Surface Applicator Plan Development Considerations
Source and Surface Applicator
The Surface Applicator is intended to be used on accessible areas of the patient skin or surface, including Intraoperative Radiation Therapy (IORT). The applicators have been designed to deliver a uniform dose (within +/- 15% uniformity at 2 mm deep) for the full range of sizes. The four surface applicators are circular and are 10 mm, 20 mm, 35 mm and 50 mm in nominal size. Treatment areas ranging from 5 mm to 45 mm in diameter (after accounting for field edge) are possible with the full series of applicators. Disposable plastic end caps, which snap on the bottom of the applicator, should always be used. The end cap is used to ensure that the patient surface is flat and orthogonal with respect to the source and applicator.
The design of the applicator is shown in figure J-1. The applicator is designed so that the source tip will be centered above the flattening filter in the correct location and SSD (source to surface distance, which varies for each applicator).
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