First
promising results will be presented in the talk.However, so far
there is no clinical application of prompt g-ray based invivo
dosimetry. In contrast, radiation-induced biological changes
havebeen used in clinical trials at the Massachusetts General
Hospital in Boston(MGH) for range verication in both, spine and
liver. A recent study, alsocarried out at MGH, aims at a better
understanding of when those treat-ment related changes in the liver
begin to appear.Instead of assuring a safe and precise treatment by
measuring the in vivodose deposition, another approach is to
decrease dose deposition un-certainties before beam delivery. This
can be done in several ways: Oneapproach tries to increase the
robustness of the treatment plan againstdifferent types of
uncertainties. This can be realized by including therobustness in
the optimization and penalizing treatment plans with a
dosedeposition very prone to expected deviations. A completely
differentmethod for increasing dose deposition precision is based
on online im-aging during treatment: If the exact patient geometry
would be known forevery time point, the delivered dose deposition
could be calculated andeven adapted online if necessary. Online
imaging could be performed withMRI scanners integrated in the
treatment room in analogy to the combinedMRI-linac approaches. At
the moment this is a eld of intense researchwith quite impressing
progress.At this point it is not clear which of the different
methods to increaseprecision in particle therapy will nd their way
in routine clinical appli-cation. Nevertheless, the demand and the
potential of these methods areunquestionable.
MONTE CARLO MODELING AND IMAGE-GUIDANCE IN PARTICLETHERAPY
G. Dedes, K. Parodi. Department of Medical Physics, Ludwig
MaximiliansUniversity, Munich, Germany
The use of protons and heavier ions in external beam therapy
offersdistinctive advantages with respect to conventional
radiotherapy usingelectromagnetic radiation. The physical
selectivity of ions with the char-acteristic Bragg curve can enable
high tumor-dose conformity, resulting inlower irradiation of
healthy tissues and critical organs in close vicinity tothe target
volume. Moreover, the higher
relative-biological-effectiveness(RBE), especially in the case of
heavier ions, can offer improved controlprobability for
radioresistant tumors. In this context, Monte Carlo (MC)particle
transport and interaction methods are increasingly employed
inclinical and research institutions as vital tools to support
several aspects ofbeam modeling, treatment planning and quality
assurance of high preci-sion ion beam therapy.This talk will review
the role of MC methods in selected applications inparticle therapy.
Drawing on own experience at different European particletherapy
facilities, the ne tuning of MC parameters for beammodeling willbe
presented. In addition, based on ongoing studies and
collaborations, wewill give an overview on thewide range of MC
applications aiming at noveltools for image guidance and treatment
planning. These include the sup-port to the development of heavy
ion and proton computed tomography,as well as the direct usage of
MC-data in the inverse planning process,featuring calculations of
both absorbed and biologically weighted dose.Development and
validation of new solutions based on clinically estab-lished
imaging modalities for adaptive strategies in particle therapy will
bealso addressed, together with research efforts to support
unconventionalimaging-based techniques detecting secondary
radiation for in-vivoconrmation of the actual treatment delivery.
Finally, the application ofMonte Carlo tools in the emerging
research area of laser driven ion ac-celeration for medical
application will be briey exposed.Parts of this work have been
supported by the DFG Cluster of Excellence
MAP (Munich-Centre for Advanced Photonics), the DFG Project on
IonRadiography and Tomography, the FP7 Project ENVISION, and the
BMBFProject SPARTA.
IMAGE GUIDANCE FOR ADAPTIVE RADIOTHERAPY: IS THERE STILL ANEED
FOR SURROGATE SYSTEMS?
Torsten Moser. Im Neuenheimer Feld 280, 69120, Heidelberg,
Germany
In conformal radiation therapy, accurate and reproducible
patient setup isrequired. In this regard, initial setup errors, as
well as day-to-day setupvariation, still poses a clinically
relevant problem. The available anatomic(internal) information of
the patient, however, relies on the images of theplanning CT,
acquired up to weeks prior to treatment and does not reectchanges
during the actual treatment. To correct in the actual situation,
themost reliable information is obtained by 3D-imaging techniques
like conebeam CT. Adaptive treatment techniques, moreover, adds a
furthercomponent to the treatment chain, the feed-back. Again by
daily imageguidance, changes that occur during the treatment can be
detected andhandled. Meanwhile, most linear accelerators are able
to acquire images(eg, kilovoltage/megavoltage setup images or cone
beam computed to-mography [CT] scans) that allow correlation of the
actual patient positionwith that during treatment planning CT. By
the use of such image guidedradiation therapy techniques, the
potential benet for the patient has to beweighed against the
additional risk associated with the imaging dose.For this reason,
non-radiologic techniques to verify the setup position ofthe
patient are of great interest. As such developments, there are
varioussystems available that provide also information of motion
and/or position.There are devices available where electromagnetic
markers have to beimplanted into the patient or technologies where
other informations areused to generate signals that can be used for
position or motion correction.One of the latter are optical surface
imaging systems. Optical surface im-aging systems are able to
reconstruct a 3-dimensional (3D) surface modelrelative to the
isocenter position. A setup correction is calculated byregistering
actual images with reference images stored in the system
be-forehand. Although the technical accuracy of such systems has
been shownto be quite high, their suitability for clinical
application depends onadditional aspects, in particular on a xed
spatial relation between thesurface and target region. To analyze
this, setup corrections from a surfaceimaging systemwere evaluated
in 120 patients. As a measure of reliability,the corrections
derived by the optical system were compared with thosefrom 3D
radiologic imaging, which is the current gold standard in
imageguided radiation therapy. We found a dependence on the target
region andthe used reference image modality. Therefore, additional
radiologic im-aging may still be necessary on a regular basis
(e.g., weekly) or if thecorrections of the optical system appear
implausibly large. Nevertheless,such a combined application may
help to reduce the imaging dose for thepatient.
SMALL PHOTON FIELD DOSIMETRY: PRESENT STATUS
Maria M. Aspradakis. Cantonal Hospital of Lucerne, 6000 Lucerne
16,Switzerland
Background: IPEM report 1031 summarised existing knowledge on
thephysics and challenges in the dosimetry of small MV photon
elds,reviewed available detectors for dose measurement, gave
recommenda-tions based on existing knowledge and experience,
explained the need ofcommissioning treatment planning systems for
small eld applicationsand pointed out directions for future work.
This presentation reports onrecent developments.Materials and
Methods: A megavoltage (MV) photon eld is dened assmall when either
the eld size is not large enough to provide lateralcharged particle
equilibrium at the point of dose measurement or thecollimating
device obstructs part of the focal spot as viewed from thatpoint.
The overlapping penubras from opposing jaws result that the
fullwidth half maximum of the dose prole (FWHM) no longer matches
thecollimator setting. Thus, the conventional dention of eld size
in terms ofFWHM breaks down. The measurement of dosimetric
paraments in suchnon-at narrow elds becomes a challenge because
most detectors are too
large to resolve the non at dose prole or that they perturb
uence in a
-
a Meway that using available perturbation factors is not
appropriate. Further-more, changes in energy spectrum with eld
size, the fact that on somemodern radiotherapy equipment
conventional reference conditionscannot be realised or that the
attening lter is not present, means thatcurrent dosimetry codes of
practice do not provide recommendations fordosimetry in such
elds.Results & Discussion: The new formalism for dose
determination in smalland non-standard photon elds developed by the
IAEA/AAPM isexplained2. Some results on detector-specic beam
quality correctionsfactors are presented.References1. Aspradakis,
M.M., Byrne, J. P., Palmans, H., Conway, J., Rosser, K.,
War-rington, A. P., Duane, S. IPEM report 103: 'Small Field MV
Photon Dosimetry'.2010, York, UK: Institute of Physics and
Engineering in Medicine (IPEM).ISBN 978 1 903613 45 02. Palmans, H,
Dosimetry of small elds: Present status and future guidelinesby
IAEA, Radiotherapy & Oncology, Vol 111, Supp 1, April 2014,
ISSN 0167-8140
MEDICAL PHYSICS CHALLENGES WITHIN THE MICROBEAM RADIATIONTHERAPY
(MRT) PROJECT
E. Brauer-Krisch a,f, C. Nemoz a,f, T. Brochard a,f, M. Renier
a,f, H.Requardt a,f, R. Serduc b,f, G. LeDuc a,f, A. Bravin a,f, S.
Bartzsch c,f, P.Fournier d,a,f, I. Cornelius d,f, P. Berkvens a,f,
J.C. Crosbie d,f, M.L.F.Lerch d,f, A.B. Rosenfeld d,f, M. Donzelli
a,c,f, U.Oelfke c,f, A. Bouchet e,f, H.Blattmann g,f, B. Kaser-Hotz
h,f, J.A. Laissue i,f. aEuropean SynchrotronRadiation Facility,
B.P.220, F-38043 Grenoble Cedex, France; bINSERM unit836, CHU
Grenoble, Grenoble, France; cIm Neuenheimer Feld
280,69120Heidelberg,Germany; dCMRP, Northelds Ave., Wollongong,
2500, NSW,Australia; eUniversitat Bern Institut fr Anatomie
Baltzerstrasse 2CH-3000Bern 9, Switzerland; fCHU Grenoble,
Grenoble, France; gNiederwiesstr. 13c5417 Untersiggenthal,
Switzerland; hAnimal Oncology and Imaging Center,Rothusstr. 2,
CH-6331 Huenenberg/CH,.Switzerland; iUniversity of Bern,Faculty of
Medicine, Murtenstrasse 11, CH-3010 Bern, Switzerland
Background: Microbeam Radiation Therapy (MRT) uses a spatially
frac-tionated ltered white X-ray beam from a high energy wiggler
Synchro-tron Source (energies 50-350keV) with extremely high dose
rates (up toabout 20kGy/s). The typical planar beam width in an
array is 25-100mmwith 100-400mm wide spaces between beams. Such
beams are very welltolerated by the tissue, even the high peak
doses delivered in the path ofthe microbeams, when respecting a
dose prescription in the valley thatcorresponds to a dose used of
conventional Radiation Therapy (RT) con-verted to a single exposure
. The superior tumor control when compared tothat realized by
conventional RT is achieved by differential effects of MRTon the
normal tissue vasculature versus the tumor vasculature.Materials
and Methods: The MRT technique has been technically set up,tested
and successfully applied during the last 20 years on various
tumormodels. Presently, the project is mature enough to be used for
the treat-ment of spontaneous tumors in pets. Unied efforts from
several teamswith very different expertise now permit Microbeam
Radiation Therapy inanimal patients with a high degree of safety,
in pursuit of the ultimate goalof clinical applications in
humans.Results: The MRT trials for animal pets as tumor patients
required sub-stantial work for developing, upgrading and
progressively implementinginstrumentation, dosimetry protocol, as
well as the crucial patient safetysystems. Progress on the
homogenous dose measurements using ionisa-tion chambers and Alanine
dosimetry as well as the comparison of highresolution dosimeters
with the dose calculations based on a novel tumorplanning system
will be summarized. A general overview on the differentachievements
will be presented as well as a vision for possible humantrials.
TEXTURE AS IMAGING BIOMARKER
Costaridou Lena. Department of Medical Physics, School of
Medicine,University of Patras, Rion Patras 26504, Greece
Abstracts / PhysicQuantitative image analysis involves
derivation of quantitative measures(extraction of image features),
aiming to capture image manifestations ofconsidered. Representative
texture analysis approaches will be reviewedacross imaging
modalities, with reference to methodological and techno-logical
aspects and challenges. The advent of multimodality imaging
withnear isotropic 3-dimensional spatial resolution modalities,
includinganatomical and functional modalities, is expected to
enhance character-ization and quantication of naturally occurring
textures, as well as theirscale and orientation properties, while
casting insight to texture dynamics,provided by imaging tissue
volume times series (spatiotemporal data).
TECHNICAL CHALLENGES AND CLINICAL RESEARCH APPLICATIONS
OFULTRAHIGH FIELD MRI
AndrewWebb. Leiden University Medical Center, Radiology
Department, TheNetherlands
With the rapid spread of 7 Tesla whole body MRI systems
throughout theworld there has been signicant recent progress in
both clinical andclinical research applications. Although
predominantly in the neurologicalarea, there have also been many
developments in the areas of musculo-skeletal, cardiac and ocular
imaging. Increased magnetic susceptibilitycontrast, enhanced
magnetic resonance angiography, and much highersignal-to-noise in
spectroscopy and heteronuclear imaging/spectroscopyhave been the
driving forces for much of this progress. The major chal-lenges
have been, and continue to be, increased image inhomogeneity,power
deposition, and motion-induced artifacts. Many hardware
advanceshave already been necessary to deal with these problems,
and many futureadvances are required to keep the eld moving
forward.Examples which will be presented include: (i) the use of
navigator echoesand phase imaging for high resolution MRI in
Alzheimers patients, (ii) theuse of high dielectric materials to
improve neuroimaging and spectroscopyat high eld, (iii) diffusion
weighted metabolite spectroscopy in the brain,(iv) high eld cardiac
and musculoskeletal imaging, and (v) the design ofnew types of RF
coil specically for high eld.
DOSIMETRY IN SUPPORT OF PATIENT PROTECTION IN
DIAGNOSTICRADIOLOGY - A VALEDICTORY VIEW FROM THE UK
Dr Paul C. Shrimpton. Formerly Leader of Medical Dosimetry
Group, PublicHealth England, Chilton, OX11 0RQ, UK
Invited lecture in relation to EFOMP Medal Award CeremonyThe
increasingly widespread use of x-rays in diagnostic radiology
providesnot only enormous benets to patients, but also signicant
radiationexposure for populations. The protection of patients
against potential ra-diation harm requires the elimination of all
unnecessary x-ray exposure inrelation to effective clinical
diagnosis. Dosimetry is an essential manage-ment tool for patient
safety by allowing the assessment of typical radiationrisks in
support of the justication of procedures, and the routine
moni-toring and comparison of typical doses in pursuit of the
optimisation ofpatient protection. Periodic assessment of patient
doses should form anintegral part of quality assurance in x-ray
departments and is best based onpractical measurements that provide
useful characterisation of patientexposure, such as entrance
surface dose, dose-area product and, for CT,volume-weighted CT dose
index and dose-length product. Mean valuesunderlying
pathophysiological processes, with the ultimate goal to
identifyimage-based biomarkers and improve patient-specic disease
manage-ment. While features capturing lesion contrast and shape,
also mimickingradiologists used image attributes, have been
extensively studied in theframework of image-based computer aided
diagnosis texture analysis, notdirectly intuitive to radiologists,
is an emerging approach. In addition, thetissue appearance modeling
and classication task has been recentlyenriched, encompassing
tasks, such as prognosis, monitoring diseaseprogression and
response to therapy, as well as cancer risk assessment.Prognosis
imaging biomarkers assess neoplasm aggressiveness, in terms oftheir
relationship to pathology and molecular classication, while
treat-ment response imaging biomarkers could help early
identication of re-sponders/non responders to neo-adjuvant
chemotherapy schemes prior tosurgical decisions. In this review,
texture analysis methodologies exploitedtowards the identication of
potential imaging biomarkers will be
dica 30S1 (2014) 5determined in a department for these practical
dose monitoring quanti-ties, from patient samples for each type of
examination and patient group,
-
Badly written papers, not complying with requirements and
including
Abstracts / Physica Medica 30S1 (2014)6can form the basis not
only for estimates of typical organ and effectivedoses to reference
patients utilising appropriate coefcients, but also localdiagnostic
reference levels (DRLs). DRLs represent a pragmatic mechanismfor
promoting continuing improvement in performance by
facilitatingcomparisonwith national values and practice elsewhere.
The developmentand application of DRLs in the UK over the last 30
years, within a coherentframework for patient protection that has
included periodic nationalsurveys for conventional x-rays and CT,
has successfully helped reduceunnecessary exposures, with national
DRLs for many examinations havingfallen by a factor 2.
HOW TO OPTIMIZE EXPOSURES USING RADIOBIOLOGY AS A GUIDE
Klaus Trott, Vere Smyth, Andrea Ottolenghi. Department of
Physics,University of Pavia, Via Bassi 6, 27100, Pavia, Italy
Medical radiation exposures associated with the diagnosis and
treatmentof diseases are, besides natural background irradiation,
the main source ofradiation burden to mankind and may lead to an
increased risk of variousdiseases such as cancer, cardiovascular
diseases, developmental disordersand heritable health injury.
Concepts for radiation risk estimation andreduction were developed
by ICRP, yet they do not apply to individualpatients but to the
population at large. They are designed to be used asguidelines for
planning safe procedures e.g. in industry and publichealth.
Population risk estimates are based on mean doses to a list
ofcritical organs and on tissue weighting factors. The estimation
of radia-tion risks for individual patients, however, has to be
based on the deter-mination of anatomical dose distribution within
the exposed organs emean doses may be meaningless. Even within the
same organ, pathology,pathophysiology and pathogenesis differ
between different potentialhealth complications from medical
radiation exposures of the differentorgans. They depend on dose to
critical structures and subvolumes, on ageand sex of the exposed
patient and most likely also on genetic predispo-sition and life
style factors. Both, for diagnostic exposures and
therapeuticexposures of the individual patient, estimations of
health risks need to bebased on radiobiological mechanisms of
pathogenic pathways. Models ofrisk estimation in particular those
from therapeutic exposures are notspecic for particular organs but
for particular clinical manifestation ofradiation-induced disorders
and diseases. Moreover, dose volume histo-grams are of little value
in these estimates since anatomy is more impor-tant than volume.
Several exposure scenarios in diagnostic and therapeuticradiology
will be discussed to explain the problems and suggest
possibil-ities to solve the problems.Acknowledgments. This work was
partially funded by EU (EC Contract FP7605298, EUTEMPE-RX).
HOW TO PUBLISH A PAPER IN A PEER-REVIEWED JOURNAL
David Thwaites. Institute of Medical Physics, School of Physics,
University ofSydney, NSW2006, Australia
Publication of work is necessary to move the eld forward. Using
experi-ence as an author, reviewer, editorial board member and
editor, someobservations are summarized onwriting a paper,
submitting it and gettingit published, focussing on what makes a
good paper and hence likely to beacceptable.First, consider
yourmainmessage and hencematerial selection andwritingow so that
this is clear. Make the introduction relevant towhere the workts
into current related research, going quickly from generalities to
spe-cics. Even good well-presented work will not get into
high-impact-factorjournals unless it is clearly novel and/or
signicant. Methods should allowthework to be repeated; ask yourself
if they are clear and complete. Explainacronyms. Results should
clearly tie gures and tables to text. Conclusionsshould relate back
to the key message and be veriably supported by re-sults.
Discussion and conclusions should not just be re-stated results!Ask
a colleague, unconnected with the work, to read the nal draft
paperand give comments on clarity. If they can't understand it,
neither will thereferees! Re-read it yourself after a time gap.
Check journal requirementsand comply! Hastily prepared submissions
are usually poorly prepared!mistakes, eg in references, immediately
give the impression that the workmay also be poor. Work with
experienced authors initially (eg supervisor).Look critically at
papers you read and notewhat you thinkworkswell. Newwriters can
learn good practice by example. Good luck!
REASONS FOR REJECTION
Paolo Russo. Universita di Napoli Federico II, Naples, Italy
Rejection of a paper refers to the decision of the Editor of a
scienticJournal not to accept the submitted manuscript for
publication in thatJournal. This condition may occur in any phase
of the paper evaluationprocess, but mostly occurs at the end of the
rst round of the peer-reviewprocess, i.e. when one of two experts,
asked for their independentopinion, suggest reasons for acceptance,
revision or rejection of themanuscript. Typically, in the case of a
negative peer-review, the AssociateEditor expresses a
recommendation (e.g., reject) for the Editor-in-Chief,who takes the
nal decision. The rejection rate of a Journal, i.e. the ratio ofthe
number of rejected to the number of evaluated manuscripts, has
beenseen to increase over the last years in many well-reputed
scienticJournals, also in the case of medical physics Journals, and
this has causedconcern both in the Journal's Editorial Boards, and
in the authors' com-munity. For example, for the Journal Physica
Medica (European Journal ofMedical Physics, EJMP) the rejection
rate is such that only about onemanuscript out of three is accepted
for publication. This has thenprompted various actions from
scientic Publishers and Journal Editors,in order to increase the
awareness of the authors toward the scienticwriting best practice,
the peer-review process and the Journals' wholepaper evaluation
process. This presentation, by the Editor-in-Chief ofEJMP,
indicates possible reasons for paper rejection, based on the
pre-senter's experience as an author, as a reviewer, as Associate
Editor and asEditor of a scientic Journal in medical physics. These
reasons mayinclude lack of proper English writing, lack of
motivations or originality,weaknesses in the methodological aspects
or in the signicance of thendings and other specic reasons, which
overall may indicate a generallack of convincing strength of the
manuscript. Since publishing in a well-reputed scientic Journal is
a competition for the acquisition of theconsensus in the Journal's
audience, and hence in the correspondingscientic community, toward
the work carried out in the specic study,lack of strength of a
manuscript for one or more of the above reasons invariably leads to
paper rejection. Ultimately, the efforts by the scienticcommunity
toward reaching the best practice in scientic writing
andevaluation, will hopefully produce a reduced Journals' rejection
rate, andmost importantly, an improved efcacy of the research work,
for thebenet of the scientic and social progess.
THE CURRENT STATUS OF MEDICAL PHYSICS RECOGNITION IN EUROPE
Stelios Christodes. Medical Physics Department, Nicosia General
Hospital,Nicosia, Cyprus
The European Union recognises professions automatically if they
meet therequirements of Directive 2005/36/EC [1], as this was
amended by Direc-tive 2013/55/EU [2]. Automatic profession
recognition gives the right ofprofessionals to move and work
without any restrictions in any MemberState of the European
Union.European recognition of the Medical Physics profession will
allow Clini-cally Qualied Medical Physicists (CQMP) the same
privileges as otherrecognised professions, such as Medical Doctors,
Architects, Nurses, etc.Furthermore, Medical Physics Experts (MPE),
as dened by Directive 2013/59/Euratom [3, 4], can have the same
privileges, if are recognised by all theCompetent Authorities of
all the Member States of the European Union.Currently, neither the
CQMPs nor the MPs are recognised automatically asa profession by
all the Member States of the European Union. The Euro-pean
Federation of Organisations for Medical Physics (EFOMP) is
workingfor many years in developing the education, training and
competence ofMedical Physicists, both at the CQMP and MPE levels so
as the
-
a Merequirements of the above Directives are met for automatic
professionalrecognition.The purpose of this presentation is to give
a brief account of the effortsmade by EFOMP and the requirements
that need to be met, at the nationallevel, in order for both the
CQMPs and MPEs can be automatically recog-nised by the European
Union.References[1] Directive 2005/36/EC of the European Parliament
and of the Council of7 September 2005 on the recognition of
professional qualications, OJL255, 30.9.2005, pp 22-142.[2]
Directive 2013/55/EU of the European Parliament and of the Council
of20 November 2013 amending Directive 2005/36/EC on the recognition
ofprofessional qualications and Regulation (EU) No 1024/2012 on
admin-istrative cooperation through the InternalMarket Information
System (theIMI Regulation), OJ L354, 28.12.2013, pp 132-170.[3]
Council Directive 2013/59/Euratom of 5 December 2013 laying
downbasic safety standards for protection against the dangers
arising fromexposure to ionising radiation, and repealing
Directives 89/618/Euratom,90/641/Euratom, 96/29/Euratom,
97/43/Euratom and 2003/122/Euratom,OJ L13, 17.1.2014, pp. 1-73.[4]
European Commission, Radiation Protection Report 174, Guidelines
onMedical Physics Expert, Directorate-General Energy, Luxembourg,
2014,available from:
http://ec.europa.eu/energy/nuclear/radiation_protection/doc/publication/174.pdf
(last accessed on the 11th of May 2014).
THE CURRENT STATUS OF MEDICAL PHYSICS RECOGNITION IN THEMIDDLE
EAST
Ibrahim Duhaini. Chief Medical Physicist & RSO, Rak Hariri
UniversityHospital, Beirut - Lebanon & President of the Middle
East Federation ofOrganizations of Medical Physicists (MEFOMP),
Lebanon
Medical physics is the branch of physics concerned with the
application ofphysics to medicine, particularly in the diagnosis
and treatment of humandiseases. From the time whenWilhelm Roentgen
and other physicists madethe discoveries which led to the
development of Diagnostic Radiology,Radiotherapy, Brachytherapy and
Nuclear Medicine, Medical Physicistshave played a pivotal role in
the development of new technologies thathave revolutionized the way
medicine is practiced. In today's health carescene, the medical
physicist is essential to the safe and cost effectiveoperation of
any creditable medical institution.Medical Physics in the Middle
East Region has passed in different stages. Inparticular the ISEP
Conference held in Bahrain in November 2007 and the16 th ICMP
Conference held in Dubai in 2008. During these conferences,there
were several meetings for all the medical physics societies in
theMiddle East. The result was the establishment in September 2009
of theMiddle East Federation of Organizations in Medical Physics
(MEFOMP)which is part of the International Organization of Medical
Physics IOMP.The following countries have signed up for this
chapter: Bahrain, Iran, Iraq,Jordan, KSA, Lebanon, Oman, Qatar,
Syria, UAE and Yemen. Ever since then,the medical physics
profession has gone the rst mile in the road ofrecognition in most
of the ME countries. Governmental entities and Uni-versity bodies
started looking deeply into the need of promoting MP ac-tivities
across the region.Now, Medical physicists in the ME region are
considered scientists whothrough science are able to identify
problems and unveil deciencies. It isalso through science that they
solve the problems and correct the de-ciencies encountered in the
diagnosis and treatment of diseases.There will be exciting and
difcult challenges not only in the eld of healthcare but also in
the race for nuclear power in the ME region. Countries willbe
counting on the science of Medical Physics to help meet
thesechallenges.Keywords: IOMP, MEFOMP, Middle East, Medical
Physics, Recognition.
EDUCATION AND TRAINING OF MEDICAL PHYSICISTS IN EUROPE
V. Tsapaki. Konstantopoulio General Hospital, Athens, Greece
Background:Medical exposure represents the utmost and fastest
growing
Abstracts / Physiccontribution to manmade radiation exposure not
only in Europe but alsoacross the world. Furthermore, the evolution
of medical equipment istherefore become part of an indispensable
core team within the hospitalto ensure safe and procient use of
medical equipment. His presence isgrowing alsowithin the industry
and/or regulatory authority environment.In order to meet all these
demands, sufcient education and training isindispensable.
Collaboration and innovation in this eld is imperative forthe
appropriate professional response to all these challenges. The
Euro-pean Commission has for a number of years recognized the need
foradequate theoretical and practical training of medical
physicists for thepurpose of radiological practices. This is
clearly stated in a number ofEuropean directives as well as in the
latest European Basic Safety Stan-dards. A number of questions
arise based on all these facts. Do we havesufcient number of
adequately trained medical physicists or medicalphysics experts to
address the needs of the increasing number of medicalprocedures in
Europe? Is the education and training of such scientistsharmonized
across Europe, that will facilitate in easier and mutualrecognition
as well as improved cross-border mobility of medical physi-cists?
The present paper will attempt to answer these questions using
themost recent information within Europe.
EDUCATION AND TRAINING OF MEDICAL PHYSICISTS IN MIDDLE
EASTKINGDOM OF BAHRAIN AS AN EXAMPLE
Lama Sakhnini. Department of Physics, College of Science,
University ofBahrain, Sakhir, PO. Box 32038, Kingdom of Bahrain
Education: TheDepartment of Physics at University of Bahrain
offers a B.Sc.in medical physics program. The program produces
B.Sc. degree graduateswith a broad knowledge of fundamental and
applied physics. With aspecialization in medical physics, the
graduates will be eligible foremployment in hospitals, clinics,
environmental establishments or indus-trial health care centers.
Students should also be suitably prepared to carryout research in
medical physics leading to a higher degree. The B.Sc. inMedical
Physics degrees gives the opportunity to study the many
medicalapplications of advanced physics.Medical physics courses,
taught by staff ofthe department of Physics, are supplemented by
specialist lectures given bysenior practicing medical physicists
and doctors from Salmaniya medicalcomplex and Bahrain Defense force
hospital. The B.Sc. programs inMedicalPhysics shares many common
courses with the B.Sc. program in Physics,but nearly 48 credit
hours include courses which are specic to MedicalPhysics program. A
total of 42 female students graduated from the programso far, only
3 students managed to get jobs in the medical sector.Training: The
B.Sc. in Medical Physics program ensures that the studentsgo
through clinical training at hospitals in the Kingdom of Bahrain or
in theKingdom of Saudi Arabia. In an ideal situation; the student
spends aminimum of 2months of hospital training to complete a
clinical rotation inradiation therapy, diagnostic imaging and
nuclear medicine. The studentobserves and practices clinical
procedures under the direct supervision ofa senior clinical medical
physicist. The student is required to write aprogress report on the
clinical procedures. However there is no welldesigned training
program in the hospitals. Hence there is a disparate needfor a
Residency Program which is aimed at both educating and
providingpractical experience so that the medical physicist would
be ready topractice in a hospital setting and obtain board
certication. Training for ourstudents faced many challenges, as
most hospitals do not have medicalphysicists, most hospital
administrators do not know the rule of medicalphysicists, many
hospitals have no quality management program and relyon the medical
supplier of their equipment to do yearly maintenance.
EDUCATIONAL ACCREDITATION IN MEDICAL PHYSICS: IS
ITIMPORTANT?
John Damilakis. Professor of Medical Physics, Greece
An increasing number of higher education institutions have in
recent yearsstarted to offer courses on Medical Physics. Moreover,
Continuing Profes-sional Development (CPD) for medical physicists
is of great professionalcontinuous and fast, increasing the demand
for high level scientists andexperts in the eld. To ensure that
ionizing radiation is safely used, thepresence of the medical
physicist is essential. The medical physicist has
dica 30S1 (2014) 7interest. CPD courses is an excellent way to
ensure that Medical Physicists
-
Abstracts / Physica Medica 30S1 (2014)8become knowledgeable
about all current issues in their eld and to pro-vide the necessary
knowledge, skills and competences for certied Med-ical Physicists
to become Medical Physics Experts. However, externalassessment of
the quality of education or training provision is
needed.Accreditation is the formal recognition that education and
training onmedical physics provided by an institution meets
acceptable levels ofquality. Accreditation should be based upon
standards and guidelines.Requirements for accreditation of a
training programme should take intoaccount several aspects
including facilities, staff, educational material andteaching
methods. In Europe, ENQA (European Network for QualityAssurance)
promotes European co-operation in the eld of QualityAssurance in
higher education. ENQA members are national agencies
andorganizations, which play a major role in the accreditation
process. A Eu-ropean organization is needed to offer accreditation
of medical physicsCPD and training programs. Certication is the
recognition of knowledge ofa professional who has completed his/her
education or training. The EC hasdeveloped tools and frameworks to
promote training and facilitatemobility. ECVET is a European system
of accumulation and transfer ofcredits designed for vocational
education and training in Europe.
IMAGE-GUIDED RADIATION THERAPY IN THE PRECLINICAL SETTING
Ross Berbeco PhD. Department of Radiation Oncology, Brigham
andWomens Hospital, Dana-Farber Cancer Institute and Harvard
MedicalSchool, USA
Current clinical radiation therapy is delivered with multiple
collimatedbeams and accurate radiation dose calculation based on CT
imaging.Additional advances in image-guided delivery techniques
have saturated amajority of modern clinics. Therefore, modern
translational research ofradiation biology and radiation physics
using in vivo models of cancer re-quires a preclinical therapy
platform that has the same capabilities asmodern clinical linear
accelerators. In 2010, we established a preclinicalradiation
biophysics laboratory at the Dana-Farber Cancer Institute
andHarvardMedical School (Boston,MAUSA). The cornerstone of this
facility isa Small Animal Radiation Research Platform (SARRP) which
was developedby researchers at Johns Hopkins University (Baltimore,
MD USA) andcommercialized by Xtrahl, Inc. (Surrey, UK). The SARRP
combines a con-ventional x-ray tube with brass collimators to
enable delivery of photonbeams as narrow as 0.5 mm at 220 kVp.
Precise (sub-mm) image-guidedsetup is performed using cone-beam CT
imaging combined with a roboticmotion stage. Absolute dose output
is measured with an ADCL-traceableion chamber. Percentage
depth-dose and beam proles are measured foreach collimator with
EBT3 lm. Monte Carlo modeling of the SARRP isperformed using
EGSnrc. The phase space les are used in a GPU-driven 3Ddose
calculation engine with the 3D Slicer platform for
visualization(Brigham andWomens Hospital Surgical Planning
Laboratory, Boston, MAUSA). Collimator size, gantry and collimator
angles, and target prescriptionare given and a 3D isodose
distribution is calculated. Measurements inheterogeneousmedia have
validated the dose calculation accuracy. Routinequality assurance
procedures have been developed, based on thoseemployed for clinical
radiation devices. The laboratory has facilities foranimal surgery,
housing, anesthesia and injection. Our SARRP has beenoutttedwith a
tube for continuous isourane delivery during imaging andtherapy
procedures. To date,more than 1,000 preclinical procedures on
liveanimals have been performed in the laboratory. Examples of
currenttranslational research applications include genetic
dependence of radiationresistance, chemical radiation sensitizers,
metabolic modiers of radiationtherapy efcacy, metallic
nanoparticles for enhanced radiation therapy andimaging contrast,
and dermatologic studies. We anticipate that by utilizinga research
instrument that provides accurate and precise radiation
delivery,the results will have high translational relevance.
Funding for these pro-jects has come from the United States
Department of Defense, the NationalInstitutes of Health,
philanthropic foundations and internal sources.
THE GEANT4-DNA PROJECT: OVERVIEW AND STATUS
Sebastien Incerti. CNRS, Bordeaux University, FranceOn behalf of
the Geant4-DNA collaborationUnderstanding and prediction of adverse
effects of ionizing radiation atthe cellular and sub-cellular scale
remains a challenge of todays radiobi-ology research. In this
context, a large experimental and modeling activityis currently
taking place, aimed at better understanding the biologicaleffects
of ionizing radiation at the sub-cellular scale. The
Geant4-DNAproject was initiated by the European Space Agency [1].
It aims to developan experimentally validated simulation platform
for the modeling of earlyDNA damage induced by ionizing radiation,
using modern computing toolsand techniques. The platform is based
on the general-purpose and open-source Geant4 Monte Carlo
simulation toolkit, and benets from thetoolkits full transparency
and free availability [2].This project proposes to develop specic
functionalities in Geant4allowing:1) The modeling of elementary
physical interactions between ionizingparticles and biological
media, during the so-called physical stage.2) The modeling of the
physico-chemical and chemical stages corre-sponding to the
production, the diffusion and the chemical reactionsoccurring
between chemical species. During the physico-chemical stage,the
water molecules that have been excited and ionized during the
physicsstage may de-excite and dissociate into initial water
radiolysis products. Inthe chemical stage, these chemical species
diffuse in the medium sur-rounding the DNA. They may eventually
react among themselves or withthe DNA molecule.3) The introduction
of detailed biological target geometry models, wherethe two above
stages are combined with a geometrical description ofbiological
targets (such as chromatin segments, cell nuclei). The Geant4-DNA
physics processes and models are fully integrated into the
Geant4toolkit and can be combined with Geant4 geometry modeling
capabilities.In particular, it becomes possible to implement the
geometry of biologicaltargets with a high resolution at the
sub-micrometer scale and fully trackparticles within these
geometries using the Geant4-DNA physics pro-cesses. These
geometries represent a signicant improvement of thegeometrical
models used so far for dosimetry studies with the Geant4toolkit at
the biological cell scale.The current status of the project will be
presented, as well as on-goingdevelopments.[1] S. Incerti et al.,
Comparison of Geant4 very low energy cross sectionmodels with
experimental data inwater , Med. Phys. 37, 4692-4708 (2010)[2] S.
Agostinelli et al., Geant4-a simulation toolkit, Nucl.
Instrum.Methods. Phys. Res. A. 506, 250-303 (2003)
FIELD-CYCLING MRI: A NEW IMAGING MODALITY?
David J. Lurie, Lionel M. Broche, Gareth R. Davies, Nicholas
Payne,Kerrin J. Pine, P. James Ross, Vasileios Zampetoulas.
Aberdeen BiomedicalImaging Centre, University of Aberdeen, AB25
2ZD, Scotland, UK
Much of the contrast in conventional MRI arises from differences
in theNMR relaxation times, especially the spin-lattice relaxation
time, T-1. It isalso well known, from in vitromeasurements on small
tissue samples, thatthe variation of T1 with the strength of the
applied magnetic eld B0(known as T-1-dispersion) is
tissue-dependent, and that the shape of atissues T-1-dispersion
curve is altered in disease. However, T-1-dispersionis invisible to
conventional MRI scanners, because each scanner can onlyoperate at
its own native magnetic eld (e.g. 1.5 T, 3.0 T). The aim of ourwork
is to exploit T-1-dispersion as a new MRI contrast mechanism,
bybuilding new types of MRI scanner which make use of Fast
Field-Cycling(FFC) [1].In FFC, the applied magnetic eld is switched
rapidly, while the sample (orpatient) is inside the scanner. Thus,
the nuclear magnetisation can bemadeto evolve at a range of
magnetic eld strengths, allowing the measurementof T-1-dispersion.
The magnetic eld is always switched to the same valueprior to
measurement of the NMR signals, so that the instruments
radi-ofrequency system does not require retuning during the
procedure.In our laboratory we have built two whole-body human
sized FFC-MRIscanners, one of whichmakes use of a dual magnet in
order to achieve eldswitching [1,2]. The detection eld of 59 mT is
provided by a vertical-eld,permanent magnet. Inside its bore is
located a resistive magnet whichgenerates an opposing magnetic eld;
eld-cycling is achieved by
switching the current in the resistive magnet coil.
-
A o ti he -to (C h it semission scan d ) o ta )
a MeWe have begun to explore bio-medical applications of
FFC-MRI, and earlyresults have shown promise in the areas of
thrombosis [3] and in osteo-arthritis [4], where the technique
seems to be an indicator of early disease-related changes. FFC-MRI
is showing signicant potential as a new variantof MRI. Please
consult our web site (www.ffc-mri.org) for furtherinformation.[1]
Lurie D.J., Aime S., et al., Comptes Rendus Physique 11, 136-148
(2010).[2] Lurie D.J., Foster M.A., et al., Phys.Med.Biol. 43,
1877-1886 (1998).[3] Broche L.M., Ismail S. et al.,
Magn.Reson.Med., 67, 1453e1457 (2012).[4] Broche L.M., Ashcroft G.P
and Lurie D.J., Magn.Reson.Med. 68, 358-362(2012).
STANDARDS FOR MRT DOSIMETRY: THE METROMRT PROJECT
Vere Smyth a, Christophe Bobin b, Lena Johansson a,
LeilaJoulaeizadeh c, Marco DArienzo d,e, Marco Capogni d, HansRabus
f, Maurice Cox a, Jaroslav Solc g. aNational Physical Laboratory
NPL,Hampton Road, Teddington, Middlesex, TW11 0LW, UK;
bCommissariat alEnergie Atomique (CEA) Bt 476, Pt Courrier 142,
CEA-Saclay, FR-91191 Gif-sur-Yvette Cedex, France; cVSL, Dutch
Metrology Institute, Thijsseweg 11,P.O. Box 654, NL-2629, JA Delft,
Netherlands; dNational Institute of IonizingRadiation Metrology,
ENEA-INMRI, C.R. Casaccia, 00123 Rome, Italy;eDepartment of Human
Anatomy, Histology, Forensic Medicine andOrthopedics, Sapienza
University of Rome, Via Borelli 50, 00161 Rome,Italy;
fPhysikalisch-Technische Bundesanstalt (PTB), Bundesallee 100,
D-38116 Braunschweig, Germany; gCzech Metrology Institute
(CMI),Inspectorate for Ionising Radiation, Radiova 1, CZ-102 00
Prague 10,Czech Republic
The outcome for the patient of a molecular radiotherapy (MRT)
procedureis determined by the radiation doses to the target tissue,
and to criticalnormal tissue. It is well known that there is a wide
variation betweenindividual patients in these doses for the same
administered radiophar-maceutical activity. Generally a patient is
given the maximum activity thatwill be tolerated by the normal
tissue, on the basis of average populationstatistics obtained
during clinical trials, in the hope that an effectivetreatment dose
will be received. This practice could clearly be optimised ifthe
respective doses could be determined for each patient, and the
pre-scription based on this knowledge. Many clinical research
centres aredeveloping dosimetry methods of increasing
sophistication and accuracy,but to date these developments have
very rarely had any effect on indi-vidual patient management. There
are many reasons why this is so, but theobvious difference between
MRT and other radiotherapy modalities is theabsence of a standard,
internationally endorsed dosimetry protocol.Development of a
dosimetry protocol analogous to the IAEA TRS398 pro-tocol (Absorbed
dose determination in external beam radiotherapy, IAEA,Vienna,
2000) is difcult because of the complex nature of the steps in
theMRT dosimetry process and dependence on the radiopharmaceutical
be-ing used. However, difcult does not imply impossible. An
internationalproject funded under the European Metrology Research
Programme,MetroMRT (http://projects.npl.co.uk/metromrt/), is
currently makingprogress in addressing this problem. The dosimetry
process is analysedinto its component parts: activity measurement,
quantitative imaging (QI),activity-time integration, and dose
calculation, fromwhich ameasurementchain is constructed, traceable
to primary radiation standards of radioac-tivity and absorbed dose,
with an evaluated uncertainty. The greatestdifculties are relating
a standard QI calibration to a measurement on apatient, and
accounting for the uncertainty resulting from the combinationof
different biokinetics, measurement time points, and
integrationmethods in determining the uncertainty in the
activity-time integrationstep. The MetroMRT project is in the nal
year of its 3-year duration. De-tails of the individual tasks and
success achieved so far will be presented.
RADIOPHARMACEUTICAL DOSIMETRY: FROM THE ANIMALS TO
THECLINICS
Manuel Bardies. UMR 1037 INSERM/UPS, Centre de Recherche
enCancerologie de Toulouse, Toulouse, France
Abstracts / PhysicNuclear Medicine dosimetry is not limited to
the clinical scale (i.e. organ ortumor).that in clinical practice
can be selected by the user, or object properties(such as target
dimensions, target-to-background (T/B) ratio and activityoutside
the eld of view) which depends uniquely on the intrinsic
char-acteristics of the object being imaged.Methods and Results: In
the rst experiment CNR was studied as afunction of ESD and Aacq for
different target sizes and T/B ratios using amultivariate approach
in a wide range of conditions approaching the onesthat can be
encountered in clinical practice. Sequential imaging was per-formed
to acquire PET images with varying background activity
concen-trations of about 12, 9, 6.4, 5.3 and 3.1 kBq/mL. The ESD
was set to 1, 2, 3,and 4 min/bed. The ESD resulted as the most
signicant predictor of CNRvariance, followed by T/B ratio and the
cross sectional area of the givensphere. Only last comes Aacq with
a weight halved with respect to ESD.Thus, raising ESD seems to be
much more effective than raising Aacq inorder to obtain higher
CNR.In the second experiment a scatter phantom was positioned at
the end ofthe modied IEC phantom to simulate an activity that
extends beyond thescanner. The modied IEC phantomwas lled with 18F
(11 kBq/mL) and thespherical targets had a target-to-background
ratio of 10. PET images wereacquired with background activity
concentrations into the FOV (Ac,bkg)about 11, 9.2, 6.6, 5.2 and 3.5
kBq/mL. ESD was set to 1, 2, 3, and 4 min. Thetube inside the
scatter phantom was lled with activities to provide anAc,out in the
whole scatter phantom of zero, half, unity, twofold and four-fold
the one of the modied IEC phantom. CNR diminishes signicantlywith
increasing outside FOV activity, in the range explored. ESD and
Ac,outhave a similar weight in accounting for CNR variance. A
recovery of CNR
loin
ss due to an eindividual beuration (ESDlevated Ac,out actd
positions accor activity at the sivity seems feasiblerding to the
Ac,out.rt of acquisition (Aacq)
-noise ratio NR)) behavew en varying acquis ion parameters (such
a
im: The aim f this presenta on is to describe t way inwhich
contrastPreclinical studies, involving animal (or cell experiments)
also can benetfrom sound dosimetric studies. Small animal studies
are required duringthe development of new radiopharmaceuticals
(diagnostics or therapy).The general relevance of
radiopharmaceutical dosimetry applies equally topreclinical and
clinical studies. The MIRD scheme can most often beapplied, even at
the cellular level, as long as macrodosimetric parameters(mean
absorbed doses) remain relevant.However, there are differences in
the goals and in the methodologyrequired to perform studies:For
diagnostic tracers, during the development phase,
small-animalradiopharmaceutical biodistribution and
pharmacokinetics are frequentlyextrapolated to humans. However,
absorbed dose delivered are usually notconsidered.For therapeutic
nuclear medicine, absorbed doses are computed to docu-ment the
biological effect observed (efcacy/therapy), and that can
beperformed in a preclinical context. As for clinical dosimetry,
the issue ofmodel versus specic dosimetry must be addressed.
Cumulated activity is most often determined from organ/tissues
activitymeasurements at different time points, from ex vivo
counting. Absorbed dose calculation can be carried out with more or
less sophis-ticated radiation transport codes.The table below
presents the variouspossibilities offered to perform nuclear
medicine dosimetry at the clinicalscale. How that table can be
extrapolated in a context of preclinicaldosimetry will be
discussed.
Context Cumulatedactivity (Bq.s)
S values(Gy.Bq-1.s-1)
Absorbeddose (Gy)
Diagnostics Model Model Model-basedTherapy Specic Model adjusted
Model-based realisticTherapy Specic Specic Specic
Within multidisciplinary teams involved in radiopharmaceutical
research, physi-cists should not only focus on the clinical aspects
but also participate to preclinicalstudies.
ACQUISITION PROTOCOLS FOR 18F-FDG WHOLE BODY PET/CT:OPTIMIZING
SCAN DURATION VERSUS ADMINISTERED DOSE
Marco Brambilla. Medical Physics Department, University Hospital
OfNovara, Novara, Italy
dica 30S1 (2014) 9bymodulating the ESD
-
MeConclusions: The European Association of Nuclear Medicine
procedureguidelines for whole-body FDG-PET scanning still prescribe
a dose pro-portional to the patients body mass. However, clinical
practice andexperimental evidences show that using an FDG dose
proportional to bodymass does not overcome size-related degradation
of the image quality anddifferent algorithms should be devised
instead.
NEW ANALYTICAL ALGORITHMS FOR PET AND SPECT
George Kastis. Academy of Athens, Medical & Biological
Research Foundation(IIBEAA), Athens, Greece
Positron emission tomography (PET) and single-photon
emissioncomputed tomography (SPECT) are the most important nuclear
medicineimaging modalities that measure the in vivo distribution of
imagingagents labeled with emitting radionuclides. Image
reconstruction is anessential component of both modalities,
allowing tomographic images tobe obtained from a set of
two-dimensional of three-dimensional projec-tion data. The existing
image reconstruction methods can be classiedinto two main
categories: analytical methods and iterative (or
statistical)methods.Filtered backprojection (FBP) is the
predominant analytic reconstructionmethod. Its mathematical
formulation is based on the inversion of theRadon transform through
the central slice theorem. The main advantagesof FBP are speed and
simplicity. However, in FBP it is difcult to incorporatecomplex
physical phenomena such as attenuation and scatter. The
pre-dominant iterative algorithms are the maximum-likelihood
expectation-maximization (MLEM) algorithm and its accelerated
successor the or-dered-subsets expectation-maximization (OSEM)
algorithm. The mainadvantage of the iterative algorithms is the
ability to model several aspectsof the imaging system, including
elements of the noise characteristics,sinogram blurring due to
detector crystal penetration, depth of interaction,photon scatter,
and attenuation in the body. As a consequence, iterativemethods can
improve image quality and achieve considerable resolutionrecovery.
However, iterative algorithms require more computing time andpower.
Furthermore, there is the challenge of choosing the right number
ofsubsets and iterations which leads to a tradeoff between noise
and bias.Although iterative methods are now in widespread use in
clinical andpreclinical systems, recent studies have concluded that
analytical methodscould still have advantages over analytic methods
in specic applications.For example, a recent dynamic brain PET
study by Reilhac et al. concludedthat analytical methods are more
robust to low count data than iterativemethods. In another study by
Conti et al., it was demonstrated that TOF FBPhas improved
performance over TOF OSEM.In this presentation we will present
recent results from the spline recon-struction technique (SRT), a
new analytic, two-dimensional reconstructionalgorithm based on
cubic splines. We will present the mathematicalformulation of the
algorithm and comparisons with FBP and OSEM, usingsimulated data
from a clinical PET system, as well as real data obtainedfrom
clinical and preclinical PET scanners. Furthermore, we will
presentpreliminary results from IART (inverse attenuated Radon
transform), ananalytic reconstruction technique based on cubic
splines that inverts theattenuated Radon transform and is better
suited for SPECT where atten-uation correction is needed.
AN OVERVIEW OF THE CONCERT PROJECT
John Damilakis. Professor of Medical Physics, University of
Crete, Greece
The overall aim of the CONCERT (Conceptus Radiation Doses and
Risksfrom Imaging with Ionizing Radiation) project is to perform
originalresearch fromwhich new ndings, innovations and practical
guidelines foroptimal clinical management of pregnant patients
needing radiologicprocedures will result. An additional objective
is to generate dose data thatmay be used for the implementation of
a radiation protection programdesigned for pregnant employees
working in imaging departments,interventional laboratories and
electrophysiological suites.The activities of the project focus on
the following main tasks:a) Conduction of a nation-wide study
(survey) on current practice patterns
Abstracts / Physica10in imaging of pregnant patients and on
policies for screening women ofchildbearing age for pregnancy
before imaging with ionizing radiationb) Development of methods for
estimation of conceptus dose from imag-ing examinations performed
on the motherc) Development of a method for (a) anticipation of
conceptus dosefrom occupational exposure of pregnant staff during
uoroscopically-guided procedures and (b) estimation of maximum
workloadallowed for each month of gestation period following
pregnancydeclarationd) Development of a software expert system that
will allow a) calculationof conceptus radiation dose and risk
associatedwith imaging examinationsperformed on the expectant
mother and (b) anticipation of conceptusdose and determination of
the maximum workload for the pregnantemployee who participates in
uoroscopically-guided interventionalprocedurese) Organization of a
workshop on pregnancy and radiation protection todiscuss the ndings
of the survey and disseminate the research results.f) Development
of guidance document on a) the management of pregnantpatients who
need radiologic examinations, b) the management of preg-nant
employees exposed to considerable levels of occupational
radiationand c) policies for screening women of childbearing age
for pregnancybefore imaging proceduresThe project started in
September 2012 and ends in September 2015.CONCERT is supported by
the Greek Ministry of Education and ReligiousAffairs, General
Secretariat for Research and Technology, OperationalProgram
'Education and Lifelong Learning', ARISTIA.
HOW TO ESTIMATE CONCEPTUS RADIATION DOSE FROMRADIOGRAPHIC,
FLUOROSCOPIC AND FLUOROSCOPICALLY GUIDEDINTERVENTIONAL PROCEDURES?
(REVIEW COURSE TALK FOR THECONCERT PROJECT)
G. Solomou, J. Stratakis, J. Damilakis. Department of Medical
Physics,Faculty of Medicine, PO Box 2208, University of Crete,
Iraklion 71003,Crete, Greece
Radiologic evaluation may be needed during pregnancy to assess
commoncauses of acute abdominal or thoracic pain. Accidental
irradiation ofpregnant women from radiologic examinations may occur
during theearly postconception weeks. In each case, there has been
a growingconcern about radiation exposure which invokes a great
anxiety for thepregnant patient as well as the treating doctor and
may probably lead tothe unnecessary termination of pregnancy.
However, conceptus dosesbelow 100 mGy should not be considered a
reason for termination. Whilesuch a high-level exposure rarely
occurs during a single medical diag-nostic procedure, the
estimation of conceptus radiation dose is essentialto determine
radiogenic risks to the unborn child and inform theoncoming
mother.Several methods have been developed to estimate conceptus
radiationdose in pregnant woman who undergo radiographic,
uoroscopic anduoroscopically guided interventional procedures.
These methods usethermoluminescence dosimeters along with
anthropomorphic phantoms,which represent pregnant patients at
various gestational stages. Compu-tational methods, which are based
on the Monte Carlo transportation codeas well as mathematical
phantoms have also been applied to estimateconceptus radiation dose
in radiologic procedures. An advantage of thelatter methods is that
they may take into account the somatometriccharacteristic of the
pregnant patients, such as body size, perimeter of theabdomen and
conceptus location.A literature review on the methodologies applied
to estimate conceptusradiation dose in pregnant patient who undergo
diagnostic radiologicalprocedures is presented.
HOW TO ESTIMATE CONCEPTUS DOSE FROM CT EXAMINATIONS
Kostas Perisinakis. Department of Medical Physics, Faculty of
Medicine, POBox 2208, University of Crete, Iraklion 71003, Crete,
Greece
The utilization of computed tomography (CT) in pregnant patients
hasincreased in recent years, following the same trend observed for
non-pregnant patients. In case of a pregnant patient subjected to
CT exposure,
dica 30S1 (2014)apart from the risk for carcinogenesis to the
expecting mother, there is alsoconcern about the teratogenic and
carcinogenic effects of ionizing
-
Abstracts / Physica Medica 30S1 (2014) 11radiation to the
developing conceptus. To estimate the radiogenic risks foran
exposed conceptus to be used in risk benet analysis for a certain
CTexamination, the accurate determination of absorbed dose to
theconceptus is prerequisite.CT exposures of pregnant patients may
be categorized in three typescorresponding to conceptus a) entirely
excluded, b) partially includedand c) entirely included in the
primarily exposed body region. Thiscategorization is associated
with the size of conceptus at the time ofexposure. As gestation
progresses, conceptus size is increased andtherefore, partial
conceptus exposures may occur with increasedpossibility.Several
methods have been proposed in literature for the determinationof
conceptus dose from CT exposures such as a) the use of the
computedtomography CT dose index (CTDI), b) the IMPACT CT Patient
DosimetryCalculator, c) formulas and relevant data provided in the
literature, d)Monte Carlo simulation with standard anthropomorphic
mathematicalphantoms simulating pregnant patients at different
gestational stagesand e) the IMPACT MC dosimetry tool. Some methods
are limited to the1st trimester of pregnancy while others may be
used in all gestationalstages. Some methods may be used only in
case of entire or partial directexposure of conceptus while others
may be also used in case conceptusis not primarily exposed.
Applicability of the above methods in associ-ation with
z-overscanning effect and the use of adaptive section colli-mation,
the use of automatic exposure control and the use of
iterativereconstruction algorithms will also be discussed. The pros
and cons ofthe above methods regarding accuracy, applicability,
required equip-ment and cost will be discussed and guidelines will
be providedregarding the appropriate use of available methods to
estimateconceptus dose in case of intentional or inadvertent CT
exposure of apregnant patient.
OCCUPATIONAL EXPOSURE OF PREGNANT PERSONNEL (REVIEWCOURSE TALK
FOR THE CONCERT PROJECT)
John Stratakis PhD, Kostas Perisinakis PhD, Georgia Solomou MSc,
JohnDamilakis PhD *. Department of Medical Physics, Faculty of
Medicine, POBox 2208, University of Crete, Iraklion 71003, Crete,
Greece
Development of interventional radiology (IR) has been
accompanied by asignicant concern for the safety of the staff
involved in interventionalprocedures, since patient and staff doses
in the IR laboratory may beincreased because of case difculty,
patient condition, and operatorsexperience. Many researchers have
pointed out issues of interest withinthe optimization of radiation
protection that included assessment of doseand risks of
interventional laboratory personnel focused mainly on radi-ation
protection on cardiological, orthopedic and angiographic
procedures.Information about conceptus occupational exposure during
IR proceduresstill remains limited.An anthropomorphic phantomwas
exposed at projections commonly usedin IR procedures. An extended
range of combinations of tube voltage andbeam ltration were used.
For the measurement of scattered air-kerma,the area relative to the
sides