2016 AAPM Annual Meeting
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Session Title: Microdosimeters for Therapy
Question 1: Small field is defined as:
Reference:Das IJ, Ding GX, Ahnesjö A. Small fields: Non-equilibrium radiation dosimetry. Med Phys 2008; 35:206-215
Choice A:Any field smaller than 3x3 cm2.
Choice B:Field that is comparable to focal spot of the machine.
Choice C:Fields that are smaller than detector.
Choice D:Depends on beam energy due to lateral range of secondary electron.
Choice E:Where ratio of detector reading is equal to ratio of dose.
Question 2: 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:Only diode detector as size is small.
Choice C:Small volume ion chamber.
Choice D:Diamond detector.
Choice E:Detector with sensitive volume in order of micron.
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:Small water-equivalent detectors (MicroLion, MicroDiamond, Plastic Scintillators)
Choice B:Edge detector.
Choice C:Pinpoint.
Choice D:MicroMosfet.
Choice E:Any micro-detector.
Question 4: Microdetectors are suited for dosimetry due to:
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:Pion, ion recombination effect is negligible.
Choice B:No dose perturbation.
Choice C:Extremely small volume.
Choice D:Large signal to noise ratio.
Choice E:Bragg-Gray cavity theory concept is valid.
Question 5: What is correct bias (voltage) applied to microdetectors to collect reading?
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:Depends on microdetector.
Question 6: 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 microdetector.
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