answers Newest RATED A+ 2025/2026
The dose received at isocenter in a CBCT prior to treatment is approximately ____ cGy - Correct
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Answers 2-4 cGy
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II! for cranial stereotactic radiosurgery, accuracy and reproducibility should be on the order of
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II! ____mm - Correct Answers 2 II! II! II! II! II! II! II! II! II!
II! for an implant, for same initial dose rate, the required total activity of I-125 will be (greater or
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II! less) than that needed of Ir-192 - Correct Answers greater- lower exposure rate constant
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II! which isotope is created in a cyclotron? - Correct Answers F-18
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II! Patients can be released from the hospital when the projected dose to individuals around the
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II! patient is less than or equal to _____ - Correct Answers 5 mSv
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II! In hyperthermia the tumor and its vicinity are heated using___ - Correct Answers microwave
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II! radiation
II! for a 24x24 parallel opposed isocentric 6MV plan, the patient's AP thickness can be up to ____cm
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II! if the max tissue dose is not to exceed 110% of the dose at isocenter - Correct Answers 25
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II! btw. universal and dynamic wedges, which requires more MU? - Correct Answers Universal
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II! btw universal and dynamic wedges, which makes a more penetrating depth dose? - Correct
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II! Answers universal II! II! II! II! II!
, II! for which does the wedge transmission factor vary with field size? universal or dynamic? -
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II! Correct Answers both II! II! II! II! II! II!
II! what is the WAHA equation? - Correct Answers WA=(180-HA)/2
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II! Equation for the gap on the skin surface for a pair of matched fields at some depth - Correct
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II! Answers g=(d/SAD)*(C1+C2)/2 II! II! II! II! II!
II! Equation for the RPO gantry angle given the LAO gantry angle - Correct Answers
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II! RPO=LAO+180-(2xdivergence angle) II!
II! flattening filters flatten the beam at a depth of - Correct Answers 10cm II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II! II!
II! what two factors are important in selecting a PDD table from literature for a superficial x-ray unit?
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II! - Correct Answers HVL and SSD
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II! dose under a 1.5cm width block of 5 HVL thickness in a 15x15 6MV photon beam at 5 cm depth
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II! due to transmission plus scatter is approximately ____% of the dose in the open beam - Correct
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II! A patient treated with 6MV tangential breast fields, the dose to the ovaries 20cm inferior to the
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II! fields is approximately ___% of the prescribed dose - Correct Answers .5%
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II! how far from the field edge does 5% occur for a 6MV beam? - Correct Answers 2cm
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II! how quickly are electrons attenuated in lead? - Correct Answers 2MeV/mm
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II! how much more cerrobend is needed than lead for electrons? (%) - Correct Answers 20%
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