Figure 1.

IMRT beam arrangements used for prostate irradiation: (a) 7‐field technique; (b) conventional 5‐field IMRT (CFIMRT) technique; (c) the opposed matched field (OMF) technique.

The arrangements illustrated in (b) and (c) are used for patients with bilateral MHP. The two posterior oblique beams shown in (b) are also used in (c) but have been removed for clarity. The bladder (orange contour), rectum (green contour), CTV (red colorwash), PTV margin (blue colorwash), and metal hip prostheses (yellow colorwash) are indicated for reference. Note that the CT scans are obtained with a GE LightSpeed