title: Performance metrics of an optical spectral imaging system for intra-operative assessment of breast tumor margins.
abstract: As many as 20-70% of patients undergoing breast conserving surgery require repeat surgeries due to a close or positive surgical margin diagnosed post-operatively [1]. Currently there are no widely accepted tools for intra-operative margin assessment which is a significant unmet clinical need. Our group has developed a first-generation optical visible spectral imaging platform to image the molecular composition of breast tumor margins and has tested it clinically in 48 patients in a previously published study [2]. The goal of this paper is to report on the performance metrics of the system and compare it to clinical criteria for intra-operative tumor margin assessment. The system was found to have an average signal to noise ratio (SNR) >100 and <15% error in the extraction of optical properties indicating that there is sufficient SNR to leverage the differences in optical properties between negative and close/positive margins. The probe had a sensing depth of 0.5-2.2 mm over the wavelength range of 450-600 nm which is consistent with the pathologic criterion for clear margins of 0-2 mm. There was <1% cross-talk between adjacent channels of the multi-channel probe which shows that multiple sites can be measured simultaneously with negligible cross-talk between adjacent sites. Lastly, the system and measurement procedure were found to be reproducible when evaluated with repeated measures, with a low coefficient of variation (<0.11). The only aspect of the system not optimized for intra-operative use was the imaging time. The manuscript includes a discussion of how the speed of the system can be improved to work within the time constraints of an intra-operative setting.
authors.affiliation: Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC, 27708, USA. tmb14@duke.edu
authors.forename: Torre M
authors.initials: TM
authors.lastname: Bydlon
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Kennedy
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Richards
authors.forename: J Quincy
authors.initials: JQ
authors.lastname: Brown
authors.forename: Bing
authors.initials: B
authors.lastname: Yu
authors.forename: Marlee K
authors.initials: MK
authors.lastname: Junker
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gallagher
authors.forename: Joseph
authors.initials: J
authors.lastname: Geradts
authors.forename: Lee G
authors.initials: LG
authors.lastname: Wilke
authors.forename: Nimmi
authors.initials: N
authors.lastname: Ramanujam
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D003198:Computer Simulation; D003952:Diagnostic Imaging / Q000295:instrumentation* / Q000592:standards*; D005260:Female; D006801:Humans; D007430:Intraoperative Care / Q000295:instrumentation*; D009010:Monte Carlo Method; D055096:Optical Devices; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D013057:Spectrum Analysis / Q000295:instrumentation*