Reducing scatter radiation to the contralateral breast with a mobile, conformal shield during breast cancer radiotherapy

Roger M. Macklis, Richard L. Crownover, Joseph Crowe, Twyla Willoughby, Jason Sohn

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

During a standard course of breast radiotherapy, the contralateral breast generally receives ~2.5 to 6.0 Gy of scattered radiation. Although most studies have not found an overall increase in metachronous contralateral breast cancers in patients undergoing radiotherapy, a cohort of younger women may be genetically more susceptible to radiation-induced breast cancers and may thus be adversely affected by the scattered radiation. We are attempting to develop a simple, convenient, effective mechanism for minimizing the scattered radiation to the contralateral breast during the process of clinical breast radiotherapy. We therefore designed a conformal, platform- based breast shield consisting of 2.5 cm of molded lead in a mobile counterweighted polystyrene casing. This shield was intended to serve as a physical barrier to prevent both low and high energy scattered photons from the medial and lateral tangential fields. We conducted a prospective trial of 20 women, each woman serving as her own control. Each woman received breast radiotherapy with and without shield, and an array of thermoluminescent dosimeters was positioned across the contralateral breast to evaluate the in vivo dosimetry and the impact of the breast shield on surface absorption of scattered radiation. We found that the use of the breast shield reduced the median dose of scattered radiation by ~60% (p < 0.0001). This represented a median dose reduction of ~300 cGy at the nipple. The shield was easily positioned and added <1 min to daily setup time. We conclude that the use of this sort of surface barrier shielding technique was feasible, effective, and practical for clinical use. The degree of scatter reduction accomplished through the use of this breast shield may be biologically significant, especially for those patients with biologic or epidemiologic risk factors that may predispose them to the development of radiogenic breast cancers.

Original languageEnglish (US)
Pages (from-to)419-425
Number of pages7
JournalAmerican Journal of Clinical Oncology: Cancer Clinical Trials
Volume22
Issue number4
DOIs
StatePublished - Aug 1 1999
Externally publishedYes

Keywords

  • Breast cancer
  • Radiation protection
  • Radiotherapy
  • Second malignant neoplasms

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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