Linear Accelerator Daily QA - Weebly

Linear Accelerator Daily QA1,2 Procedure Non-IMRT IMRT SRS/SBRT

Dosimetry

X-ray output constancy (all energies) 3%

Electron output constancy* 3%

Mechanical

Laser localization 2 mm 1.5 mm 1 mm

Optical Distance Indicator (ODI) at isocenter 2 mm 2 mm 2 mm

Collimator size indicator 2 mm 2 mm 1 mm

Safety

Door Interlock Functional

Door closing safety Functional

Audiovisual monitors Functional

Stereotactic interlocks NA NA Functional

Radiation area monitor (if used) Functional

Beam on indicator Functional

*Electron output constancy only needs to be performed weekly except for machines with unique e-monitoring requiring daily checks

Linear Accelerator Monthly QA1,2

Procedure Non-IMRT IMRT SRS/SBRT

Dosimetry

X-ray output constancy

Electron output constancy 2%

Backup monitor chamber constancy

Typical dose rate output constancy NA 2% IMRT dose rate 2% stereo dose rate, MU

Photon beam profile constancy 1%

Electron beam profile constancy 1%

Electron beam energy constancy 2%/2 mm

Mechanical

Light/radiation field coincidence 2 mm or 1% on a side

Light/radiation field coincidence (asymmetric) 1 mm or 1% on a side

Distance check-lasers with front pointer 1 mm

Gantry/Collimator angle indicators* 1.0°

Accessory trays 2 mm

Jaw position indicators (symmetric) 2 mm

Jaw position indicators (asymmetric) 1 mm

Cross-hair centering 1 mm

Treatment couch position indicators 2 mm/1° 2 mm/1° 1 mm/0.5°

Wedge placement accuracy 2 mm

Compensator placement accuracy 1 mm

Latching of wedges, blocking tray Functional

Localizing lasers ± 2 mm ± 1 mm ˂ ± 1 mm

Safety

Laser guard-interlock test Functional

Respiratory Gating

Beam output constancy 2%

Phase, amplitude beam control Functional

In-room respiratory monitor system Functional

Gating interlock Functional

*at cardinal angles

Linear Accelerator Annual QA1,2

Procedure Non-IMRT IMRT SRS/SBRT

Dosimetry

X-ray flatness change from baseline 1%

X-ray symmetry change from baseline ±1%

Electron flatness change from baseline 1%

Electron symmetry change from baseline ±1%

SRS arc rotation mode - 0.5-10 MU/deg NA NA

MU vs delivered: 1.0 MU or 2% (whichever is

greater) Gantry arc set vs

delivered: 1.0° or 2% (whichever is greater)

X-ray/electron output calibration (TG-51) ±1% (Absolute)

Spot check of field size dependent output factors for x-ray (2 or more)

2% for FS˂4 x 4cm2

1% for FS≥ 4 x 4cm2

Output factors for electron applicators (spot check for one applicator/energy)

±2% from baseline

X-ray beam quality (PDD10 or TMR2010) ±1% from baseline

Electron beam quality (R50) ±1 mm

Physical wedge transmission factor constancy

±2%

X-ray monitor unit linearity (output constancy)

2%≥ 5MU ±5% (2-4 MU)

±2% ≥ 5 MU ±5% (2-4 MU)

±2% ≥ 5 MU

Electron monitor unit linearity (output constancy)

±2%≥ 5 MU

X-ray output constancy vs dose rate ±2% from baseline

X-ray output constancy vs gantry angle ±1% from baseline

Electron output constancy vs gantry angle

±1% from baseline

Electron and x-ray off-axis factor constancy vs gantry angle

±1% from baseline

Arc mode (expected MU, degrees) ±1% from baseline

TBI/TSET Mode Functional

PDD or TMR and OAF constancy 1% (TBI) or 1 mm PDD shift (TSET)

from baseline

TBI/TSET output calibration 2% from baseline

TBI/TSET accessories 2% from baseline

Mechanical

Collimator rotation isocenter ±1 mm from

baseline

Gantry rotation isocenter ±1 mm from

baseline

Couch rotation isocenter ±1 mm from

baseline

Electron applicator interlocks Functional

Coincidence of radiation and mechanical isocenter

±2 mm from baseline



Table top sag 2 mm from baseline

Table angle 1°

Table travel maximum range in movement - all directions

±2 mm

Stereotactic accessories, lockouts, etc. NA NA Functional

Safety

Follow manufacturer's test procedures Functional

Respiratory Gating

Beam energy constancy 2%

Temporal accuracy of phase/amplitude gate on

100 ms of expected

Calibration of surrogate for respiratory phase/amplitude

100 ms of expected

Interlock testing Functional

Imaging Daily QA1 Procedure Non-SRS/SBRT SRS/SBRT

Planar kV and MV (EPID) Imaging

Collison interlocks Functional Functional

Positioning/repositioning ≤ 2 mm ≤ 1 mm

Imaging and treatment coordinate coincidence (single gantry angle) ≤ 2 mm ≤ 1 mm

Cone-beam CT (kV and MV)

Collison interlocks Functional Functional

Positioning, repositioning ≤ 1 mm ≤ 1 mm

Imaging and treatment coordinate coincidence ≤ 2 mm ≤ 1 mm

Imaging Monthly QA1 Procedure Non-SRS/SBRT SRS/SBRT

Planar MV Imaging (EPID) Imaging and treatment coordinate coincidence (four cardinal angles)

≤ 2 mm ≤ 1 mm

Scaling ≤ 2 mm ≤ 2 mm

Spatial resolution Baseline Baseline

Contrast Baseline Baseline

Uniformity and noise Baseline Baseline

Planar kV Imaging Imaging and treatment coordinate coincidence (four cardinal angles)

≤ 2 mm ≤ 1 mm

Scaling ≤ 2 mm ≤ 1 mm




Cone-beam CT (kV and MV) Geometric distortion ≤ 2 mm ≤ 1 mm



HU constancy Baseline Baseline


Imaging Annual QA1 Procedure Non-SRS/SBRT SRS/SBRT

Planar MV imaging (EPID) Full range of travel SDD ±5 mm ±5 mm

Imaging dose Baseline Baseline

Planar kV imaging Beam quality/energy Baseline Baseline

Imaging dose Baseline Baseline

Cone-beam CT (kV and MV) Imaging dose Baseline Baseline

Radiographic Simulator Daily QA2 Procedure Tolerance

Localizing lasers 2 mm

Optical Distance Indicator (ODI) 2 mm

Radiographic Simulator Monthly QA2 Procedure Tolerance

Field size indicator 2 mm

Gantry/collimator angle indicators 1°

Cross-hair centering 2 mm diameter

Focal spot-axis indicator 2 mm

Fluoroscopic image quality Baseline

Emergency/collision avoidance Functional

Light/radiation field coincidence 2 mm or 1%

Film processor sensitometry Baseline

Radiographic Simulator Annual QA2 Procedure Tolerance

Mechanical Checks Collimator rotation isocenter 2 mm diameter

Gantry rotation isocenter 2 mm diameter

Couch rotation isocenter 2 mm diameter

Coincidence of collimator, gantry, couch axes, and isocenter

2 mm diameter

Tabletop sag 2 mm

Vertical travel of couch 2 mm

Radiographic Checks Exposure rate Baseline

Tabletop exposure with fluoroscopy Baseline

kVp and mAs calibration Baseline

High- and low-contrast resolution Baseline

CT Simulator Daily QA2,3 Procedure Test Objective Tolerance

Electromechanical Alignment of gantry lasers with the center of imaging plane

Verify proper identification of scan plane with gantry lasers

±2 mm

Image Performance CT number accuracy CT number for water 0±5 HU

Image Noise Manufacturer specifications

In plane spatial integrity x or y direction ±1 mm

CT Simulator Monthly QA2,3 Procedure Test Objective Tolerance

Electromechanical

Orientation of gantry lasers with the respect to imaging plane*

Verify gantry lasers are parallel & orthogonal with the imaging plane

over the full length of laser projection

±2 mm over length of laser projection

Spacing of lateral wall lasers with respect to lateral gantry lasers and scan plane*

Verify lateral wall lasers are accurately spaced from the scan

plane ±2 mm

Orientation of wall lasers with respect to the imaging plane*

Verify wall lasers are parallel & orthogonal with the imaging plane

over the full length of laser projection


Orientation of ceiling lasers with respect to the imaging plane*

Verify ceiling laser is orthogonal with the imaging plane


Orientation of CT-scanner tabletop with respect to imaging plane**

Verify CT-scanner tabletop is level & orthogonal with imaging plane

±2 mm over length and width of tabletop

Table vertical and longitudinal motion Verify table longitudinal motion according to digital indicators is

accurate & reproducible

±1 mm over the range of table motion

Image Performance CT number accuracy 4-5 different materials For water, 0±5 HU

In plane spatial integrity In both x & y directions ±1 mm

Field uniformity Most commonly used kVp within ±5 HU

* Monthly and after laser adjustments **Monthly or when daily laser QA tests reveal rotational problems

CT Simulator Semi-Annual QA2,3 Procedure Test Objective Tolerance

Electromechanical

Sensitivity profile width Verify the sensitivity profile width meets manufacturer specification

±1 mm of nominal value

CT Simulator Annual QA2,3 Procedure Test Objective Tolerance

Electromechanical

Table indexing and position Verify table indexing and position

accuracy under scanner control ±1 mm over scan range

Gantry tilt accuracy Verify accuracy of gantry tilt

indicators ±1° over gantry tilt range

Gantry tilt position accuracy Verify gantry accurately returns to

nominal position after tilting ±1° or ±1 mm from nominal

position

Scan localization Verify accuracy of scan localization

form pilot images ±1 mm over scan range

Radiation profile width Verify radiation profile width meets

manufacturer specification Manufacturer specifications

Image Performance CT number accuracy Electron density phantom For water, 0±5 HU

Field uniformity Other used kVp settings within ±5 HU

Electron density to CT number conversion Annually or after scanner calibration

Consistent with commissioning results & test

phantom manufacturer specifications

Spatial resolution Manufacturer specifications

Contrast resolution Manufacturer specifications

CT Simulator Other QA Parameters2,3

Procedure Test Objective Tolerance

Electromechanical

Generator tests (After replacement of major generator component)

Verify proper operation of x-ray generator

Manufacturer specifications or Report No. 39

recommendations

QA of Instruments4 Procedure Recommendations Frequency

General QA

Acceptance testing Ensure device is meeting manufacturer's

specifications Upon purchase

Commissioning Setup process for use and measurements;

proper training Prior to departmental

use

Inspection Inspection for wear and tear of equipment At time of use

Equipment QA intercomparisons Particularly for electronic devices Frequently

Comparison of QA results Global comparison of QA results for trends Periodically

Secondary check Measurement should be made using different

device for confirmation

When a large discrepancy is seen

during QA

Ionization Chambers & Electrometers Accredited Dosimetry Calibration Laboratory (ADCL) calibration

Act as the primary standard Calibrated every 2

years

Secondary ion chamber/electrometer Intercompared with the primary standard

Minimum of twice per year/ Before or after

any instrument is sent to ADCL for calibration

Beam Scanning Systems On-site acceptance testing, commissioning, & training

Ensure device is meeting manufacturer's specifications

Upon purchase

Functionality of scanning detectors, accuracy and reproducibility of moving in x,y,z directions, and functionality of software

Prior to use/ after software upgrade

Physics Instruments

Ruler (at least one) Calibrated traceable to the National Institute of

Standards and Technology (NIST)

Thermometer/Barometer Should have at least 2 of each device with one

set aside as reference, NIST traceable Upon purchase and at

least semi-annually

Barometer Intercomparisons to nearest weather station Whenever possible

Absolute & Relative Dose Measuring Equipment

Diode and MOSFET QA Monthly

TLD system QA Dependent on

frequency used

Film (radiographic of GaFChromic) QA Dependent on

frequency used

Survey Meters Calibration NRC, Agreement state or state requirement Yearly

Battery check Daily

Constancy check Use low activity radioactive check source to

verify proper operation Daily

MLC QA2 Procedure Tolerance

Patient Specific

Check of MLC-generated field vs. simulator film (or DRR) before each field treated

2 mm

Double check of MLC field by therapists for each fraction Expected field

On-line imaging verification for patient on each infraction Physician discretion

Port film approval before second fraction Physician discretion

Quarterly

Setting vs. light field vs. radiation field for two designated patterns 1 mm

Testing of network system Expected fields over network

Check of interlocks All must be operational

Annually Setting vs. light vs. radiation field for patterns over range of gantry and collimator angles

1 mm

Water scan of set patterns 50% radiation edge within 1 mm

Film scans to evaluate interleaf leakage and abutted leaf transmission Interleaf leakage <3%, abutted leakage

<25%

Review of procedures and in-service with therapists All operators must fully understand

operation and procedures

Dynamic/Universal/Virtual Wedges QA1

Procedure Dynamic

Tolerance Universal Tolerance

Virtual Tolerance

Daily

Morning check-out run for one angle Functional

Monthly

Wedge factor for all energies C.A. axis 45°or 60°

WF (within 2%) C.A. axis 45°or 60°

WF (within 2%) 5% from unity, otherwise 2%

Annual

Check of wedge angle for 60°, full field and spot check for intermediate angle, field size

Check of off-center ratios @ 80% field

width @ 10 cm to be within 2%

Acceptance Testing for TPS5 Topic Procedure

CT input Create an anatomical description based on a standard set of CT

scans provided by the vendor, in the format which will be employed by the user

Anatomical description Create a patient model based on the standard CT data discussed

above. Contour the external surface, internal anatomy, etc. Create 3D objects and display.

Beam description Verify that all beam technique functions work, using a standard

beam description provided by the vendor.

Photon beam dose calculations

Perform dose calculations for a standard photon beam dataset. Tests should include various open fields, different SSDs, blocked fields, MLC-shaped fields, inhomogeneity test cases, multi-beam

plans, asymmetric jaw fields, wedged fields, and others.

Electron beam dose calculations Perform dose calculations for a standard electron beam dataset. Include open fields, different SSDs, shaped fields, inhomogeneity

test cases, surface irregularity, test cases, and others.

Brachytherapy dose calculations

Perform dose calculations for single sources of each type, as well as several multi-source implant calculations, including standard

implant techniques such as a GYN insertion with tandem and ovoids, two-plane breast implant, etc.

Dose display, dose volume histograms

Display dose calculation results. Use a standard dose distribution provided by the vendor to verify that the DVH code words as

described. User-created dose distributions may also be used for additional tests.

Hardcopy output Print out all hardcopy documentation for a given series of plans and confirm that all textual and graphical information is output

correctly.

Treatment Planning System QA5 Procedure Recommendations

Daily QA

Error Log Review any error messages or hardware malfunctions and keep

log of changes

Change Log Keep log of hardware/software changes

Weekly Digitizer Review digitizer accuracy

Hardcopy output Review all hardcopy output, including scaling for plotter and

other graphics-type output

Computer files Verify integrity of all RTP system data files and executables using checksums or other simple software checks. Checking

software should be provided by vendor.

Review clinical planning Review clinical treatment planning activity. Discuss errors,

problems, complications, difficulties. Resolve problems.

Monthly

CT data input into RTP systems Review the CT data within the planning system for geometrical accuracy, CT number consistency and derived electron density

Problem review Review all RTP problems (for RTP system and clinical planning)

and prioritize problems to be resolved

Review of RTP systems Review current configuration and status of all RTP system

software, hardware, and data files

Annual

Dose calculations Annual checks. Review acceptability of agreement between

measured and calculated doses for each beam/source

Data and I/O devices Review functioning and accuracy of digitizer tablet, video/laser

digitizer, CT input, MR input, printers, plotters, and other imaging output devices

Critical software tools Review BEV/DRR generation and plot accuracy, CT geometry,

density conversions, DVH calculations, other critical tools, machine-specific conversions, data files, and other critical data

Variable

Beam parameterization Checks and/or recommissioning may be required due to

machine changes or problems

Software changes, including operating system Checks and/or recommissioning may be required due to

changes in the RTP software, any support/additional software such as image transfer software, or the operating systems

IMRT QA6 Topic Procedure

Radiation Safety

• Common to have 3-4x the number of MU for IMRT compare to conventional treatment • Primary barrier not a concern • Secondary barrier required to handle leakage radiation especially above 10 MV

Treatment Planning

• Commissioned for IMRT by verifying that the dose predicted by the planning system is accurate within acceptable limits • Geometric test patterns with predictable or known dose are performed

Machine Characteristics • MLC • Dose delivery

Patient-Specific Dose Verification • Must irradiate phantom to verify that the dose delivered is the dose planned

• Can be verified by:

o Point dose measurements for single field (film, ion chamber,

diodes)

o Point dose measurements for all fields (composite film, ion

chamber)

o Planar dose measurements for a single field (specified depth in

phantom, using array of diodes or film) o Planar dose measurements for multiple fields (film)

SRS QA6 Machine Type Guidelines

Linear Accelerator AAPM Report 54 'Stereotactic Radiosurgery'

Gamma Knife AAPM Report 54 "Stereotactic Radiosurgery" and AAPM Task Group 178 'Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance'

CyberKnife AAPM Report 135 'QA for robotic radiosurgery'

Brachytherapy- Sources QA7

Procedure Frequency Tolerance

Long half-life - Description

Physical/Chemical form Initial Purchase Documented

Source encapsulation Initial Purchase Documented

Radionuclide distribution and source uniformity

Initial Purchase Documented

Location of radionuclide Initial Purchase 1 mm

Long half-life - Calibration

Mean of batch Initial Purchase 3%

Deviation from mean Initial Purchase 5%, Documented

Calibration verification Every use

Visual check of source color code

or measurement in calibrator

Short half-life - Description

Physical/Chemical form Initial Purchase Documented

Source encapsulation Initial Purchase Documented

Short half-life - Calibration

Mean of batch Every use 3%

Deviation from mean Every use 5%

Radionuclide distribution and source uniformity

Every use Visual check,

autoradiograph, ionometric check

Brachytherapy - Intracavitary Source and Applicator QA7

Procedure End Point Frequency

Evaluate dimensions/serial number Source identity, physical length and diameter Initially

Superposition of auto-and transmission radiographs

Active source length and uniformity, capsule thickness, accuracy of source construction

Initially

Source leak test Capsule integrity At 6-month

intervals (NRC requirement)

Source calibration Source strength Initially, Annually

Dosimetric evaluation of applicator Magnitude and geometric characteristics of

shielding effect Initially

Orthogonal radiographs of applicators Correct source position, mechanical integrity,

internal shield positioning, coincidence of dummy and radioactive source

Initially, Annually

Measure applicator dimensions Correct diameter and length, correct diameter

of all colpostat caps and cylinder segments Initially, Annually

Source inventory Correct source number Quarterly

Source preparation area survey Safety of brachytherapy personnel As needed

Brachytherapy - Interstitial Source and Applicator QA7

Procedure End Point Frequency

Evaluate spacing and no. seeds/ribbons Ribbon geometry and seed quantity Initially

Source calibration Source strength Initially, Each use

Strength peer seed or strength per unit length

Source strength uniformity Initially

Applicator integrity Metal needles (sharpness and straightness)

Templates (o-ring integrity and hole locations) Initially, Annually

Evaluate dummy ribbon geometry Coincidence of dummy and radioactive

sources Initially, Annually

Source leak test Capsule integrity At 6-month

intervals (NRC requirement)

Source inventory Correct source number Quarterly

Source preparation area survey Safety of brachytherapy personnel As needed

Brachytherapy - Daily QA for Remote Afterloading7

Test Endpoint Test Methodology System Type

Dose delivery accuracy

Verify date, time and source strength in treatment unit and planning computer

All

Verify source strength and timer accuracy against a tertiary standard HDR/PDR

Overall system function

Run system through a complete cycle of simulated treatment:

All

• programming;

• source ejection;

• source retraction at end of timer countdown

Verify treatment status indicator lights and critical source control functions

Correct function of dedicated fluoroscopy/imaging system if present

HDR

Patient/public/staff safety Correct function:

• door interlock; HDR/PDR

• area radiation monitor; HDR/PDR

• audio/visual system communication; HDR/PDR

• portable survey meter; All

• audible/visual error and alarm condition indicators; All

Safety equipment available:

All

• emergency instructions;

• emergency equipment (forceps, emergency safe, surgical supplies);

• operator’s manual;

• survey meter

Measure hourly/weekly radiation levels after patient loaded and portable shields positioned

PDR/LDR

Verify positional accuracy within 1 mm Many possible tests:

All

• primary positional accuracy test for a single catheter;

• deviation of ion chamber response placed near a programmed dwell position;

• multiple-channel autoradiograph of every active dwell position used in the patient treatment and compare programmed position to expected;

• visually check that relative position of source tip in a ruled catheter reproduces from day-to-day

Autoradiograph patient-specific configuration of sources loaded into intermediate safe of device

All fixed and programmable

source-train units

Temporal accuracy Many possible tests:

HDR/PDR

• time duration of ‘‘source ejected’’ light;

• perform a spot check of radiation output for a timed interval using tertiary calibration standard jig;

• compare source arrival and departure times on printed treatment documentation with a clock or stop watch;

• for LDR, subtract treatment interruptions from overall treatment time and compare to programmed time LDR (optional)

Brachytherapy - Quarterly QA for Remote Afterloading7

General Endpoint Tests/Endpoints System Type

Personnel safety Head/machine survey with source retracted All

Patient safety

Important interlocks and emergency response systems function: obstructed applicator, missing applicator, door, unlocked indexer ring, displacement, power/ air pressure loss, backup battery system All

Emergency source handling tools, shielded storage container, and supplies for emergency applicator removal available and functioning All

Calibration of optical and pneumatic source position/status detection systems; any other preventive maintenance or inspections

As specified by vendor

All

Correct operation of all applicators, transfer tubes, and source localization dummies

Examine all dummies for kinks or bends that may shorten their axial displacement through applicator assembly. Check integrity of all transfer tube-applicator interfaces All

Positional accuracy: single stepping source

Verify that radioactive source position agrees with dummy marker within 0.5 mm previously tested against dwell position markers used in simulation.

All HDR/PDR single-stepping source devices

Confirm check cable operation

Obtain multiple channel autoradiograph with unique dwell sequence in each channel: verify that dwell position spacing, assignment of dwell sequence to programmed channel, and relative indexer length to dwell 1 are correct within 1 mm

Confirm accuracy of daily positional test protocol

Transfer tube length (if stability through time is not confirmed and positional accuracy is influenced by tube length)

Positional accuracy: multiple-source machines

Device positions source train in specified treatment location All

Source trains delivered to programmed channels within 1 mm of intended location All

Source trains correctly sorted and composed Programmable

source train

Source inventory correct All

Source trains stored in correct locations in user accessible storage location

Fixed source-train devices

Source calibration Measure source air kerma strength using a ‘secondary’ standard as described in Sec. III HDR/PDR

Redundant source calibration checks

Difference between measured and vendor-specified air kerma strength is within expected margin

HDR/PDR

Use tertiary source strength standard (e.g., daily/monthly output checking system) to confirm primary calibration within 5%. Different electrometer and detector to be used

Various techniques available (Williamson, 1991 and 1994) Spot check of absolute timer accuracy All LDR

Timer accuracy and linearity measurement HDR/PDR

Miscellaneous

Update source strength in treatment planning computer initialization file, treatment unit and quarterly inventory All

Have a second physicist independently review the quarterly report HDR/PDR

Brachytherapy - Annual QA for Remote Afterloading7

Test Endpoint Test Methodology System Type

Personnel and public safety Review workload and annualized unrestricted area/personnel exposures All

Perform facility survey if occupancy/building structure revised All

Dose delivery accuracy

Intercompare secondary standard used for quarterly calibration against another departmental substandard. Obtain new calibration from ADCL if calibration more than two years old

HDR/PDR

Verify air kerma strength calibration and other annual Table I checks LDR

Positional accuracy

Verify accuracy of any jigs or autoradiography cassettes used for daily/monthly positional accuracy verification All

Verify construction/spacing of all simulation markers (dummy sources) All

Verify position of simulation markers agrees with radioactive source for all applicator types. Verify simulation source localization procedure All

Apply Table I/II tests to all intracavitary/interstitial applicators All

If positional accuracy assumes fixed transfer tube length, verify length/uniformity if not checked quarterly All

Temporal accuracy Verify timer linearity and absolute accuracy All

Verify transit dose/source velocity All

Verify pulse sequencing PDR

Additional interlock/emergency response tests

Verify that unit detects simulated detached source capsule HDR/PDR

Verify emergency retraction buttons in room and manual source retraction crank function HDR/PDR

Verify that source retracts and emergency retraction motor activates when excessive friction/applicator obstruction encountered by source All

Miscellaneous

Check that treatment unit correctly decays source strengths and corrects dwell times for decay All

Review accuracy of all standard treatment configurations stored in treatment unit All

Review quality assurance manual and update if necessary. All

Review compliance with personnel training requirements. All

Brachytherapy - QA Computer Planning System7

Function Benchmark Data Frequency Verify geometric accuracy of I/O peripherals; digitizer, CT or ultrasound interface and plotter

Digitize/plot pattern of known geometry; for CT/US, image and reconstruct phantom implant Monthly

Verify input parameters for all precalculated single-source arrays

Published recommendations, source vendor's mechanical drawings, initially, annually Monthly

Verify dose, dwell time, and treatment time calculations at representative points for all source files

Published dose rate tables, manual calculations

Initially, annually, new software

version or source identity

Accuracy of single-source isodoses Point source output

Initially, new software version

Accuracy of multi-source isodose contouring Point source data for symmetric source arrays Initially, new

software version

Accuracy of plan rotation matrix

Constancy of point doses, source positions, and isodoses under repeated orthogonal rotations for symmetric source arrays


Consistency of printed plan documentation Assumed input parameters Every clinical use

Accuracy of coordinate reconstruction Radiograph phantom with known catheter geometry


Accuracy of electronic downloading of treatment parameters of afterloader

Comparison of treatment unit and planning system printed output

Initially, new software version, each treatment

Dose volume histogram/implant figures of merit

Use isotropic point source or segment of line source allowing analytic calculations of DVH


Constancy of test case DVH Annually

Optimization software

Run series of test cases based upon idealized implant geometries of various sizes; develop a sense of what optimization does to an implant compared to uniform loading before trying it on patients

Initially, spot check when software

changes by duplicating old

cases

Overall system check Run series of standardized plans to globally test all clinically used features

Initially, new software version,

annually

References

1. Klein EE, Hanley J, Bayouth J. Task Group 142 report: Quality assurance of medical accelerators. Med

Phys. 2009;36(9):4197-4212. http://doi.org/10.1118/1.3190392.

2. Khan FM. Gibbons JP. The Physics of Radiation Therapy. 5th ed. Philadelphia, PA: Lippincott,

Williams, & Wilkins; 2014.

3. Mutic S, Palta JR, Butker EK, et al. Quality assurance for computed-tomography simulators and the

computed-tomography-simulation process: Report of the AAPM Radiation Therapy Committee Task

Group No. 66. Med Phy. 2003; 30(10):2762-2792. http://doi.org/10.1118/1.1609271.

4. Thomason C, Lenards N. QA of Instruments. [SoftChalk]. La Crosse, WI: UW-L Medical Dosimetry

Program; 2018.

5. Fraass B, Doppke K, Hunt Margie, et al. AAPM radiation therapy committee Task Group 53: Quality

assurance for clinical radiotherapy treatment planning. Med Phys. 1998:25(10):1773-1828.

https://doi.org/10.1118/1.598373.

6. Vann AM, Lenards N. Quality Assurance: QA of TPS, IMRT, SRS. [SoftChalk]. La Crosse, WI: UW-L

Medical Dosimetry Program; 2018.

7. Nath R, Anderson L, Meli J, et al. Code of practice for brachytherapy physics: Report of the AAPM

Radiation Therapy Committee Task Group No. 56. Med. Phys. 1997; 24(10): 1557-1598.

http://dx.doi.org/10.1118/1.597966.

Linear Accelerator Daily QA - Weebly

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