Calculation of dose received by sensitive organs in breast cancer radiotherapy using day’s method

Abstract

Breast cancer is one of the commonest cancers in Sudan and in early stage treated radically by external irradiation; therefore the main objective of this study was to evaluate the dose received by the critical organs in radical external breast cancer irradiation. These organs include; eye, thyroid, and shoulder joint where they located at the vicinity of the treatment region. The sample of this study consisted of 53 cancer patient treated at the Radiation and isotopes center in Khartoum in the period from may 2011 to march 2012. The data was collected by measuring the distances of these organs from the treatment fields (anterior supraclave and two tangential field), the applied field size, backscatter factor, output, given dose and the tumour dose. The %doses were calculated by using Day’s method which is used to calculate the dose for a point outside the field size. The result of the study showed that the average %dose received by the eye, thyroid and shoulder from the anterior supraclave were equal to 2.4±0.8, 6.2±1.4 and 8.5±1.4 respectively while from the tangential field were 0.5± 0.2, 0.8±0.3 and 0.9±0.4 respectively.