2016 AAPM Annual Meeting
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Session Title: Microdosimeters for Therapy
Question 1: The definition of a small field:
Reference:Das IJ, Ding GX, Ahnesjö A. Small fields: Non-equilibrium radiation dosimetry. Med Phys 2008; 35:206-215
Choice A:Is any field smaller than 3x3 cm2.
Choice B:Is a field that is comparable to focal spot of the machine.
Choice C:Is a field that is smaller than detector.
Choice D:Depends on beam energy due to lateral range of secondary electron.
Choice E:Is when the ratio of the detector reading is equal to ratio of dose.
Question 2: A microdetector is defined as:
Reference:Das IJ et al, TG-106 Med Phys 2008; 35:4186-4215.
Choice A:Any solid state detector.
Choice B:Diode detectors as their size is small.
Choice C:Small volume ion chambers.
Choice D:Diamond detectors.
Choice E:Detectors with sensitive volumes on the order of microns.
Question 3: Dosimetry of small field should be preferably performed with:
Reference:Azangwe et al, Med Phys 41, 072103 (2014); Benmakhlouf et al, Med Phys 41, 041711 (2014)
Choice A:Any micro-detector.
Choice B:Water-equivalent micro-detectors.
Choice C:An Edge detector.
Choice D:A Pinpoint detector.
Choice E:MicroMosfets.
Question 4: Microdetectors are well suited for small field dosimetry due to the fact that:
Reference:Azangwe et al, Med Phys 41, 072103 (2014) Das IJ et al, TG-106 Med Phys 2008; 35:4186-4215 Kamio & Bouchard; Phys Med Biol 2014;59:4973-5002
Choice A:They have a large signal to noise ratio.
Choice B:The ion recombination effect is negligible.
Choice C:There is no dose perturbation.
Choice D:All of above (A,B,C)
Choice E:None of above
Question 5: What is correct bias (voltage) to apply to micro-detectors to collect readings?
Reference:Das IJ et al, TG-106 Med Phys 2008; 35:4186-4215
Choice A:300 volts and higher.
Choice B:150 Volts.
Choice C:10 Volts.
Choice D:0 volts.
Choice E:It depends on the micro-detector.
Question 6: The correction factor, k fclin, fmsr Qclin, Qmsr defined in IAEA protocol for small field accounts for:
Reference:Alfonso et al, Med Phys 2008; 35:5179-5186.
Choice A:Photon fluence perturbation.
Choice B:Spectral changes (stopping power)
Choice C:Secondary electron perturbation.
Choice D:Combinations of stopping power and various perturbations.
Choice E:Unity for micro-detector.
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