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1Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Basic Film DosimetryIndra J. DasIndra J. Das
University of Pennsylvania, Philadelphia, PA
CheeChee--WaiWai ChengChengArizona Oncology Center, Tucson,
AZArizona Oncology Center, Tucson, AZ
SujathaSujatha PaiPaiState University of New York, State
University of New York, Stony Brook, NY
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Basic Film Basic Film DosimetryDosimetry
WhatWhat is a film?is a film?
WhyWhy to use film ?to use film ?
HowHow to use film?to use film?
WhereWhere to use film?to use film?
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Historical PerspectiveHistorical Perspective18261826 Joseph
Joseph NiepceNiepce First PhotographFirst Photograph
18361836 J. M.J. M. DaguerreDaguerre Concept of developerConcept
of developer
18891889 Eastman KodakEastman Kodak Cellulose nitrate base for
emulsionCellulose nitrate base for emulsion
18901890 Hurter &Hurter &DriffieldDriffield Defined the
term optical densityDefined the term optical density
18951895 RoentgenRoentgen First RadiographFirst Radiograph
18961896 Carl Carl SchlussnerSchlussner First glass plate for
radiographyFirst glass plate for radiography
19131913 KodakKodak Film on Cellulose nitrate baseFilm on
Cellulose nitrate base
19181918 KodakKodak Double emulsion filmDouble emulsion film
19331933 DupontDupont XX--ray film with blue baseray film with
blue base
19421942 PakoPako Automatic film processorAutomatic film
processor
19601960 DupontDupont Polyester base introducedPolyester base
introduced
19651965 KodakKodak Rapid film processingRapid film
processing
19721972 KodakKodak XTL and XV film for therapyXTL and XV film
for therapy
19831983 FujiFuji Computed radiography systemComputed
radiography system
19941994 3M3M Dry process laser imagingDry process laser
imaging
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Film Film DosimetryDosimetrySilver halides Silver halides
Radiographic filmRadiographic filmAvailable in various
sizesAvailable in various sizesRadiation range (Radiation range
(mGymGy--GyGy))Wet chemical processingWet chemical processingStrong
energy dependenceStrong energy dependenceDensitometerDensitometer--
anyany
Self DevelopingSelf DevelopingRadiochromicRadiochromic, ,
Gafchromic Gafchromic filmfilmRelatively smaller film (10x10
cmRelatively smaller film (10x10 cm22))Radiation range (Radiation
range (GyGy--100Gy)100Gy)No processingNo processingLittle energy
dependenceLittle energy dependenceDensitometerDensitometer--
Specialized (light sensitive)Specialized (light sensitive)
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Radiochromic Film
NiroomandNiroomand--Rad Rad et al, et al, Radiochromic
Radiochromic film film dosimetry: Recommendations of AAPM
dosimetry: Recommendations of AAPM Radiation Therapy Committee Task
group Radiation Therapy Committee Task group 55, Med. Phys. 25(11),
209355, Med. Phys. 25(11), 2093--2115, 19982115, 1998
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Radiographic FilmRadiographic Film Base (Cellulose nitrate or
Polyester) (typically 200 Base (Cellulose nitrate or Polyester)
(typically 200 m)m) Emulsion (10Emulsion (10--20 20 m; 2m; 2--5
mg/cm5 mg/cm33))
Gelatin (derivative from bone)Gelatin (derivative from bone)
grain (size: 0.1grain (size: 0.1 --3 3 m diameter)m diameter)
AgBrAgBr (cubic crystal with lattice distance of 28 nm(cubic
crystal with lattice distance of 28 nm
AgIAgI
KIKI
There are 10There are 1099--10101212 grains/cmgrains/cm22 in xin
x--ray filmsray films
CoatingCoating
Very sensitive which may determine X & Y Very sensitive
which may determine X & Y direction uniformitydirection
uniformity
BaseBaseEmulsionEmulsion
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2Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Photographic ProcessPhotographic Process
Silver halides (Silver halides (AgBrAgBr,, AgClAgCl,, AgIAgI) )
are sensitive to radiation.are sensitive to radiation.
Radiation event (latent image) Radiation event (latent image)
can be magnified by a billion fold can be magnified by a billion
fold (10(1099 ) with developer.) with developer.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Emulsion of Film/RadiographEmulsion of Film/RadiographThe heart
of film is emulsion which contains grains The heart of film is
emulsion which contains grains
(crystals of silver halides) in gelatin(crystals of silver
halides) in gelatin
Gelatin is suitable due toGelatin is suitable due to
it keeps grains well dispersedit keeps grains well dispersed
it prevents clumping and it prevents clumping and sedimentation
of grains sedimentation of grains
it protects the unexposed grains it protects the unexposed
grains from reduction by a developerfrom reduction by a
developer
it allows easy processing of it allows easy processing of
exposed grainsexposed grains
it is neutral to the grains in it is neutral to the grains in
terms of fogging, loss of terms of fogging, loss of
sensitivitysensitivity
Electron micrograph of grain in gelatinElectron micrograph of
grain in gelatin
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Film ProcessingFilm ProcessingDeveloping Developing
[([(MetolMetol; methyl; methyl--pp--aminophenol sulphateaminophenol
sulphate oror
PhenidonePhenidone; 1phenol 3pyrazolidone)]; 1phenol
3pyrazolidone)]
Converts all AgConverts all Ag++ atoms to Ag. The latent atoms
to Ag. The latent image Ag image Ag ++ are developed much more are
developed much more rapidly.rapidly.
Stop BathStop Bath
dilute acetic acid stops all reaction and dilute acetic acid
stops all reaction and further developmentfurther development
Fixer, Hypo Fixer, Hypo (Sodium(Sodium
ThiosulphateThiosulphate))
it dissolves all undeveloped grains.it dissolves all undeveloped
grains.
WashingWashing
DryingDryingDas/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Latent imageLatent imageThe change which causes the grains to be
The change which causes the grains to be
rendered developable on exposure is rendered developable on
exposure is considered to be the formation of latent image.
considered to be the formation of latent image.
It is composed of an aggregate of a few silver It is composed of
an aggregate of a few silver atoms (4atoms (4--10).10).
On average 1000 Ag atoms are formed per xOn average 1000 Ag
atoms are formed per x--ray quantum absorbed in a grain. ray
quantum absorbed in a grain.
Gurney & Mott provided a clear picture of Gurney & Mott
provided a clear picture of latent imagelatent image
Ref.Ref. HerzHerz, 1969, 1969
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
GrainGrain
SilverSilver
SpeckSpeck
XX--rayray
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Hurter &Hurter & DriffieldDriffield (1890)(1890)Optical
Density (OD)Optical Density (OD)
OD= logOD= log1010(Io/I)(Io/I)
OD=logOD=log1010 (T) where T is transmittance(T) where T is
transmittance
T=T=eeanan
a= average area/grain; n is number of exposed grains/cma=
average area/grain; n is number of exposed grains/cm22; ; N is
number of grains/cmN is number of grains/cm22
OD = log (T) = an logOD = log (T) = an log1010e = 0.4343 ane =
0.4343 an
n/N = an/N = a ; ; where where electron fluenceelectron
fluence
OD = 0.4343 aOD = 0.4343 a22NN
OD is proportional to OD is proportional to and hence dose and
and hence dose and square of grain areasquare of grain area..
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3Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Characteristic curveCharacteristic curveH&D CurveH&D
Curve
Gradient, gamma, slope = Gradient, gamma, slope =
(D(D22--DD11)/Log(E)/Log(E22/E/E11))Speed (sensitivity)= Speed
(sensitivity)= 1/Roentgens for OD equal to unity1/Roentgens for OD
equal to unityLatitude (Contrast): Latitude (Contrast): range of
log exposure to give range of log exposure to give
an acceptable density rangean acceptable density range
Log (exposure)Log (exposure)
Opt
ical
Den
sity
Op t
ical
Den
sity
basebase
slopeslope
shouldershoulder
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
5.55.500 0.50.5 1.01.0 1.51.5 2.02.0 2.52.5 3.03.0 3.53.5 4.04.0
4.54.5 5.05.000
0.50.5
1.01.0
1.51.5
2.02.0
2.52.5
3.03.0
3.53.5
4.04.0
Opt
ical
Den
sity
Opt
ical
Den
sity
Log Relative ExposureLog Relative Exposure
Haus Haus et al 1997et al 1997
Characteristic curves of various filmCharacteristic curves of
various film
DxDx
RxRx
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Characteristics of Commercially Available Radiographic
FilmsCharacteristics of Commercially Available Radiographic
Films
FilmFilm Optimum DoseOptimum Dose GammaGamma LatitudeLatitudeCEA
TVSCEA TVS 6060 4.44.4 0.350.35
CEA TLFCEA TLF 1919 3.63.6 0.40.4
AgfaAgfa Ortho STG2Ortho STG2 4.74.7 3.63.6 0.40.4
Agfa Agfa HTAHTA 3.53.5 2.72.7 0.30.3
Agfa Agfa RP1RP1 1.51.5 2.62.6 0.50.5
AgfaAgfa MR3MR3 4.24.2 2.12.1 0.60.6
Du PontDu Pont CronexCronex 4.04.0 2.62.6 0.50.5
Du Pont UVDu Pont UV 1.51.5 1.91.9 0.50.5
Fuji MIMAFuji MIMA 6.36.3 2.82.8 0.50.5
Fuji HRGFuji HRG 6.26.2 2.82.8 0.50.5
Kodak XVKodak XV 5050 2.92.9 0.60.6
Kodak TL 44 2.02.0 0.50.5
Kodak XLKodak XL 1.71.7 2.02.0 0.60.6
Kodak Kodak MinRMinR 12.312.3 1.81.8 0.40.4
Kodak TMATGKodak TMATG 2.52.5 2.52.5 0.40.4
Kodak OrthoKodak Ortho 4.54.5 2.32.3 0.40.4
Konica MGHKonica MGH 5.05.0 2.72.7 0.40.4
Roberts, BJR, 69, 70Roberts, BJR, 69, 70--71, 199671, 1996
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TabularTabular
CubicCubic
3D3D
Eastman Kodak Company, 2001Eastman Kodak Company, 2001
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Kodak, XV CEA, TVS
Cheng & Das, Med. Phys. 23, 1225, 1996Cheng & Das, Med.
Phys. 23, 1225, 1996
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Kodak MinKodak Min--RR Kodak ECLKodak ECL
Unusual silver halide grain morphologiesUnusual silver halide
grain morphologiesHausHaus, 2001, 2001
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4Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Developed grain showing filamentary silver
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 1.01.0 2.02.0 3.03.0 4.04.0 5.05.0
Optical DensityOptical Density
00
1.01.0
2.02.0
3.03.0
4.04.0
5.05.0
6.06.0
7.07.0
Con
trast
Con
trast
RangeRange
Optimum Optical DensityOptimum Optical Density
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
8484 8686 9090 9292 9494 9696 9898 100100 1021028888
0.40.4
0.60.6
0.80.8
1.01.0
1.21.2
1.41.4
1.61.6
Developer Temperature (degree F)Developer Temperature (degree
F)
Opt
ical
Den
sity
Opt
ical
Den
sity
DupontDupontKodak MRMKodak MRMFujiFujiKodak MR5Kodak MR5
Temperature Dependence of Various FilmsTemperature Dependence of
Various Films
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Bogucki Bogucki et al, Med.Phys., 24, 581, 1997et al, Med.Phys.,
24, 581, 1997
Cha
nge
in O
D p
er D
egre
e Pr
oces
sor T
empe
ratu
reC
hang
e in
OD
per
Deg
ree
Proc
esso
r Tem
pera
ture
(( O
DO
D//
TT ))
9191 9292 9393 9494 9595 9696 9797 9898 9999
0.00.0
.02.02
.04.04
.06.06
.08.08
.10.10
Processor Temperature (degree F)Processor Temperature (degree
F)
Kodak FilmsKodak Films
Min R MMin R M
Ektascan Ektascan HNHN
TT--Mat G/RAMat G/RA
Ektascan Ektascan IRIR
OD=KOD=K00T +KT +K11TT22
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 0.50.5 1.01.0 1.51.5 2.02.0 2.52.5 3.03.0 3.53.5 4.04.0
0.00.0
.02.02
.04.04
.06.06
.08.08
.10.10
Optical DensityOptical Density
Cha
nge
in O
D p
er D
egre
e Pr
oces
sor T
empe
ratu
reC
hang
e in
OD
per
Deg
ree
Proc
esso
r Tem
pera
ture
(( O
DO
D//
TT ))
Kodak FilmsKodak Films
Min R MMin R M
Ektascan Ektascan HNHN
TT--Mat G/RAMat G/RA
Ektascan Ektascan IRIR
Bogucki Bogucki et al, Med.Phys., 24, 581, 1997et al, Med.Phys.,
24, 581, 1997
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
91 F91 F33 C33 C
95 F95 F35 C35 C
99 F99 F37 C37 C
103 F103 F39 C39 C
0.160.16
0.180.18
0.200.20
0.220.22
2.82.8
3.03.0
3.23.2
3.43.4
3.63.6
--2020
00
2020
4040
BaseBase
++
FogFog
ContrastContrastAverageAverageGradientGradient
SpeedSpeed% change% change
TemperatureTemperature
Standard Processing CycleStandard Processing Cycle
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5Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Various types of plots for film responseVarious types of plots
for film responseO
ptic
alO
ptic
alD
ensi
tyD
ensi
ty
Log (exposure)Log (exposure)
(a)(a)
Opt
ical
Opt
ical
Den
sity
Den
sity
Exposure, DoseExposure, Dose
(c)(c)
Log
(Op t
ical
Log
(Op t
ical
Den
sity
)D
ensi
ty)
Log (exposure, dose)Log (exposure, dose)
(b)(b)
OpticalOptical DensityDensity
Expo
sure
, Do s
eEx
posu
re, D
o se
(d)(d)
DXDXTxTx
H&
DH
&D
Con
trast
Con
trast
Sens
itom
etric
Sens
itom
etric
Cal
ibra
tion
Cal
ibra
tion
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
D = DoseD = DoseDr = Dose rateDr = Dose rateE = EnergyE =
EnergyT = type of radiation (xT = type of radiation (x--rays,
electrons etc)rays, electrons etc)d = depth of measurementd = depth
of measurementFS= Field SizeFS= Field Size = Orientation: parallel
or perpendicular= Orientation: parallel or perpendicular
Optical Density = OD(D, Dr, E, T, d, FS, Optical Density = OD(D,
Dr, E, T, d, FS, ))
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Film Film Dosimetry Dosimetry in therapyin therapy
1954,1954, GrankeGranke et al; tissue dose studies with 2 MV xet
al; tissue dose studies with 2 MV x--raysrays
1969,1969, DutreixDutreix et al; highlights of the problems in
et al; highlights of the problems in film dosimetryfilm
dosimetry
1981, Williamson et al; Provided solution to the film 1981,
Williamson et al; Provided solution to the film dosimetry
problemsdosimetry problems
1996, Cheng & Das; CEA film, better film for 1996, Cheng
& Das; CEA film, better film for dosimetrydosimetry
1997, Burch et al & 1997, Burch et al & YeoYeo et al;
lateral scatter filteringet al; lateral scatter filtering
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Optimum propertiesOptimum properties
Linear with dose (dose dependence)Linear with dose (dose
dependence)
Linear with dose rate (dose rate Linear with dose rate (dose
rate independence)independence)
Radiation type (independent of photon and Radiation type
(independent of photon and electron)electron)
Energy independentEnergy independent Uniformity in x & y
(coating artifact)Uniformity in x & y (coating artifact)
Processing conditionProcessing condition
FadingFading Delayed processingDelayed processing Atmospheric
condition, temperature, humidityAtmospheric condition, temperature,
humidity
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Exposure, RExposure, R
Opt
ical
Opt
ical
Den
sity
Den
sity
1010--22 1010--11 101000 101011 101022 101033 101044
10105500
11
22
33
44
55
66
0.033R/sec0.033R/sec
1.31R/sec1.31R/sec
62R/sec62R/sec
1100R/sec1100R/sec
Dose Rate DependenceDose Rate Dependence
Ehrlich, J.Opt.Soc.Am. 46,801, 1956Ehrlich, J.Opt.Soc.Am.
46,801, 1956Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 1010 2020 3030 4040 5050 6060 7070 8080Dose (cGy)Dose
(cGy)
00
0.50.5
1.01.0
1.51.5
2.02.0
2.52.5
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
28 28 keVkeV 44 44 keVkeV
79 79 keVkeV
97 97 keVkeV
142 142 keVkeV
1.711.71 MeVMeV
Muench Muench et al, Med. Phys. 18, 769, 1991et al, Med. Phys.
18, 769, 1991
Kodak XV FilmKodak XV Film
Energy Dependence of Radiographic FilmEnergy Dependence of
Radiographic Film
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6Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
1010 100100 10001000
0.10.1
1.01.0
1010
100100
unfilteredunfiltered
filteredfiltered
Photon Energy, (Photon Energy, (keVkeV))
Rel
ativ
e re
spon
seR
elat
ive
resp
onse
RR.H. .H. HerzHerz, The photographic action, 1969, The
photographic action, 1969
Energy response balancing with filter Energy response balancing
with filter used in personnel monitoringused in personnel
monitoring
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 2020 4040 6060 8080 100100
Dose (cGy)Dose (cGy)
0.00.0
1.01.0
2.02.0
3.03.0
4.04.0
5.05.0
Opt
ical
Den
sity
Opt
ical
Den
sity
Energy Dependence of CEA TVS filmEnergy Dependence of CEA TVS
film
CsCs--137137CoCo--60604 MV4 MV6 MV6 MV10 MV10 MV18 MV18 MV
Cheng & Das, Med. Phys. 23, 1225, 1996Cheng & Das, Med.
Phys. 23, 1225, 1996
Gamma raysGamma rays XX--raysrays
ODOD = 0.054 Dose= 0.054 Dose
ODODxx = 0.047 Dose= 0.047 Dose
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
0055 1010
5050
100100
Depth (cm)Depth (cm)
Dos
e (%
)D
ose
(%)
Air gapAir gap FilmFilm
00
0.250.25
0.500.500.75 mm0.75 mm
Effect of film air gap on depth doseEffect of film air gap on
depth dose
Dutreix Dutreix et al, Ann NY et al, Ann NY Acad SciAcad Sci,
161, 33, 1969, 161, 33,
1969Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Air gapAir gap FilmFilm
0055 1010
5050
100100
Depth (cm)Depth (cm)
Dos
e (%
)D
ose
(%)
00
22
5 mm5 mm
Effect of film misalignment on depth doseEffect of film
misalignment on depth dose
Dutreix Dutreix et al, Ann NY et al, Ann NY Acad SciAcad Sci,
161, 33, 1969, 161, 33, 1969
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Dutreix Dutreix et al, Ann NY et al, Ann NY Acad SciAcad Sci,
161, 33, 1969, 161, 33, 1969
Effect of film under alignment on depth doseEffect of film under
alignment on depth dose
55 1010
Depth (cm)Depth (cm)
Air gapAir gap FilmFilm
00
5050
100100
Dos
e (%
)D
ose
(%)
0 mm0 mm
447 mm7 mm
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Methods to eliminate problems with FilmMethods to eliminate
problems with Film
To eliminate air trapped inside jacket, vacuum To eliminate air
trapped inside jacket, vacuum packing could be used (CEA
film).packing could be used (CEA film).
To keep identical position and pressure, RMI To keep identical
position and pressure, RMI sells film cassettes for dosimetry.sells
film cassettes for dosimetry.
Use film in water as suggested by van Use film in water as
suggested by van BattumBattumet al, et al,
RadiotherRadiother..OncolOncol. 34, 152, 1995. 34, 152, 1995
Special phantom; Special phantom; BovaBova, Med. Dos. 15, 83,
1990, Med. Dos. 15, 83, 1990
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7Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
CEA Films (TLF, TVS)CEA Films (TLF, TVS)
00 2020 4040 6060 8080 100100
Dose (cGy)Dose (cGy)
Opt
ical
Den
sity
Opt
ical
Den
sity
00
11
22
33
44Kodak TLKodak TL
120120
CEA TLFCEA TLFCEA TVSCEA TVS
Kodak XVKodak XV
Cheng & Das, Med. Phys. 23, 1225, 1996Cheng & Das, Med.
Phys. 23, 1225,
1996Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
OD Vs DoseOD Vs Dose
PDDPDD = [= [a+b(OD) +c(OD)a+b(OD) +c(OD)22]]dd // [a+b(OD)
+c(OD)[a+b(OD) +c(OD)22]]maxmax
OAR=OAR=[[a+b(OD) +c(OD)a+b(OD) +c(OD)22]]x x // [a+b(OD)
+c(OD)[a+b(OD) +c(OD)22]]caxcax
D = m(OD) thenD = m(OD) then
DD22/D/D11 = OD= OD22/OD/OD11
For limited range and linear filmFor limited range and linear
film
Dose = a+b(OD) +c(OD)2
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
OD depth and field size dependentOD depth and field size
dependent
OD(D, d) = ODOD(D, d) = ODss[1[1--1010--(d)D(d)D]]
(d) = (d) = (d(dmm)[1+)[1+(d(d--ddmm)])] = 0.0182= 0.0182
CoCo--6060 = 0.0150= 0.0150 4 MV4 MV = 0.0062= 0.0062 10 MV10
MV
Williamson et al , Med. Phys. 8, 94, 1981Williamson et al , Med.
Phys. 8, 94, 1981
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Depth (cm)Depth (cm)
0.80.8
0.90.9
1.01.0
1.11.1
1.21.2
1.31.3
1.41.4
00 55 1010 1515 2020 2525 3030
Film
Den
sity
Film
Den
sity
Williamson et al , Med. Phys. 8, 94, 1981Williamson et al , Med.
Phys. 8, 94, 1981
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002Williamson et al
, Med. Phys. 8, 94, 1981Williamson et al , Med. Phys. 8, 94,
1981
3030
4040
5050
6060
7070
8080
9090100100
110110120120
FilmFilmIon ChamberIon Chamber
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
3030
4040
5050
6060
7070
9595100100
9090
8080 FilmFilmIon ChamberIon Chamber
Williamson et al , Med. Phys. 8, 94, 1981Williamson et al , Med.
Phys. 8, 94, 1981
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8Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Sensitivity of film to scatterSensitivity of film to
scatterDepth and field size dependence of ODDepth and field size
dependence of OD
Van Van Battum Battum et al, film in wateret al, film in
water
Burch et al, lead filterBurch et al, lead filter
Yeo Yeo et al , Lead filteret al , Lead filter
Skyes Skyes et al, against filter methodet al, against filter
method
although scatter filtering method appears to have although
scatter filtering method appears to have the desired effect it
seems intuitively wrong to the desired effect it seems intuitively
wrong to introduce a high Z filter in order to make an introduce a
high Z filter in order to make an inadequate dosimeter, film,
behave as if it is water inadequate dosimeter, film, behave as if
it is water equivalentequivalent
Suchowerska Suchowerska et al MC simulation to prove scatter as
et al MC simulation to prove scatter as a problema problem
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 55 1010 1515 2020 2525
9494
9696
9898
100100
102102
104104
106106
108108
4x44x410x1010x10
20x2020x20
30x3030x30
Depth (cm)Depth (cm)
Opt
ical
Den
sity
(Nor
mal
ized
)O
ptic
al D
ensi
ty (N
orm
aliz
ed)
Van Van Battum Battum et al , et al , Radiother OncolRadiother
Oncol, 34, 152, 1995, 34, 152, 1995
Effect of depth and field size on ODEffect of depth and field
size on OD
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 22 44 66 20201818161614141212101088
Depth (cm)Depth (cm)
Rel
ativ
e D
ose
(%)
Rel
ativ
e D
ose
(%)
00
2020
4040
6060
8080
100100
4x44x410x1010x10
20x2020x20
Van Van Battum Battum et al , et al , Radiother OncolRadiother
Oncol, 34, 152, 1995, 34, 152, 1995
FilmFilmIon ChamberIon Chamber
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
2
34
5
6
23 4
56
Scattered photon, h
Primary Photon, h
Scattered electrons
Compton Scattering
11
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Yeo Yeo et al Med. Phys. 24, 1943, 1997et al Med. Phys. 24,
1943, 1997Burch et al, Med. Phys. 24, 775, 1997Burch et al, Med.
Phys. 24, 775, 1997
FilmFilm Lead filterLead filter
PhotonPhoton
Parallel film OrientationParallel film Orientation
Movable positionMovable position
X, X, 6, 12, 19 mm6, 12, 19 mmt= 0.15, 0.30,t= 0.15, 0.30,.0.46,
0.76 mm.0.46, 0.76 mm
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002JuJu et al, Med.
Phys., 29, 351et al, Med. Phys., 29, 351--355, 2002355, 2002
-
9Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
JuJu et al, Med. Phys., 29, 351et al, Med. Phys., 29, 351--355,
2002355, 2002
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
1.21.2
1.01.0
0.80.8
0.60.6
0.40.4
0.20.2
--1010 --55 00 55 1010Distance from central axis (cm)Distance
from central axis (cm)
Rel
ativ
e do
se (r
atio
)R
elat
ive
dose
(rat
io)
Film no filterFilm no filterFilm with filterFilm with filterIon
ChamberIon Chamber
Ju Ju et al, Med. Phys., 29, 351et al, Med. Phys., 29, 351--355,
2002355, 2002
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 22 44 66 88
Energy (Energy (MeVMeV))
0.00.0
2.02.0
4.04.0
6.06.0
8.08.0
10.010.0
Rel
ativ
e Fl
uenc
e (%
)R
elat
ive
Flue
nce
(%)
MC simulation of photon spectrum at various depthsMC simulation
of photon spectrum at various depths
30 cm30 cm
10 cm10 cm
1.5 cm1.5 cm
Suchowerska Suchowerska et al, Phys. Med. Biol. 44, 1755, 1999et
al, Phys. Med. Biol. 44, 1755,
1999Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
00 55 1010 1515 2020 2525 3030 3535 404000
2020
4040
6060
8080
100100
120120
140140
160160
180180
200200
Dos
e (
Do s
e ( c
Gy
cGy ))
Depth (cm)Depth (cm)
X=0 mmX=0 mm
Ion chamberIon chamber
X=6 mmX=6 mm
X=12 mmX=12 mm
4 MV, 25x25 cm4 MV, 25x25 cm220.76 mm 0.76 mm PbPb
Burch et al, Med. Phys., 24, 775, 1997Burch et al, Med. Phys.,
24, 775, 1997
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
No No PbPb
Ion ChamberIon Chamber
Film+.46 mm Film+.46 mm PbPb
Depth (cm)Depth (cm)00 55 1010 1515 2020 2525 3030 3535 4040
00
2020
4040
6060
8080
100100
120120
4 MV, 25x25 cm4 MV, 25x25 cm22
No No PbPb
Film+.46 mm Film+.46 mm PbPb
Ion ChamberIon Chamber
Burch et al, Med. Phys., 24, 775, 1997Burch et al, Med. Phys.,
24, 775, 1997
00 55 1010 1515 2020 2525 3030 3535 404000
2020
4040
6060
8080
100100
120120
Dos
e (
Dos
e ( c
Gy
cGy ))
Depth (cm)Depth (cm)
4 MV, 6x6 cm4 MV, 6x6 cm22
Effect of Effect of Pb Pb filter on depth dosefilter on depth
dose
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002Danciu Danciu et
al, Med. Phys. 28, 972, 2001et al, Med. Phys. 28, 972, 2001
2.02.000 0.50.5 1.01.0 1.51.5
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
0.00.0
1.01.0
1.51.5
2.02.0
2.52.5
3.03.0C0C0--6060KodakKodak
Dose (Dose (GyGy))
0.5g/cm0.5g/cm334 g/cm4 g/cm339 g/cm9 g/cm33
DepthDepth
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
Dose (Dose (GyGy))00 0.50.5 1.01.0 1.51.5
0.00.0
1.01.0
1.51.5
2.02.0
2.52.5
3.03.06 MV6 MVKodakKodak
0.5g/cm0.5g/cm334 g/cm4 g/cm339 g/cm9 g/cm33
DepthDepth
2.02.0
00 0.50.5 1.01.0 1.51.50.00.0
1.01.0
1.51.5
2.02.0
2.52.5
3.03.045 MV45 MVKodakKodak
0.5g/cm0.5g/cm334 g/cm4 g/cm339 g/cm9 g/cm33
DepthDepth
2.02.000 0.50.5 1.01.0 1.51.50.00.0
1.01.0
1.51.5
2.02.0
2.52.5
3.03.018 MV18 MVKodakKodak
0.5g/cm0.5g/cm334 g/cm4 g/cm339 g/cm9 g/cm33
DepthDepth
2.02.0
Dose (Dose (GyGy)) Dose (Dose (GyGy))
Sensitometric Sensitometric curves for 15x15 cmcurves for 15x15
cm22 fieldfieldwith perpendicular film exposurewith perpendicular
film exposure
-
10
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
Depth (cm)Depth (cm)1414 161600 22 44 66 88 1010 1212
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
1.01.0
1.51.5
2.02.0
2.52.5
3.03.0
3.53.5CoCo--6060
AgfaAgfa
KodakKodak
ParallelParallelPerpendicularPerpendicular
1414 161600 22 44 66 88 1010 1212
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
1.01.0
1.51.5
2.02.0
2.52.5
3.03.0
3.53.515 MV15 MVAgfaAgfa
KodakKodak
ParallelParallelPerpendicularPerpendicular
Depth (cm)Depth (cm)
1414 161600 22 44 66 88 1010 12121.01.0
1.51.5
2.02.0
2.52.5
3.03.0
3.53.56 MV6 MVAgfaAgfa
KodakKodak
ParallelParallelPerpendicularPerpendicular
Depth (cm)Depth (cm)
Net
Opt
ical
Den
sity
Net
Opt
ical
Den
sity
1414 161600 22 44 66 88 1010 12121.01.0
1.51.5
2.02.0
2.52.5
3.03.0
3.53.545 MV45 MV
KodakKodak
ParallelParallelPerpendicularPerpendicular
Depth (cm)Depth (cm)
Danciu Danciu et al, Med. Phys. 28, 972, 2001et al, Med. Phys.
28, 972, 2001Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Net Optical Density0 0.2 0.4 0.6 0.8 1.0 1.2
0
5
10
15
20
25
30
Dos
e (c
Gy)
6x6, 5 cm depth6x6, 5 cm depth25x25, 5 cm depth25x25, 5 cm
depth6x6, 15 cm depth6x6, 15 cm depth25x25, 15 cm depth25x25, 15 cm
depth
Sykes et al, Med.Phys., 26, 329, 1999Sykes et al, Med.Phys., 26,
329, 1999
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
eewweewweeww
PP PP
eeww eewweeff
filmfilm# # eeww
-
11
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
403530252015100.82
0.84
0.86
0.88
0.90
0.92
0.94
0.96
0.98
1.00
1.02
1.04
1.06
V-1
V-3V-2
CEA-1
V-4
CEA-2
V-5
Variation of cone factor, St, using film
Cone Diameter (mm)
Con
e Fa
ctor
(St)
Das et al, J. Das et al, J. RadiosurgRadiosurg. 3, 177, 2000. 3,
177, 2000Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
0 50 100 1500.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0 50 100 1500.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Opt
ical
den
sity
Kodak
B C D E Wellhfer
Dose (cGy)Dose (cGy)
CEA
Bos et al, Med. Phy. 29 (in press) 2002
Film Scanner Light source Wavelength/color
Konica KFDR-S diode-laser 780 nmMultidata 9721 diode-laser
redVidar VXR-12 standard fluorescent light whiteWellhfer WD 102
infrared diode 950 nmX-rite Model 301 tungsten halogen bulb bluish
white
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002Bos Bos et al,
Med. et al, Med. PhyPhy. 29 (in press) 2002. 29 (in press) 2002
0 20 40 60 80 1000
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Dose (cGy)
TTA TAA PPA PAA
Opt
ical
den
sity
0 20 40 60 80 1000
0.5
1.0
1.5
2.0
2.5
3.0
3.5
TAA PAA AAA
Opt
ical
den
sity
0 20 40 60 80 1000
0.5
1.0
1.5
2.0
2.5
3.0
3.5Dose (cGy)
C
B
A
Kodak
TTT TTA PPP PPA AAA
Opt
ical
den
sity
Dose (cGy)
Effect Comparison OD difference at 50cGy
Kodak CEA
Batchcomposition
TAA vs.AAA
14% 9%
PAA vs.AAA
20% 2%
Irradiationconditions
TTA vs.TAA
2% 5%
PPA vs.PAA
2% 5%
Filmprocessing
TTT vs.TTA
11% 31%
PPP vs. PPA 38% 16%Combinedeffect
TTT vs.AAA
20% 32%
PPP vs. AAA 13% 13%
Interinstitutional Interinstitutional Variation in ODVariation
in OD
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Advantage of film dosimetryAdvantage of film dosimetry
Unrivaled spatial distribution of dose or energy Unrivaled
spatial distribution of dose or energy imparted.imparted.
Repeated reading of same film: permanent recordRepeated reading
of same film: permanent record
22--D distribution with single exposureD distribution with
single exposure
Small detector sizeSmall detector size
Wide availability: Kodak,Wide availability: Kodak, AgfaAgfa,
Fuji, Dupont, CEA , Fuji, Dupont, CEA
Large area dosimetry: Especially for electron beamLarge area
dosimetry: Especially for electron beam
Linearity of dose (over a short dose range, OD can Linearity of
dose (over a short dose range, OD can be treated linear with dose
for most films)be treated linear with dose for most films)
Dose rate independenceDose rate independence
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Film dosimetry Film dosimetry -- ConcernsConcernsThe main
problem in using radiographic The main problem in using
radiographic
film is the dependence of optical density film is the dependence
of optical density (OD) on: (OD) on: Strong energy dependence (high
sensitivity to Strong energy dependence (high sensitivity to
low energy photons due to photoelectric low energy photons due
to photoelectric interactions in grainsinteractions in grains));
;
Film plane orientation with respect to the Film plane
orientation with respect to the beam direction; beam direction;
Emulsion differences amongst films of Emulsion differences
amongst films of different batches, films of the same batch or
different batches, films of the same batch or even in the same
film; even in the same film;
Densitometer/Digitizer artifacts.Densitometer/Digitizer
artifacts.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
OD depends on:OD depends on: Chemical processing Chemical
processing
developer chemistry and temperaturedeveloper chemistry and
temperature Processing timeProcessing time drying conditionsdrying
conditions
Sensitivity to environmentSensitivity to environment High
temperature & humidity creating fadingHigh temperature &
humidity creating fading Storage stabilityStorage stability
0.050.05--0.1 OD in (60.1 OD in (6--60mR) among various
films60mR) among various films (ref(refSoleimanSoleiman et al
Med.et al Med. PhyPhy. 22, 1691, 1995). 22, 1691, 1995)
Microbiological growth in gelatinMicrobiological growth in
gelatinSolarizationSolarization: At extremely higher doses, OD : At
extremely higher doses, OD
decreasesdecreases
Film dosimetry Film dosimetry -- ConcernsConcerns
-
12
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69 TG69 -- RADIOGRAPHIC FILM FOR RADIOGRAPHIC FILM FOR
MEGAVOLTAGE BEAM DOSIMETRYMEGAVOLTAGE BEAM DOSIMETRY
Film Dosimetry for commissioning and Film Dosimetry for
commissioning and verifying special procedures in
radiotherapy.verifying special procedures in radiotherapy. Enhanced
Dynamic Wedge (EDW) Enhanced Dynamic Wedge (EDW)
Stereotactic Radiosurgery (SRS) Stereotactic Radiosurgery
(SRS)
Intensity Modulated Radiotherapy (IMRT) Intensity Modulated
Radiotherapy (IMRT)
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Disadvantage of film dosimetryDisadvantage of film dosimetry
Chemical processing (except Gafchromic films)Chemical processing
(except Gafchromic films)
OD depends on:OD depends on: developer temperaturedeveloper
temperature drying conditionsdrying conditions
Strong energy dependence (high sensitivity to low Strong energy
dependence (high sensitivity to low energy photons due to
photoelectric interactions in energy photons due to photoelectric
interactions in grainsgrains))
Sensitivity to environmentsSensitivity to environments high
temperature and humidity crating fadinghigh temperature and
humidity crating fading
Storage stabilityStorage stability
0.050.05--0.1 OD in (60.1 OD in (6--60mR) among various 60mR)
among various films films (ref (ref Soleiman Soleiman et al Med. et
al Med. PhyPhy. 22, 1691, 1995). 22, 1691, 1995)
Microbiological growth in gelatinMicrobiological growth in
gelatin
SolarizationSolarization: at extremely higher doses, OD
decreases: at extremely higher doses, OD decreases
Absolute dosimetry is difficultAbsolute dosimetry is
difficult
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Advantage of film dosimetryAdvantage of film dosimetryUnrivaled
spatial distribution of dose or energy Unrivaled spatial
distribution of dose or energy
imparted.imparted.
Repeated reading of same film: permanent Repeated reading of
same film: permanent recordrecord
Wide availability: Kodak,Wide availability: Kodak, AgfaAgfa,
Fuji, Dupont, , Fuji, Dupont, CEA etc.CEA etc.
Large area dosimetry: Especially for electron Large area
dosimetry: Especially for electron beambeam
Linearity of dose (over a short dose range, OD Linearity of dose
(over a short dose range, OD can be treated linear with dose for
most films)can be treated linear with dose for most films)
Dose rate independenceDose rate independence
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69 TG69 RADIOGRAPHIC FILM DOSIMETRYRADIOGRAPHIC FILM
DOSIMETRY
Task group members:Task group members:S. Pai S. Pai
--ChairChair
L. Reinstein L. Reinstein CoCo--ChairChairJ. WilliamsonJ.
Williamson
J. PaltaJ. PaltaK. Lam K. Lam
T. LosassoT. LosassoE. GreinE. Grein
I. DasI. DasJ. DempseyJ. Dempsey
A. OlchA. Olch
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69TG69 Film Dosimetry Film Dosimetry -- IssuesIssues
Film selectionFilm selection Film orientationFilm orientation
Phantom choicePhantom choice Film handlingFilm handling Beam
quality issuesBeam quality issues Film Processor Film Processor
Film Digitizer characteristicsFilm Digitizer characteristics
The primary mission of the task group is to The primary mission
of the task group is to develop guidelines to allow optimal
external develop guidelines to allow optimal external beam dose
measurements.beam dose measurements.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Self developing, turns dark blue soon after irradiationSelf
developing, turns dark blue soon after irradiationNear tissue
equivalent, > 0.1MeV energy independentNear tissue equivalent,
> 0.1MeV energy independent OD increases gradually with time
(logt)
Dependency on temperature during and post irradiation
Dependency on densitometer wavelength and temperature
Sensitivity may vary somewhat across film
Affected by compression, water/humidity, high temperature
Slightly reduced sensitivity at < 0.1MeV
OD increases in UV and fluorescent light
RadiochromicRadiochromic filmfilmNiroomandNiroomand--Rad et al,
Rad et al, Radiochromic Radiochromic film dosimetry: Task group 55,
film dosimetry: Task group 55, Med. Phys. 25(11), 2093Med. Phys.
25(11), 2093--2115, 19982115, 1998
-
13
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
ProcessorsProcessorsUsing the newer automatic processorsUsing
the newer automatic processors
Developer temperature Developer temperature
Processing time Processing time
Chemistry activity of the processorChemistry activity of the
processor
held extremely stable to improve the reproducibility and the
held extremely stable to improve the reproducibility and the
stability of the film density. stability of the film density.
Development of recommendation for the processor Development of
recommendation for the processor acceptance tests and QA.acceptance
tests and QA.
Determination of correction factors for temperature and
Determination of correction factors for temperature and chemical
variations of the processors in general:chemical variations of the
processors in general:
By processing the nonBy processing the non--exposed films (known
density exposed films (known density films) intermixed with the
experiment films and films) intermixed with the experiment films
and calibration films.calibration films.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
DensitometersDensitometers/ Digitizers/ DigitizersVisual type
densitometer (Dobson, Griffith & Visual type densitometer
(Dobson, Griffith &
Harrison, 1926)Harrison, 1926)Photoelectric typePhotoelectric
type light densitometer (wide spectrum)light densitometer (wide
spectrum) Standard:Standard: McBethMcBeth,, XriteXrite, Nuclear
Associate etc, Nuclear Associate etc
Light source coupled with CCD digitizerLight source coupled with
CCD digitizer Fluorescent light source Fluorescent light source
Vidar Vidar VXRVXR--16 Digitizer16 Digitizer LED light source LED
light source -- Howtek MultiRADHowtek MultiRAD 460 Digitizer460
Digitizer
Laser densitometer (single wavelength)Laser densitometer (single
wavelength) LumysisLumysis scanning systemscanning system
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Film
Incident light
Transmitted light
Diffuse
Specular
Double diffuse
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Scanning film Digitizer Artifacts:Scanning film Digitizer
Artifacts:
Drift in OD; warmDrift in OD; warm--up effect of fluorescent
lamp up effect of fluorescent lamp Use first 20Use first 20--30
minutes as warm30 minutes as warm--up timeup time
Scanner spatial distortionScanner spatial distortion Validated
in both dimensions using known test patternsValidated in both
dimensions using known test patterns
Interference artifacts Interference artifacts -- at the
interface of film at the interface of film and the glass plate/film
support.and the glass plate/film support. ((Multiple Multiple
reflection due to changes in the index of reflection due to changes
in the index of refraction)refraction) Use of diffused glass or
antireflective coated glassUse of diffused glass or antireflective
coated glass
ReinsteinReinstein et. al., Dempsey et.al.et. al., Dempsey
et.al.
DigitizersDigitizers
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
-
Digitizer ArtifactsDigitizer Artifacts
GluckmanGluckman, et.al., et.al.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Scanning film Digitizer Artifacts:Scanning film Digitizer
Artifacts: Internal light scatter at OD discontinuities Internal
light scatter at OD discontinuities
introducing OD nonintroducing OD non--linearity linearity
Reduced by applying DFFT (Dempsey et.al)Reduced by applying DFFT
(Dempsey et.al)
Light source/Detector response & linearity Light
source/Detector response & linearity Signal to Noise
ratioSignal to Noise ratio Temporal Noise (electronic noise)
Temporal Noise (electronic noise)
Optimal OD of Optimal OD of
-
14
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
DigitizersDigitizersScanning film Digitizer
Characteristics:Scanning film Digitizer Characteristics: Fast high
resolution 2D scannersFast high resolution 2D scanners Transmission
optical densitometry Transmission optical densitometry Reflection
densitometry Reflection densitometry limited OD range limited OD
range
Spatial resolutionSpatial resolution Pixel dimension 0.34 Pixel
dimension 0.34 0.042mm (720.042mm (72--600 dpi) 600 dpi)
Dynamic rangeDynamic range 0 to upper limit of 2.5 to 4.0 OD0 to
upper limit of 2.5 to 4.0 OD
Scanner output Scanner output OD measurement (OD measurement
(>> 12 bit ADC)12 bit ADC) Transmission measurement and then
converted to OD Transmission measurement and then converted to
OD
((>>14 bit ADC)14 bit ADC)
Dempsey et.al. Dempsey et.al.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Optimal OD Optimal OD DigitizersDigitizers
ReinsteinReinstein et. al.et. al.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69 TG69 -- RADIOGRAPHIC FILM FOR RADIOGRAPHIC FILM FOR
MEGAVOLTAGE BEAM DOSIMETRYMEGAVOLTAGE BEAM DOSIMETRY
Enhanced Dynamic WedgeEnhanced Dynamic
WedgeCommissioningCommissioning
EDW profiles are obtained in a single exposure EDW profiles are
obtained in a single exposure using a multiple film loaded
phantomusing a multiple film loaded phantom
Concern: Energy Dependency of filmConcern: Energy Dependency of
film Affects the measured wedge angle in EDW Affects the measured
wedge angle in EDW
profiles for large field size and large depths.profiles for
large field size and large depths.
Elder, et.al, Klein, et.al.Elder, et.al, Klein, et.al.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69 TG69 -- RADIOGRAPHIC FILM FOR RADIOGRAPHIC FILM FOR
MEGAVOLTAGE BEAM DOSIMETRYMEGAVOLTAGE BEAM DOSIMETRY
Stereotactic RadiosurgeryStereotactic RadiosurgeryEnergy
DependencyEnergy Dependency
Overall error of 1%Overall error of 1%-- by using midby using
mid--way calibration for F.S.way calibration for F.S.uptoupto 10x10
cm10x10 cm22 and depths of 2and depths of 2--10cm.10cm.
Output FactorOutput Factor Small field output depends upon the
spatial resolution.Small field output depends upon the spatial
resolution.
Penumbra DelineationPenumbra Delineation Detector size; TG 42
specificationDetector size; TG 42 specification-- detector
dimension of detector dimension of
2mm or less is recommended.2mm or less is recommended.
Concern: Optical ScatterConcern: Optical Scatter Light
transmission artifacts of the scanner contaminating Light
transmission artifacts of the scanner contaminating
the signal (penumbra broadening)the signal (penumbra
broadening)
Dempsey, et.al.,Tsai, et.al.Dempsey, et.al.,Tsai, et.al.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69 TG69 -- RADIOGRAPHIC FILM FOR RADIOGRAPHIC FILM FOR
MEGAVOLTAGE BEAM DOSIMETRYMEGAVOLTAGE BEAM DOSIMETRY
Intensity Modulated Radiation TreatmentIntensity Modulated
Radiation TreatmentFilm dosimetry Film dosimetry -- Best dosimeter
to dateBest dosimeter to date Spatial resolutionSpatial
resolution
Detector size; detector dimension of 2mm or less is Detector
size; detector dimension of 2mm or less is
recommended.recommended.
Concerns: Energy DependencyConcerns: Energy Dependency Varying
component of primary to scatter ratio within the Varying component
of primary to scatter ratio within the
field poses a big problem .field poses a big problem .
Concerns: Spatial Distortion and Optical ScatterConcerns:
Spatial Distortion and Optical Scatter Scanner distortion which are
most apparent in high dose Scanner distortion which are most
apparent in high dose
gradient regions gradient regions throughout IMRT
fieldthroughout IMRT field Optical scatter distorting the
transmitted signalOptical scatter distorting the transmitted
signal
ChuiChui, et. al. Low, et.al., et. al. Low, et.al.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
Kodaks New Kodaks New Extended Dose Range Extended Dose Range
(EDR2) Film(EDR2) Film
Each grain is Each grain is 10 times 10 times smallersmaller
than XV grains,than XV grains,
Uniform cubic grains Uniform cubic grains ofof AgBrAgBr rather
than rather than nonnon--uniform potato uniform potato shaped
grains for XV.shaped grains for XV.
EDR2
XV2
Dose cGyCourtesy: Courtesy: OlchOlch, A., A.
EDR2 vs. XV2EDR2 vs. XV2
-
15
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
No MU reduction is required for EDR2 film No MU reduction is
required for EDR2 film IMRT QA.IMRT QA.
AvoidsAvoids LinacLinac delivery problems with small delivery
problems with small number of MU per segmentnumber of MU per
segment
Avoids round off errors for systems that can not Avoids round
off errors for systems that can not deliver nondeliver non--integer
MUinteger MU
IMRT QA can be performed on the IDENTICAL IMRT QA can be
performed on the IDENTICAL plan that is used to treat the
patient.plan that is used to treat the patient.
EDR2 film is less sensitive to processor EDR2 film is less
sensitive to processor variations than XV2 film.variations than XV2
film.
Courtesy: Courtesy: OlchOlch, A., A.
KODAKS NEW EDR2 FILMKODAKS NEW EDR2 FILM
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
TG69 TG69 -- RADIOGRAPHIC FILM FOR RADIOGRAPHIC FILM FOR
MEGAVOLTAGE BEAM DOSIMETRYMEGAVOLTAGE BEAM DOSIMETRY
TG Chapters:TG Chapters: Introduction and Background
Introduction and Background -------------------------- S. PaiS.
Pai
Characteristics ofCharacteristics of AgHAgH films films
-------------------------- I. DasI. Das
Film types and Processors Film types and Processors
-------------------------- K. LamK. Lam
Detection Equipment Detection Equipment
Point Point Densitometers Densitometers
-------------------------- A. Olch/L. E. ReinsteinA. Olch/L. E.
Reinstein
2D scanners 2D scanners -------------------------- J. Dempsey/J.
WilliamsonJ. Dempsey/J. Williamson
Phantom considerations Phantom considerations andand
-------------------------- E. GreinE. Grein
Film Calibration ProtocolFilm Calibration Protocol
Special ApplicationsSpecial Applications
QA of photon/Electron beams QA of photon/Electron beams
-------------------------- J. J. PaltaPalta
IMRT/EDW/SRS IMRT/EDW/SRS -------------------------- T.
LossasoT. Lossaso
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
ReferencesReferences[1] Attix, F.H. Introduction to Radiological
Physics and Radiation Dosimetry. New York: John
Wiley & Sons; 1986. [2] Avadhani, J.S., Pradhan, A.S.,
Sankar, A. and Viswanathan, P.S. Dosimetric aspects of physical
and dynamic wedge of Clinac 2100C linear accelerator [see
comments]. Strahlenther. Onkol. 173: 524-8, 1997.
[3] Aydarous, A.S., Darley, P.J. and Charles, M.W. A wide
dynamic range, high-spatial-resolution scanning system for
radiochromic dye films. Phys. Med. Biol. 46: 1379-1389, 2001.
[4] Bartlett, D.T. and Creasey, F.L. Latent image fading in
nuclear emulsions. Phys. Med. Biol. 22: 1187-1188, 1977.
[5] Beavis, A.W., Weston, S.J. and Whitton, V.J. Implementation
of the Varian EDW into a commercial RTP system. Phys. Med. Biol.
41: 1691-704, 1996.
[6] Becker, K. Solid State Dosimetry. Boca Raton, Fl: CRC Press;
1973. [7] Bogucki, T.M., Murphy, W.R., Baker, C.W., Piazza, S.S.
and Haus, A.G. Processor quality
control in laser imaging systems. Med. Phys. 24: 581-584, 1997.
[8] Bos, L., Danciu, C., Cheng, C.W., et al. Inter-institutional
variations of sensitometric curves of
radiographic dosimetric films. Med. Phys. 29: (in press), 2002.
[9] Burch, S.E., Kearfott, K.J., Trueblood, J.H., et al. A new
approach to film dosimetry for high
energy photon beams: Lateral scattering filtering. Med. Phys.
24: 775-783, 1997. [10] Butson, M.J., Cheung, T. and Yu, P.K.
Spatial resolution of a stacked radiochromic film
dosimeter. Radiother. Oncol. 61: N27-31, 2001.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[11] Butson, M.J., Cheung, T., Yu, P.K.
and Metcalfe, P.E. Assessment of large single-
fraction, low-energy X-ray dose with radiochromic film. Int. J.
Radiat. Oncol. Biol. Phys. 46: 1071-1075, 2000.
[12] Butson, M.J., Cheung, T. and Yu, P.K.N. Radiochromic film
dosimetry in water phantoms. Phys. Med. Biol. 46: N27-N31,
2001.
[13] Butson, M.J., Mathur, J.N. and Metcalfe, P.E. Radiochromic
film as a radiotherapy surface-dose detector. Phys. Med. Biol. 41:
1073-1078, 1996.
[14] Butson, M.J., Yu, P.K., Cheung, T., et al. Dosimetry of
blood irradiation withradiochromic film. Transfusion Medicine 9:
205-208, 1999.
[15] Butson, M.J., Yu, P.K. and Metcalfe, P.E. Effects of
read-out light sources and ambient light on radiochromic film.
Phys. Med. Biol. 43: 2407-2412, 1998.
[16] Butson, M.J., Yu, P.K. and Metcalfe, P.E. Measurement of
off-axis and peripheral skin dose using radiochromic film. Phys.
Med. Biol. 43: 2647-2650, 1998.
[17] Cadman, P. Use of CEA TVS film for measuring high energy
photon beam dose distributions. Med. Phys. 25: 1435-1437, 1998.
[18] Cheng, C.W. and Das, I.J. Dosimetry of high energy photon
and electron beams with CEA films. Med. Phys. 23: 1225-1231,
1996.
[19] Cheung, T., Butson, M. and Yu, P. Multilayer gafchromic
film detectors for breast skin dose determination in vivo. Phys.
Med. Biol. 47: N31-N37, 2002.
[20] Cheung, T., Butson, M.J. and Yu, P.K. Use of multiple
layers of Gafchromic film to increase sensitivity. Phys. Med. Biol.
46: N235-N240, 2001.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[21] Cook, L.T., Insana, M.F., McFadden,
M.A., Hall, T.J. and Cox, G.G. Comparison of the low-
contrast detectability of a screen-film system and third
generation computed radiography. Med. Phys. 21(5): 691-695,
1994.
[22] Danciu, C., Proimos, B.S., Rosenwald, J.C. and Mijnheer,
B.J. Variation of sensitometric curves of radiographic films in
high energy photon beams. Med. Phys. 28: 966-974, 2001.
[23] Dempsey, J.F., Low, D.A., Kirov, A.S. and Williamson, J.F.
Quantitative optical densitometry with scanning-laser film
digitizers. Med. Phys. 26: 1721-1731, 1999.
[24] Dempsey, J.F., Low, D.A., Mutic, S., et al. Validation of a
precision radiochromic film dosimetry system for quantitative
two-dimensional imaging of acute exposure dose distributions.
Medical Physics 27: 2462-2475, 2000.
[25] Dixon, R.L. and Ekstrand, K. A film dosimetry system for
use in computed tomography. Radiology 127: 255-258, 1978.
[26] Dobson, G.M.B., Griffith, I.O. and Harrison, D.N.
Photographic Photometry. Oxford: The Clarendon Press; 1926.
[27] Duggan, D.M., Coffey, C.W., 2nd, Lobdell, J.L. and Schell,
M.C. Radiochromic film dosimetry of a high dose rate beta source
for intravascular brachytherapy. Med. Phys. 26: 2461-2464,
1999.
[28] Dutreix, J. and Dutreix, A. Film dosimetry of high-energy
electrons. Ann. N Y Acad. Sci 161: 33-43, 1969.
[29] Ehrlich, M. Characteristic curves for X-ray exposures at
various dose rates. J. Opt. Soc. Am. 46: 801-, 1956.
[30] el-Khatib, E., Antolak, J. and Scrimger, J. Evaluation of
film and thermoluminescent dosimetry
of high-energy electron beams in heterogeneous phantoms. Med.
Phys. 19: 317-323, 1992.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[31] Evans, M.D. and Schreiner, L.J. A
simple technique for film dosimetry. Radiother.
Oncol. 23: 265-267, 1992. [32] Foulkes, K., Ostwald, P. and
Kron, T. A clinical comparison of different film systems for
radiotherapy portal imaging. Med. Dosim. 26: 281-284, 2001. [33]
Francescon, P., Cora, S., Cavedon, C., et al. Use of a new type of
radiochromic film, a
new parallel-plate micro-chamber, MOSFETs, and TLC 800
microcubes in the dosimetry of small beams. Med. Phys. 25: 503-511,
1998.
[34] Granke, R.C., Wright, K.A., Evans, W.W., Nelson, J.E. and
Trump, J.G. The film method of tissue dose studies. Am. J.
Roentgenol. 72: 302-307, 1954.
[35] Gurney, R.W. and Mott, N.F. The theory of photolysis of
silver bromide and the photographic latent image. Proc. Roy. Soc.
A164: 151, 1938.
[36] Hale, J.I., Kerr, A.T. and Shragge, P.C. Calibration of
film for accurate megavoltage photon dosimetry. Med. Dosim. 19:
43-46, 1994.
[37] Haus, A.G. Advances in Film Processing Systems Technology
and Quality Control in Medical Imaging. Madison, Wi: Medical
Physics Publishing; 2001.
[38] Haus, A.G., Dickerson, R.E., Huff, K.E., et al. Evaluation
of a cassette-screen-film combination for radiation therapy portal
localization imaging with improved contrast.Med. Phys. 24: 1605-8,
1997.
[39] Haus, A.G., Dickerson, R.E., Huff, K.E., et al. Evaluation
of cassette-screen-film combination for radiation therapy portal
localization imaging with improved contrast.Med. Phys. 24:
1605-1613, 1997.
[40] Herz, R.H. The Photographic Action of Ionizing Radiations.
New York: Wiley-Interscience; 1969.
-
16
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[41] Ju, S.G., Ahn, Y.C., Huh, S.J. and
Yeo, I.J. Film dosimetry for Intensity modulated radiation
therapy: dosimetric evaluation. Med. Phys. 29: 351-355, 2002.
[42] Kellermann, P.O., Ertl, A. and Gornik, E. A new method of
readout in radiochromic film
dosimetry. Phys. Med. Biol. 43: 2251-2263, 1998. [43] Klein,
E.E., Low, D.A., Meigooni, A.S. and Purdy, J.A. Dosimetry and
clinical
implementation of dynamic wedge. Int. J. Radiat. Oncol. Biol.
Phys. 31: 583-92, 1995. [44] Langmack, K.A. and Goss, V.
Characterization of new portal film systems for radiotherapy
verification. Br. J. Radiol. 72: 479-484, 1999. [45] Li, Z.,
Wen, D., Chen, D., et al. A study of dosimetric characteristics of
GAF DM-1260
Radiochromic films. Radiat. Phys. Chem. 57: 103-113, 2000. [46]
Ma, L., Li, X.A. and Yu, C.X. An efficient method of measuring the
4 mm helmet output
factor for the Gamma knife. Phys. Med. Biol. 45: 729-733, 2000.
[47] Mayer, R., Williams, A., Frankel, T., et al. Two-dimensional
film dosimetry application in
heterogeneous materials exposed to megavoltage photon beams.
Med. Phys. 24: 455-460, 1997.
[48] McLaughlin, W.L., Soares, C.G., Sayeg, J.A., et al. The use
of a radiochromic detector for the determination of stereotactic
radiosurgery dose characteristics. Med. Phys. 21: 379-388,
1994.
[49] McLaughlin, W.L., Yun-Dong, C., Soares, C.G., et al.
Sensitometry of the response of a newradiochromic film dosimeter to
gamma radiation and electron beams. Nucl. Instr. Meth. Phys.Res.
A302: 165-176, 1991.
[50] Meigooni, A.S., Sanders, M.F., Ibbott, G.S. and Szeglin,
S.R. Dosimetric characteristics of an improved radiochromic film.
Med. Phys. 23: 1883-1888, 1996.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[51] Meigooni, A.S., Zhu, Y., Williamson,
J.F., et al. Design and dosimetric characteristics of a high
dose rate remotely afterloaded endocavitary applicator system.
Int. J. Radiat. Oncol. Biol. Phys. 34: 1153-1163, 1996.
[52] Menon, G. and Sloboda, R. Measurement of relative output
for 90Sr ophthalmic applicators usingradiochromic film. Med. Dosim.
25: 171-177, 2000.
[53] Muench, P.J., Meigooni, A.S., Nath, R. and McLaughlin, W.L.
Photon energy dependence of the sensitivity of radiochromic film
and comparison with silver halide and LiF TLDs used for
brachytherapy dosimetry. Med. Phys. 18: 767-775, 1991.
[54] Ningnoi, T. and Ehlermann, D.A.E. Effects of temperature
and humidity during irradiation on the response of radiochromic
film dosimeters. Radiat. Phys. Chem. 43: 569-572, 1994.
[55] Niroomand-Rad, A. Comment on "Dosimetric characteristics of
an improved radiochromic film" [Med. Phys. 23, 1883-1888 (1996)]
and on "Qualitative evaluation of radiochromic film response for
two-dimensional dosimetry" [Med. Phys. 24, 223-231 (1997)]. Med.
Phys. 24: 1317, 1997.
[56] Niroomand-Rad, A., Blackwell, C.R., Coursey, B.M., et al.
Radiographic film dosimetry: Recommendations of AAPM Radiation
Therapy Committee Task Group 55. Med. Phys. 25: 2093-2115,
1998.
[57] Niroomand-Rad, A., Gillin, M.T., Kline, R.W. and Grimm,
D.F. Film dosimetry of small electron beams for routine
radiotherapy planning. Med. Phys. 13: 416-21, 1986.
[58] Olch, A. Dosimetric performance of an enhanced dose range
radiographic fFilm for intensity modulated radiation therapy
quality assurance. Med. Phys. 29: (in press), 2002.
[59] Pai, S., Reinstein, L.E., Gluckman, G., Xu, Z. and Weiss,
T. The use of improved radiochromicfilm for in vivo quality
assurance of high dose rate brachytherapy. Med. Phys. 25: 1217-21.,
1998.
[60] Piermattei, A., Miceli, R., Azario, L., et al. Radiochromic
film dosimetry of a low energy proton beam. Med. Phys. 27:
1655-1660, 2000.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[61] Ramani, R., Lightstone, A.W., Mason,
D.L. and O'Brien, P.F. The use of radiochromic film in
treatment verification of dynamic stereotactic radiosurgery.
Med. Phys. 21: 389-392, 1994. [62] Ramani, R., Lightstone, A.W.,
Mason, D.L.D. and O'Brien, P.F. The use of radiochromic film in
treatment verification of dynamic stereotactic radiosurgery.
Med. Phys. 21: 389-392, 1994. [63] Reinstein, L.E. and Gluckman,
G.R. Comparison of dose response of radiochromic film measured
with He-Ne laser, broadband, and filtered light densitometers.
Med. Phys. 24: 1531-1533, 1997. [64] Reinstein, L.E., Gluckman,
G.R. and Amols, H.I. Predicting optical densitometer response as
a
function of light source characteristics for radiochromic film
dosimetry. Med. Phys. 24: 1935-1942, 1997.
[65] Reinstein, L.E., Gluckman, G.R. and Meek, A.G. A rapid
colour stabilization technique forradiochromic film dosimetry.
Phys. Med. Biol. 43: 2703-2708, 1998.
[66] Roback, D.M., Johnson, J.M., Khan, F.M., Engeler, G.P. and
McGuire, W.A. The use of tertiary collimation for spinal
irradiation with extended SSD electron fields. Int. J. Radiat.
Oncol. Biol. Phys. 37: 1187-1192, 1997.
[67] Robar, J.L. and Clark, B.G. The use of radiographic film
for linear accelerator stereotactic radiosurgical dosimetry. Med.
Phys. 26: 2144-2150, 1999.
[68] Roberts, R. Portal imaging with film-cassette combinations:
what film should we use? Br. J.Radiol. 69: 70-71, 1996.
[69] Schumer, W., Fernando, W., Carolan, M., et al. Verification
of brachytherapy dosimetry withradiochromic film. Med. Dosim. 24:
197-203, 1999.
[70] Spielberger, B., Scholz, M., Krmer, M. and Kraft, G.
Experimental investigations of the response of films to heavy-ion
irradiation. Phys. Med. Biol. 46: 2889-2897, 2001.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences[71] Stevens, M., Turner, J., Hugtenburg,
R. and Butler, R. High-resolution dosimetry using
radiochromic film and a document scanner. Phys. Med. Biol. 41:
2357-2365, 1996. [72] Suchowerska, N., Hoban, P., Butson, M.,
Davison, A. and Metcalfe, P. Directional dependence in
film dosimetry: radiographic and radiochromic film. Phys. Med.
Biol. 46: 1391-1397, 2001. [73] Suchowerska, N., Hoban, P.,
Davison, A. and Metcalfe, P. Perturbation of radiotherapy beams
by
radiographic film: measurements and Monte Carlo simulations.
Phys. Med. Biol. 44: 1755-1765, 1999.
[74] van Battum, L.J. and Heijmen, B.J. Film dosimetry in water
in a 23 MV therapeutic photon beam.Radiother. Oncol. 34: 152-159,
1995.
[75] van Battum, L.J. and Huizenga, H. Film dosimetry of
clinical electron beams. Int J Radiat Oncol Biol Phys 18: 69-76,
1990.
[76] van Bree, N.A., Idzes, M.H., Huizenga, H. and Mijnheer,
B.J. Film dosimetry for radiotherapy treatment planning
verification of a 6 MV tangential breast irradiation. Radiother.
Oncol. 31: 251-255, 1994.
[77] Vatnitsky, S.M. Radiochromic film dosimetry for clinical
proton beams. Appl Radiat Isot 48: 643-651, 1997.
[78] Vatnitsky, S.M., Miller, D.W., Moyers, M.F., et al.
Dosimetry techniques for narrow proton beam radiosurgery. Phys.
Med. Biol. 44: 2789-2801, 1999.
[79] Vatnitsky, S.M., Schulte, R.W., Galindo, R., Meinass, H.J.
and Miller, D.W. Radiochromic film dosimetry for verification of
dose distributions delivered with proton-beam radiosurgery.
Phys.Med. Biol. 42: 1887-1898, 1997.
[80] Williamson, J.F., Khan, F.M. and Sharma, S.C. Film
dosimetry of megavoltage photon beams: a practical method of
isodensity-to-isodose curve conversion. Medical Physics 8: 94-98,
1981.
Das/Cheng/Das/Cheng/PaiPai/AAPM//2002/AAPM//2002
--ReferencesReferences
[81] Wu, A. and Krasin, F. Film dosimetry analyses on the effect
of gold shielding for iodine-125 eye plaque therapy for choroidal
melanoma. Med. Phys. 17: 843-846, 1990.
[82] Yasuda, T., Beatty, J., Biggs, P.J. and Gall, K.
Two-dimensional dose distribution of a miniature x-ray device for
stereotactic radiosurgery. Med. Phys. 25: 1212-1216, 1998.
[83] Yeo, I.J., Wang, C.K. and Burch, S.E. A filtration method
for improving film dosimetry in photon radiation therapy. Med.
Phys. 24: 1943-1953, 1997.
[84] Yeo, I.J., Wang, C.K. and Burch, S.E. A new approach to
film dosimetry for high-energy photon beams using organic plastic
scintillators. Phys. Med. Biol. 44: 3055-3069, 1999.
[85] Zhu, R., Jursinic, P., Grimm, D., et al. Evaluation of
Kodak EDR2 film for dose verification of intensity modulated
radiation therapy delivered by a static multileaf collimator. Med.
Phys. 29: (in press), 2002.
[86] Zhu, Y., Kirov, A.S., Mishra, V., Meigooni, A.S. and
Williamson, J.F. Quantitative evaluation of radiochromic film
response for two-dimensional dosimetry. Med. Phys. 24: 223-231,
1997