A three-field monoisocentric inverse breast treatment planning technique without half-beam blocking

Tiezhi Zhang, Joshua T. Dilworth, Ovidiu Marina, Peter Chen, Lisa Benedetti, Qiang Liu

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The purpose of this study was to introduce a three-field monoisocentric inverse treatment planning method without half-beam blocks for breast cancer radiation treatments. Three-field monoisocentric breast treatment planning with half-beam blocks limits the tangential field length to 20 cm. A dual-isocenter approach accommodates patients with larger breasts, but prolongs treatment time and may introduce dose uncertainty at the matching plane due to daily setup variations. We developed a novel monoisocentric, three-field treatment planning method without half-beam blocking. The new beam-matching method utilizes the full field size with a single isocenter. Furthermore, an open/IMRT hybrid inverse optimization method was employed to improve dose uniformity and coverage. Geometric beam matching was achieved by rotating the couch, collimator, and gantry together. Formulae for three-field geometric matching were derived and implemented in Pinnacle scripts. This monoisocentric technique can be used for patients with larger breast size. The new method has no constraints on the length of tangential fields. Compared with the dual-isocenter method, it can significantly reduce patient setup time anduncertainties.

Original languageEnglish
Pages (from-to)246-258
Number of pages13
JournalJournal of applied clinical medical physics
Issue number5
StatePublished - 2015


  • Breast cancer
  • Monoisocentric technique
  • Treatment planning


Dive into the research topics of 'A three-field monoisocentric inverse breast treatment planning technique without half-beam blocking'. Together they form a unique fingerprint.

Cite this