Towards intraoperative microCT imaging of breast cancer resections.

Abstract

147 Background: MicroCT analysis of breast cancer resections was shown by Rong et al. [Tang R et al. (2013) The Breast Journal 19(5), 485-489; Tang R et al. (2013) Breast Cancer Research and Treatment 139(2), 311-316] to attain equivalence with pathology-histology in the assessment of positive margin. However, Rong et al. noted that the 14 minute scan cycle time–7 minutes scan, 7 minutes reconstruction–was a potential limitation. Methods: This paper reports the development of microCT instrumentation and software to address this and other technical challenges. These include (a) reducing the scan-reconstruction time, (b) a small desktop footprint, (c) reconciling optimal soft tissue contrast with minimizing artefacts from inserted metal wires and large calcifications, and (d) features to aid hospital workflow such as a barcode reader, an optical camera to photograph the specimen, and process automation. Scans were done with the purpose-built SkyScan1275 table-top microCT scanner, on frozen anonymous archived breast cancer resection samples. Results: Minimum scan time retaining acceptable image quality was 3 minutes. Reconstruction time was reduced to less than a minute by PC graphics accelerators. Scan-reconstruction cycle time can thus be < 4 minutes. A small (105 x 64 cm) desktop footprint with a weight of 160 kg, requiring only a sturdy laboratory desk, has also been attained in this scanner. Artefacts from large calcifications and metal wires were reduced to non-obtrusive levels by scanning with 1mm aluminum filter and software techniques. An automated scan sequence was developed with sample holders recognized electronically in the scanner. On pressing a single button, the scanner automatically goes to the appropriate magnification and sample height, scans the sample, then reconstructs the scan with preset parameters, and finally opens the reconstructed dataset in software for interactive volume-rendered viewing. Sample barcode reading and optical photo taking can be included in this auto-scan sequence. Conclusions: These developments bring microCT nearer to realizing its potential as an intraoperative “back-table” technique in breast cancer surgery to obviate revisions and improve the surgery process and outcome.