title: SPECT analysis of cardiac perfusion changes after whole-breast/chest wall radiation therapy with or without active breathing coordinator: results of a randomized phase 3 trial.
abstract: OBJECTIVE
  Cardiac muscle perfusion, as determined by single-photon emission computed tomography (SPECT), decreases after breast and/or chest wall (BCW) irradiation. The active breathing coordinator (ABC) enables radiation delivery when the BCW is farther from the heart, thereby decreasing cardiac exposure. We hypothesized that ABC would prevent radiation-induced cardiac toxicity and conducted a randomized controlled trial evaluating myocardial perfusion changes after radiation for left-sided breast cancer with or without ABC.
  
  
  METHODS
  Stages I to III left breast cancer patients requiring adjuvant radiation therapy (XRT) were randomized to ABC or No-ABC. Myocardial perfusion was evaluated by SPECT scans (before and 6 months after BCW radiation) using 2 methods: (1) fully automated quantitative polar mapping; and (2) semiquantitative visual assessment. The left ventricle was divided into 20 segments for the polar map and 17 segments for the visual method. Segments were grouped by anatomical rings (apical, mid, basal) or by coronary artery distribution. For the visual method, 2 nuclear medicine physicians, blinded to treatment groups, scored each segment's perfusion. Scores were analyzed with nonparametric tests and linear regression.
  
  
  RESULTS
  Between 2006 and 2010, 57 patients were enrolled and 43 were available for analysis. The cohorts were well matched. The apical and left anterior descending coronary artery segments had significant decreases in perfusion on SPECT scans in both ABC and No-ABC cohorts. In unadjusted and adjusted analyses, controlling for pretreatment perfusion score, age, and chemotherapy, ABC was not significantly associated with prevention of perfusion deficits.
  
  
  CONCLUSIONS
  In this randomized controlled trial, ABC does not appear to prevent radiation-induced cardiac perfusion deficits.
authors.affiliation: Johns Hopkins Medical Institution, Baltimore, Maryland. Electronic address: zellari@jhmi.edu.
authors.forename: Richard
authors.initials: R
authors.lastname: Zellars
authors.affiliation: University of Washington Medical Center, Seattle, Washington.
authors.forename: Paco E
authors.initials: PE
authors.lastname: Bravo
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Erik
authors.initials: E
authors.lastname: Tryggestad
authors.affiliation: Hahnemann University, Philadelphia, Pennsylvania.
authors.forename: Kari
authors.initials: K
authors.lastname: Hopfer
authors.affiliation: Johns Hopkins Medical Institution, Baltimore, Maryland.
authors.forename: Lee
authors.initials: L
authors.lastname: Myers
authors.affiliation: Johns Hopkins Medical Institution, Baltimore, Maryland.
authors.forename: Abdel
authors.initials: A
authors.lastname: Tahari
authors.affiliation: Johns Hopkins Medical Institution, Baltimore, Maryland.
authors.forename: Fariba
authors.initials: F
authors.lastname: Asrari
authors.affiliation: Johns Hopkins Medical Institution, Baltimore, Maryland.
authors.forename: Harvey
authors.initials: H
authors.lastname: Ziessman
authors.affiliation: Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Garrett-Mayer
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D062485:Breath Holding; D003326:Coronary Circulation / Q000502:physiology / Q000528:radiation effects*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000528:radiation effects*; D004867:Equipment Design; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D009068:Movement; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D012119:Respiration; D013147:Spirometry / Q000295:instrumentation*; D035441:Thoracic Wall; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult