Question 1: The definition of a small field:
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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.
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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)
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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:
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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
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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?
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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. |