J Korean Soc Ther Radiol.  1994 Jun;12(2):263-267.

Dosimetry of Irregular Field Using Thermoluminescence Dosimetry

• Lee JY
• Park KR
• Kim KJ

Abstract

In clinical radiotherapy, the use of wide and irregular field techniques frequently results in considerable tumor dose inhomogeneity because of, the variation in physical characteristics of irradiated volumes. This report describes an analysis of the dosimetry of the irregular fields such as radiation fields for Hodgkin's disease(mantle filed), esophageal cancer, and lung cancer when a 6 MV and a 15 MV linear accelerators are utilized. Doses were measured in an Rando phantom using methods of thermoluminescence dosimetry(TDL), and were calculated by radiotherapy planning computer system with the Clarkson's method for calculation of a irregular field. A dose variation of 5-22%, 6-9%, 6-14% were found in the mantle field, esophageal cancer field, lung cancer field respectively. Higher doses occurred in the superior portion of the irregular field. The sites of maximum dose variation were the supraclavicular and the upper spinal cord region. To adjust for these substantial differences, a compensator or a shrinking filed technique should be adopted.

Keyword

Irregular field; Dosimetry; TLD

MeSH Terms

Computer Systems
Esophageal Neoplasms
Lung Neoplasms
Particle Accelerators
Radiotherapy
Spinal Cord