2.1. Patients

Images were acquired as part of a phase I/II clinical trial called SIGNAL involving early stage breast cancer patients [2]. At the time of tumour core biopsy, a surgical clip was placed adjacent to or within the tumour. Patient data was acquired from two cohorts of patients and patient demographics are given in Table 1. The first cohort is from patients treated with neoadjuvant 21 Gy/1 fraction SABR and who received lumpectomy within approximately 1-week of SABR. The second cohort were from a protocol where patients were randomly assigned to either 21 Gy/1 fraction or 30 Gy/3 fractions every other day, with both groups receiving lumpectomy at approximately 3 weeks post-SABR. All patients received MRI (including DCE-MRI) prior to SABR for tumor delineation in SABR planning. In addition, patients were offered the opportunity to participate in a sub-study which involved post-SABR MRI as close to the lumpectomy as possible. The protocols, including post-SABR MRI, were approved by the Western University Human Subjects Research Ethics Board.

Study/patient information, image timing and SABR treatment scheme separated by group. Note that for the 3 fraction patients, imaging time post-treatment is the time delay from the conclusion of radiation therapy to the MRI scan.

FX = fraction, L / R = Left or right sided breast affected