title: Kilovoltage cone-beam CT imaging dose during breast radiotherapy: a dose comparison between a left and right breast setup.
abstract: The purpose of this study was to investigate the delivered dose from a kilovoltage cone-beam computed tomography (kV-CBCT) acquired in breast treatment position for a left and right breast setup. The dose was measured with thermoluminescent dosimeters positioned within a female anthropomorphic phantom at organ locations. Imaging was performed on an Elekta Synergy XVI system with the phantom setup on a breast board. The image protocol involved 120kVp, 140mAs, and a 270° arc rotation clockwise 0° to 270° for the left breast setup and 270° to 180° for the right breast setup (maximum arc rotations possible). The dose delivered to the left breast, right breast, and heart was 5.1mGy, 3.9mGy, and 4.0mGy for the left breast setup kV-CBCT, and 6.4mGy, 6.0mGy, and 4.8mGy for the right breast setup kV-CBCT, respectively. The rotation arc of the kV-CBCT influenced the dose delivered, with the right breast setup kV-CBCT found to deliver a dose of up to 4mGy or 105% higher to the treated breast's surface in comparison with the left breast setup. This is attributed to the kV-CBCT source being more proximal to the anterior of the phantom for a right breast setup, whereas the source is more proximal to the posterior of the patient for a left-side scan.
authors.affiliation: Northern Sydney Cancer Centre, Royal North Shore Hospital, NSW, Australia; Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, NSW, Australia. Electronic address: Alexandra.quinn@health.nsw.gov.au.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Quinn
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, NSW, Australia; School of Physics, University of Sydney, NSW, Australia; Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia; South West Clinical School, School of Medicine, University of New South Wales, Australia.
authors.forename: Lois
authors.initials: L
authors.lastname: Holloway
authors.affiliation: Liverpool and Macarthur Cancer Therapy Centres, NSW, Australia.
authors.forename: Jarrad
authors.initials: J
authors.lastname: Begg
authors.affiliation: Liverpool and Macarthur Cancer Therapy Centres, NSW, Australia.
authors.forename: Vinod
authors.initials: V
authors.lastname: Nelson
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, NSW, Australia; Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Metcalfe
mesh_terms: D001943:Breast Neoplasms / Q000532:radiotherapy*; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D011829:Radiation Dosage
keywords: Breast; Dose; Kilovoltage cone-beam CT