2016 AAPM Annual Meeting
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Session Title: How to Identify and Resolve Potential Clinical Errors Before They Impact Patients Treatment: Lessons Learned
Question 1: Monthly routine calibration of machine using a solid water phantom, there was no problem with photon beam, but a consistent difference of over 3% was noted in electron beam. What could be the problem?
Reference:Reference: Wrong slab was used that has uniform whole proving air gap around chamber. A possible ref: Ho A, Paliwal BR. Stopping-power and mass energy -absorption coefficient ratios for solid water. Med Phys 1986;13:403-404
Choice A:Temperature and pressure correction
Choice B:Change in SSD
Choice C:Changes in flatness & symmetry
Choice D:Wrong phantom slab for ion chamber
Choice E:Defective ion chamber
Question 2: A patient with a centrally located glioblastoma is planned with non-coplanar vertex field. What should be considered for such a field?
Reference:Consider beam path passing through entire body thus giving significant dose to whole body: Das et al, Int J Radiat Oncol Biol Phys 1997;37:1023-1029.
Choice A:PTV coverage
Choice B:Estimation and proper evaluation of DVH
Choice C:Beam angle selection
Choice D:Age of patient
Choice E:Use of MLC
Question 3: After implementation of an in-house online event recording system at the UCSD Cancer Center, were most linac issues resolve by clinic staff, clinic staff with remote assistance, or on-site by a vendor engineer?
Reference:Improving linear accelerator service response with a real-time electronic event reporting system. Hoisak JD, Pawlicki T, Kim GY, Fletcher R, Moore KL. J Appl Clin Med Phys. 2014 Sep 8;15(5):4807. doi: 10.1120/jacmp.v15i5.4807.
Choice A:Clinic staff
Choice B:Clinic staff with remote assistance
Choice C:On-site vendor engineer
Choice D:Comparable frequencies for each of the above
Choice E:None of above
Question 4: Which of the following was not cited as an advantage of an online help desk system for linac problems at the Illawarra Cancer Care Centre?
Reference:Experience with an online helpdesk for equipment fault reporting in a radiation oncology department. McNamara J, Williams M, Carolan M. J Appl Clin Med Phys. 2013 Nov 4;14(6):4396. doi: 10.1120/jacmp.v14i6.4396
Choice A:Eliminates the need for communication between the radiation therapists, physicists, and engineers.
Choice B:Allows access by multiple users simultaneously from any computer in the cancer center, which is an improvement over a fault logbook located at the linac.
Choice C:Observations such as smells and noises in the linac bunker that previously may have been discussed but were never written down are now documented.
Choice D:Field service reports (FSRs) are received in electronic format and can be input into the system immediately.
Choice E:All of above
Question 5: Based on the TLD measured dose in the IROC Houston lung phantoms which of the following heterogeneity correction algorithms calculate a dose that has the closest agreement with the measured dose?
Reference:Kry SF, Alvarez P, Molineu A, Amador C, Galvin J, Followill DS. Algorithms Used in Heterogeneous Dose Calculations Show Systematic Differences as Measured With the Radiological Physics Center's Anthropomorphic Thorax Phantom Used for RTOG Credentialing. Int J Radiat Oncol Biol Phys 85(1):e95-e100, 1/2013.
Choice A:AAA
Choice B:Monte Carlo
Choice C:Convolution superposition
Choice D:Pencil beam
Choice E:Clarkson
Question 6: Depending on the dosimeter used, the magnitude of the additional small field fluence correction, down to a 0.5 x 0.5 cm2 field size can be as much as:
Reference:Francescon et al. Med Phys, Vol. 38, No. 12, December 2011.
Choice A:0%
Choice B:2%
Choice C:5%
Choice D:8%
Choice E:13%
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