2016 AAPM Annual Meeting
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Session Title: New Task Groups for External Beam QA: An Overview
Question 1: Action limits for patient-specific IMRT QA..
Reference:T. Pawlicki, S. Yoo, L.E. Court, et al, "Process control analysis of IMRT QA: implications for clinical trials," PMB 53, 5193-5205 (2008).
Choice A:Identify the boundaries within which the IMRT QA process is considered to be operating normally.
Choice B:Specify the process to detect gross errors in IMRT delivery.
Choice C:Define the amount that quality measures are allowed to deviate without risking harm to the patient as well as defining limit values for when clinical action is required.
Choice D:Minimize the reliance on the concept that all potential sources of error in the IMRT process are known and controlled.
Choice E:Detect treatment data transfer errors.
Question 2: The ASTRO white report, “Safety Considerations for IMRT,” by Moran et al (2011) stated that pre-treatment QA checks should include
Reference:Moran et al, “Safety Considerations for IMRT,” PRO (2011)
Choice A:Creation/calculation of the approved treatment plan for the QA geometry using the dose per fraction specified for patient delivery.
Choice B:Verifying the integrity of the information transferred to the treatment management system.
Choice C:Verifying the correctness of MLC leaf positions, sequences, and fractional monitor units.
Choice D:Verifying the accuracy of monitor units used for the patient dose calculation.
Choice E:All the above
Question 3: What is the IRIS collimator field size repeatability?
Reference:REF: G.G. Echner, W. Kilby, M. Lee, E. Earnst, S. Sayeh, A. Schlaefer, B. Rhein, J.R. Dooley, C. Lang, O. Blanck, E. Lessard, C.R. Maurer, W. Schlegel, "The design, physical properties and clinical utility of an iris collimator for robotic radiosurgery," Phys Med Biol 54, 5359-5380 (2009).
Choice A:0.1 mm
Choice B:0.2 mm
Choice C:0.5 mm
Choice D:0.8 mm
Choice E:1.0 mm
Question 4: When MC is used for spine lesions, how big is the reported difference to a raytracing algorithm?
Reference:E.E. Wilcox, G.M. Daskalov, H. Lincoln, "Stereotactic radiosurgery-radiotherapy: Should Monte Carlo treatment planning be used for all sites?," Practical radiation oncology 1, 251-260 (2011).
Choice A:<3%
Choice B:<5%
Choice C:<10%
Choice D:<15%
Choice E:<20%
Question 5: How should a medical physicist attempt to apply the principles of AAPM Task Group 51 Absorbed Dose to Water to external beam teletherapy sources such as Gamma Stereotactic Radiosurgery devices, Cyberknife, Viewray or Tomotherapy, which do not conform to the geometry described in this report?
Reference:R. Alfonso, P. Andreo, R. Capote et al “A new formalism for reference dosimetry of small and nonstandard fields” Med. Phys. Letter, (35) 11, 5179-5186, Nov. 2008
Choice A:Make a good faith effort, using standard radiological principles to adapt the TG 51 report to your device.
Choice B:Use the formalism outlined by Alfonso et al in Medical Physics.
Choice C:Consult PUBMED for advice from other medical physicists.
Choice D:Use a high level Monte Carlo simulation program to model the problem.
Question 6: What problems prevent users of Gamma Stereotactic Radiosurgery devices from utilizing AAPM Task Group 51 for absorbed dose calibration?
Reference:R.E. Drzymala, P.E. Alvarez, G. Bednarz et al “A round-robin gamma stereotactic radiosurgery dosimetry interinstitution comparison of calibration protocols” Med. Phys., (42) 11, 6745-6756, Nov. 2015
Choice A:Exceedingly small field sizes (down to 4mm).
Choice B:Not enough experience w GSR devices.
Choice C:No appropriate ionization chambers.
Choice D:Nonstandard geometry and impossible to create spherical liquid water phantom.
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