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