<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>A uniform dose to the target site is required with a knowledge of delivered dose, central axis depth dose and beam flatness for successful electron treatment at an extended source to surface distance (SSD). In an extended SSD treatment under dosage of the lateral tissue may occur due to reduced beam flatness. To study the changes in beam characteristics, the depth dose curves, beam flatness and isodose distributions were measured at different SSDs from 100 to 120 cm for clinically used field sizes from (4×4) to (25×25) cm<sup>2</sup> and beam energies ranging from 6 MeV to 20 MeV. Our results suggest that the change in depth dose is minimal except in the buildup region for most energy. In general surface dose is decreased as the SSD increased moderately. It was observed that the loss in beam flatness is significant for smaller fields, higher isodose lines, and lower energies. The penumbra enlarged and the uniformity index reduced with increasing SSD.</p></abstract>

A uniform dose to the target site is required with a knowledge of delivered dose, central axis depth dose and beam flatness for successful electron treatment at an extended source to surface distance (SSD). In an extended SSD treatment under dosage of the lateral tissue may occur due to reduced beam flatness. To study the changes in beam characteristics, the depth dose curves, beam flatness and isodose distributions were measured at different SSDs from 100 to 120 cm for clinically used field sizes from (4×4) to (25×25) cm2 and beam energies ranging from 6 MeV to 20 MeV. Our results suggest that the change in depth dose is minimal except in the buildup region for most energy. In general surface dose is decreased as the SSD increased moderately. It was observed that the loss in beam flatness is significant for smaller fields, higher isodose lines, and lower energies. The penumbra enlarged and the uniformity index reduced with increasing SSD.

Electron beam characteristics at extended source to surface distance for a Clinac-DHX linear accelerator

Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Bangalore, India

Polish Journal of Medical Physics and Engineering

A uniform dose to the target site is required with a knowledge of delivered dose, central axis depth dose and beam flatness for successful electron treatment...

Electron beam characteristics at extended source to surface distance for a Clinac-DHX linear accelerator

Published Online: Sep 22, 2010

Page range: 121 - 133

DOI: https://doi.org/10.2478/v10013-009-0012-x

Keywords
electron beam, beam flatness, uniformity index, beam penumbra, isodose

This content is open access.

Electron beam characteristics at extended source to surface distance for a Clinac-DHX linear accelerator

Published Online: Sep 22, 2010

Page range: 121 - 133

DOI: https://doi.org/10.2478/v10013-009-0012-x

Keywordselectron beam, beam flatness, uniformity index, beam penumbra, isodose

This content is open access.

Keywords
electron beam, beam flatness, uniformity index, beam penumbra, isodose