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The patient has a metastatic lesion from T-12 due to metastatic lung disease. The oncologist orders that the patient be treated to a depth of 6.75 cm using a non-isocentric technique. The field is 9.25 cm x 15.4 cm. The patient is able to lie supine and the AP/PA separation is 32.6 cm.  The dosimetrist has produced a treatment plan that calls for a single field to the PA on the Varian Trilogy at the machine’s isocenter, which is 100 cm. What is the AP SSD?

The simulation therapist will use which of the following anatomical structures to alleviate pelvic rotation, which aids in treatment planning and reproducibility? 

Foaming agents, such as __________________________, have become widely used as an immobilization device.

Extra Credit: IGRT Module When patient tracking for motion and patient adjustments are performed during the treatment, it is called

The oncologist asks for a field shift of 1.0 cm posteriorly, what direction will the table be moved and assume patient is in a supine position?

Extra Credit: IGRT Module Which of the following can lead to random sources of patient set up errors that vary from fraction to fraction?  1. Organ stability 2. Anatomic changes 3. Image-guidance errors

Which of the following is the weakest link in treatment planning?

The planned target volume will contain margins for geometric uncertainties, such as:

The light field on the linear accelerator is intended to represent

Source axis distance is measured from the _______________ to a/the ________________ around which the gantry rotates 360 degrees.