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A right sided breast cancer is being treated with tangential fields with a hinge angle of 150 degrees. If the gantry angle for the medial tangent is 29 degrees, what is the gantry angle for the lateral tangent?

How much bolus is needed to completely eliminate the skin sparing effect of a 10 MV photon beam?

The half-life of Cesium-131 is:

A batch of Iodine-125 seeds is shipped to a hospital with an activity of 790 mCi. The seeds are received 8 days after they were shipped. What is the activity upon reception? 

Divergence causes _______ in field size as the distance from the source increases.

A left sided breast cancer is being treated with tangential fields with a hinge angle of 180 degrees. If the gantry angle for the medial tangent is 310 degrees, what is the gantry angle for the lateral tangent?

Low-dose-rate brachytherapy refers to treatments with dose rates:

A bolus may:a.    Increase the surface dose by decreasing the skin sparingb.    Compensate for surface irregularitiesc.    Correct for internal tissue heterogeneitiesd.    Fill air gaps/cavities

A SCLC patient is receiving prophylactic cranial irradiation with a 10 MV beam. The dose per fraction is 180 cGy and is to be delivered via equally weighted POP lateral fields using a total of 275 monitor units. If the entire left lateral field was delivered, calculate the total dose delivered if the linac terminated after delivering 112 monitor units to the right lateral field.

Every year, a new decayed value must be determined for the clinical use of cesium-137 tubes. The decay is always calculated from the original assayed value obtained when the source was received. This particular source was received on May 18th, 2017 and upon reception, the activity was 105.3 mCi. You plan to use this source on May 18th, 2021. What will the activity of this source be on the day you plan to use it?