Gap application results for adjacent electron beams treatment

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 269; no. 24; pp. 3141 - 3144
• Main Authors: Sampaio, Francisco G.A., Del Lama, Lucas S., Petchevist, Paulo C.D., Moreira, Marcos V., Almeida, Adelaide de
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-12-2011
• Subjects: Adjacent electron beams; Computer simulation; Electron beams; Fricke Xylenol Gel; Gaps; Hot spots; Ionizing radiation; Monte Carlo method; Monte Carlo methods; Photons; Tumors; Adjacent electron beams; Monte Carlo method; Fricke Xylenol Gel
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2011.04.097

Nowadays, electron beams from high-energy linear accelerators (LINAC) are widely used in a variety of radiotherapy treatments being suitable especially for superficial tumors. Since this sort of ionizing radiation has stopping power higher than photons, deeper and healthier tissues can be preserved. On the other hand, when applying adjacent electron beams, “hot” spots can be observed, due to penumbra and/or scattering, contributing to the increase of the absorbed dose in the target volume. In this sense, the objective of this work was to investigate the effects of parallel adjacent electron beams using the chemical dosimeter Fricke Xylenol Gel (FXG) and compare the experimental results with ones acquired using Monte Carlo simulation. Thus, 10
×
10, 15
×
15 and 20
×
20
cm
2 fields were irradiated with 5, 8 and 10
MeV electron beams applying different gap widths. The experimental results and the simulations indicated overdose values up to 40% from the prescribed one for the specific tumor. This demonstrates that specific gaps are necessary in the case of treatments with parallel adjacent electron beams in order to prevent overdoses in the depth of interest.