Detecting breast cancer tissue with diffuse reflectance spectroscopy

Nowadays, the majority of patients with small tumors undergo breast-conserving surgery which aims at conserving the shape of the breast by resecting only a small portion of the breast including the tumor followed by radiation therapy. There is one very important condition that has to be met during breast-conserving surgery in order to minimize the risk of a local recurrence, which is complete removal of the tumor, or in other words, the absence of positive resection margins. Currently, there are no sufficient margin assessment technologies available that can provide the surgeon with real-time feedback on whether margins are positive for tumor.
Diffuse Reflectance Spectroscopy is an optical technology that reflects the composition and morphology of tissue by measuring the interaction between light and tissue. A DRS measurement will provide information on the optical characteristics of tissue which can be used to discriminate different tissue types.
Potentially DRS measurements can help the surgeon in characterizing tissue and thereby provide guidance during breast-conserving surgery. The aim of this thesis was to address some of the challenges that hamper progressing DRS into the OR room for the detection of positive resection margins. First, the optical differences between DRS measurements of healthy tissue and tumor tissue are compared. Second, the influence of tissue status (in vivo or ex vivo) and patient-specific characteristics (i.e. neo-adjuvant chemotherapy) are examined. Furthermore, the ability of DRS to classify measurements of locations with a mixture of tissue types is investigated. Finally, also the feasibility of translating the technology into the clinic is investigated in an in vivo study in which biopsies were acquired with an optical biopsy needle.