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What is the range in soft tissue of a 12 MeV electron beam?

Which of the following limited the use of orthovoltage x-ray machines for radiation therapy?

USE HANDOUT TABLES FOR THE FOLLOWING CALCULATIONA patient is treated on a 6 MV linac treatment machine at 100 cm SSD to his left hip.  The patient is supine and is being treated through a single field.  The collimator setting is 17 x 12 cm.  Some blocking is used to shape the field and the EFS is determined to be 12 x 12 cm.  The blocks are mounted on a slotted lucite tray which is       5 mm in thickness.  The prescription states that a dose of 3000 cGy is to be delivered to a depth of 5 cm in 10 fractions.  Calculate the MUs per fraction.Calculate the treatment time.

When a patient is treated with a single field, the dose at Dmax, should be calculated and recorded due to which of the following?

Which of the following describes where the field size is defined in a non-isocentric approach?

A patient is treated on the 6 MV linear accelerator treatment machine at 100 cm SAD.  The treatment SSD is 90 cm.  The prescription states that a dose of 4000 cGy is to be delivered to a depth of 10 cm in 20 fractions with an AP/PA treatment field arrangement.  If the patient’s spinal cord lies at a depth of 6 cm beneath the patient’s posterior skin surface, what is the depth to the spinal cord from the anterior skin surface?

Which of the following best describes the distance between the entrance and exit points?

When multiple MV photon beams are used, the dose at Dmax  is normally

2 posterior spine fields are required to treat a patient.  They are treated with 6 MV and to a depth of 7 cm.  One field measures 8 x 23 cm at 112 SSD.  Another field measures 8 x 19 cm at 110 SSD.  What is the required gap needed for this treatment?

Which of the following are considered when designing fields and beam arrangements?  (Select all that apply)