Quantitative Targeting and Radiation Therapy of Breast Cancer using a Dedicated Breast Computed Tomography Platform.

摘要

Dedicated breast computed tomography (bCT) is a fully tomographic cone beam x-ray based imaging modality that generates three-dimensional images of the breast. During a bCT scan, the patient lies prone and each breast is imaged, one at a time, in a pendant geometry without compression. While most research has focused on the potential of bCT for diagnostic imaging of the breast, the bCT platform may play a role in other phases of breast cancer management including the delivery of image-guided therapies.;Image-guidance is particularly useful in verifying treatment accuracy and monitoring response to therapy. Currently, quantification of tumor size and response to therapy are given by linear measurements; however, there is a push towards three-dimensional evaluation of tumor volume. The accuracy and precision of tumor volumetry using computed tomography were established. The potential of bCT as a quantitative imaging modality was demonstrated through an initial evaluation of contrast-enhanced bCT (CE-bCT), using injected iodine-based contrast medium. Lesion enhancement at CE-bCT was quantified and the differential enhancement observed between benign and malignant lesions was supported as a metric to aid in the detection and diagnosis of breast cancer.;Upon identifying the location and extent of disease, image-guided radiation therapy (IGRT) can be delivered on the bCT platform. The feasibility of external beam radiation therapy using kilovoltage x-rays (kV-EBRT) and rotational therapy within the geometric constraints of the bCT platform was demonstrated through Monte Carlo simulation. Dose distributions were generated for whole breast irradiation (WBI), partial breast irradiation (PBI), and dose painting. A preliminary treatment planning algorithm was developed to determine the optimal beam intensities and collimation widths for WBI through kV-EBRT on a bCT platform.;As a high-resolution tomographic imaging system, the bCT platform is ideally suited for quantitative tumor targeting and delivery of IGRT. The use of the same platform for both tumor targeting and therapy may provide more accurate treatment delivery and shorter treatment times. Overall, the breast CT platform may be best commissioned in women's health clinics as a multimodality system aiming to increase access to procedures needed for early detection, diagnosis, and treatment of breast cancer.