A commissioning procedure for breast intracavitary electronic brachytherapy systems

Jessica Hiatt,Edward Sternick,Gene Cardarelli,David Wazer,Jaroslaw Hepel

doi:10.1120/jacmp.v9i3.2775

Jessica Hiatt, Edward Sternick + Show 3 more

Open Access

https://doi.org/10.1120/jacmp.v9i3.2775

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Abstract

In this work, we report a comprehensive quality assurance (QA) process for the commissioning of an Electronic Brachytherapy (EB) system at one of the first U.S. sites to apply the device clinically. Thus far, EB systems have been released only for intracavitary breast treatments. As such, EB as an Accelerated Partial Breast Irradiation (APBI) treatment modality is relatively unstudied and is unfamiliar to many medical physicists. We present our documented experience as a guide for other institutions' EB commissioning process. Our tests included eight elements: A) well‐chamber constancy, B) beam stability, C) source positional accuracy, D) output stability, E) timer linearity, F) dummy marker/source position coincidence, G) controller functionality and safety interlocks, and H) treatment planning data verification following the AAPM TG‐43 recommendations. Together with TG‐43, our methodology provides a comprehensive EB system check for medical physicists commissioning such a device.PACS Numbers: 87.53.Jw, 87.53.Xd

Highlights

For patients with early-stage breast cancer, breast conservation therapy (BCT) has become the standard of care
A number of clinical studies [1,2,3,4] have shown that most ipsilateral breast recurrences after BCT arise in the peripheral lumpectomy cavity, implying that whole breast irradiation might be unnecessary for these patients
The report of the American Association of Physicists in Medicine (AAPM) Task Group 43(10-11) offered recommendations for high dose rate (HDR) brachytherapy quality assurance and dose calculations and provided guidance for the tests we designed for commissioning the Xoft Axxent System

Summary

Introduction

For patients with early-stage breast cancer, breast conservation therapy (BCT) has become the standard of care. Traditional BCT consists of a lumpectomy followed by a daily treatment course of whole breast external beam irradiation for approximately six weeks. A number of clinical studies [1,2,3,4] have shown that most ipsilateral breast recurrences after BCT arise in the peripheral lumpectomy cavity, implying that whole breast irradiation might be unnecessary for these patients. The practice of treating only a limited volume of breast tissue surrounding the lumpectomy cavity (1 to 2 cm for patients with negative margins) has been introduced. This type of treatment is termed Accelerated Partial Breast Irradiation (APBI). Because the treated volume is relatively small with APBI, the dose per fraction delivered can be increased significantly, and the overall treatment time reduced to one week

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