2017 AAPM Annual Meeting
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Session Title: HDR Brachytherapy: Treatment Verification Methods
Question 1: Which of the following statement best describe the use of in-vivo dosimetry in brachytherapy that has been investigated so far:
Reference:
Choice A:It can be used to track and record the dose received by an organ at each treatment.
Choice B:It can be used to detect errors in dose delivery during treatment, and take corrective actions as needed.
Choice C:It can be used to detect errors in source positioning by the afterloader.
Choice D:All of the above.
Question 2: The sensitivity and specificity of an electromagnetic tracking system for digitization QA has been demonstrated, in phantom, to be:
Reference:Damato et al., Med Phys 41 (10) 2014
Choice A:100% for errors in which the incorrect channel number was assigned to a catheter.
Choice B:100% for all digitization errors > 0.43 mm.
Choice C:Electromagnetic tracking is incompatible with brachytherapy equipment and therefore its use for digitization QA has never been investigated.
Choice D:Higher when used insider an MRI scanner.
Question 3: When CBCT was used in conjunction with TRUS for HDR prostate brachytherapy, it was found that:
Reference:Even et al., Brachytherapy, 13, 128-136, 2014.
Choice A:Registration uncertainties between the two image modalities lead to uncertainties larger than with TRUS alone.
Choice B:Large differences were found between needle tips on TRUS and CBCT.
Choice C:Reducing the TRUS step size from 2.5 to 1 mm improved the accuracy of needle tips identification on TRUS.
Choice D:Increasing the time of the overall procedure to add CBCT is not justified by results.
Question 4: When using CBCT-based 3D planning in HDR brachytherapy for cervical cancer:
Reference:Al-Halabi et al., IJROBP, 77 (4), 1092-1097, 2010.
Choice A:HRCTV (high risk CTV) is easily identifiable.
Choice B:Patient can be imaged in lithonomy position due to the clearance afforded by the CBCT unit.
Choice C:D2cc to OARs (organs at risk) are accurate for all patient sizes.
Choice D:Intracavitary applicators are hard to digitize due to the poor image resolution.
Question 5: Regarding the verification of brachytherapy treatment plans, which of the following is false:
Reference:US Nuclear Regulatory Commission. 10 CFR 35.2, and American College of Radiology. ACR practice guideline for radiation oncology. Philadelphia: American College of Radiology; 2004.
Choice A:It is a legal requirement, and is mandated by the ACR-ASTRO guidelines.
Choice B:AAPM recommendations include independent plan verification.
Choice C:FMEA is an effective QA tool for EBRT only.
Choice D:Automated checking of BT plan and treatment parameters is more effective than manual checks.
Question 6: Which of the following is incorrect with regard to independent dose calculations for plan verification:
Reference:a. see Cohen et al. An independent dose-to-point calculation program for the verification of high-dose-rate brachytherapy treatment planning Int. J. Radiation Oncology Biol. Phys., Vol. 48, No. 4, pp. 1251–1258, 2000 b. see Pujades et al, The use of nomograms in LDR-HDR prostate brachytherapy Journal of Contemporary Bra chy the ra py 2011/volume 3/number 3 c. Marqa et al. A dose verification tool for high-dose-rate interstitial brachytherapy treatment planning in accelerated partial breast irradiation. Brachytherapy 11 (2012) 359e368
Choice A:Independent reconstruction of the treatment plan can effectively predict common errors.
Choice B:Nomogram calculations may be used for secondary calculations.
Choice C:Independent dose calculation can be used to assess plan quality.
Choice D:Independent dose calculation must agree to within 20% of planned doses.
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