Evaluation of BEBIG HDR 60 Co system for non-invasive image-guided breast brachytherapy

Abstract

PurposeHDR 60Co system has recently been developed and utilized for brachytherapy in many countries outside of the U.S. as an alternative to 192Ir. In addition, the AccuBoost® technique has been demonstrated to be a successful non-invasive image-guided breast brachytherapy treatment option. The goal of this project is to evaluate the possibility of utilizing the BEBIG HDR 60Co system for AccuBoost treatment. These evaluations are performed with Monte Carlo (MC) simulation technique.Material and methodsIn this project, the MC calculated dose distributions from HDR 60Co for various breast sizes have been compared with the simulated data using an HDR 192Ir source. These calculations were performed using the MCNP5 code. The initial calculations were made with the same applicator dimensions as the ones used with the HDR 192Ir system (referred here after as standard applicator). The activity of the 60Co source was selected such that the dose at the center of the breast would be the same as the values from the 192Ir source. Then, the applicator wall-thickness for the HDR 60Co system was increased to diminish skin dose to levels received when using the HDR 192Ir system. With this geometry, dose values to the chest wall and the skin were evaluated. Finally, the impact of a conical attenuator with the modified applicator for the HDR 60Co system was analyzed.ResultsThese investigations demonstrated that loading the 60Co sources inside the thick-walled applicators created similar dose distributions to those of the 192Ir source in the standard applicators. However, dose to the chest wall and breast skin with 60Co source was reduced using the thick-walled applicators relative to the standard applicators. The applicators with conical attenuator reduced the skin dose for both source types.ConclusionsThe AccuBoost treatment can be performed with the 60Co source and thick-wall applicators instead of 192Ir with standard applicators.

A comparative assessment of inhomogeneity and finite patient dimension effects in 60 Co and 192 Ir high-dose-rate brachytherapy

“…Besides the introduction of image-based dose calculation algorithms for 192 Ir, TG-43 remains the prevalent method for the clinical treatment planning dosimetry in HDR brachytherapy applications. While the equivalence of 60 Co and 192 Ir brachytherapy has been established in a number of studies in the literature [ 1 , 2 , 3 , 4 , 5 , 6 , 8 , 10 , 11 , 12 ], the relative effects of inhomogeneities and patient specific scatter conditions have not been considered. These effects were studied retrospectively in this work, through the comparison of TG-43 based dosimetry with corresponding MC results in groups of clinically equivalent plans with 60 Co and 192 Ir HDR sources for breast, esophageal, and cervical treatments.…”

“…This development led to several comparative studies published in the literature. These include comparative evaluations of acute toxicity in gynecological cancer [ 1 , 2 ], and dosimetry studies ranging from single source dosimetry comparison [ 3 , 4 , 5 ] to comparisons of dose distributions in gynecological [ 4 , 5 , 6 , 7 ], prostate [ 8 ], skin [ 9 ], and breast [ 10 , 11 , 12 ] HDR brachytherapy treatments using different techniques. In a comprehensive dosimetry study, Palmer et al .…”

Comparison of 192Ir, 169Yb, and 60Co high‐dose rate brachytherapy sources for skin cancer treatment

“…Lymperopoulou et al had shown that the plan quality with 169 Yb at least is equivalent to 192 Ir source irrespective of the prostate volume. It was also shown that, by modifying the applicator, the HDR 60 Co afterloading system can be a good alternative to the HDR 192 Ir, delivering similar dose distributions in breast cancer patients . Inverse optimization planning for cervical cancer using the 192 Ir, 169 Yb, and 60 Co sources with a tungsten alloy shielded direction‐modulated‐brachytherapy (DMBT) tandem applicator showed that 169 Yb source generated better plans for larger target volumes.…”

“…The Monte Carlo N-Particle code (MCNP) version 6, 26 which has been successfully used in brachytherapy dosimetry by various investigators 4,8,10,15,19 is used in this study. The cross-sections used in these simulations were based on ENDF/B-VI.8 libraries.…”

“…2 Currently, there are various 192 Ir-based HDR remote afterloading systems available in the market. 14 In addition, new interest in the use of other HDR sources, either with high energy sources (e.g., 60 Co in the ECKERT & Ziegler BEBIG GmbH afterloading machine) [14][15][16] and/or middle energy sources (e.g., 169 Yb with dual-source Flexitron after-loading system) 14 are being developed. Although the TG-43 17 based dosimetric characteristics of the 169 Yb 18-21 and 60 Co 18,19,22,23 sources have been evaluated, their clinical applications have not been fully explored, particularly in North America.…”