A pilot study of N-ammonia cardiac PET imaging to assess subacute cardiotoxicity following adjuvant intensity-modulated radiotherapy for locally advanced breast cancer.

Objective: (1) Assess the feasibility of 13 N-ammonia cardiac PET (13 N-ammonia-PET) imaging in radiotherapy (RT) treatment position in locally-advanced breast cancer (LABC) patients. (2) Correlate pre-/post-RT changes in myocardial flow reserve (MFR) with the corresponding radiation heart dose.

Methods: Ten left-sided LABC patients undergoing Volumetric Modulated-Arc-Therapy (VMAT) to chest wall and regional lymph nodes underwent a rest/stress 13 N-ammonia-PET at baseline and (median) 13 months post-RT.