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Program Information

Evaluation of BEBIG HDR 60Co System for AccuBoost Therapy

A Meigooni

M Zehtabian1 , S Sina2 , M Rivard3 , A Soleimani Meigooni4*, (1) Shiraz University, Shiraz, Fars, (2) Shiraz University, Shiraz, Fars, (3) ,Tufts University School of Medicine,Boston, MA, (4) Comprehensive Cancer Center of Nevada, Las Vegas, Nevada


SU-E-T-380 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: In this project, the possibility of utilizing the BEBIG 60Co HDR system for AccuBoostTM treatment has been evaluated.
Methods:Dose distributions in various breast sizes have been calculated for both Co-60 and Ir-192 sources using the MCNP5 code. These calculations were performed in breast tissues with thicknesses of 4cm, 6cm, and 8cm. The initial calculations were performed with the same applicator dimensions as the existing applicators used with the HDR Ir-192 system. The activity of the Co-60 source was selected such that the dose at the breast center was the same as the values from 192Ir. Then, the applicator thicknesses were increased to twice of those used with HDR Ir-192 system, for reducing skin and chest doses by Co-60 system. Dose to breast skin and chest wall were compared for both applicators types, with and without inclusion of a focusing cone at the applicator center.
Results:The results showed that loading HDR Co-60 source inside the thin applicators impose higher doses to breast skin and chest wall compared to the 192Ir source. The area of the chest wall covered by 10Gy when treated by Co-60 with the thin and thick applicators, or treated by Ir-192 with thin applicator are 79cm2, 39cm2, and 3.8cm2, respectively. These values are reduced to 34cm2, 0cm2, and 0cm2 by using the focusing cone. It is worth noting that the breast skin areas covered by the 60Gy isodose line are 9.9cm2 and 7.8cm2 for Co-60 with the thin and thick applicators, respectively, while it is 20cm2 for Ir-192 when no focusing cone is present. These values are 0cm2, 0cm2, and 11cm2 in the presence of the focusing cone.
Conclusion:The results indicate that using Co-60 with the thicker applicators is beneficial because of the higher half-life of Co-60, and the reduced maximum skin dose when compared with Ir-192.

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