Intraoperative Assessment of Tumor Resection Margins in Breast-Conserving Surgery Using 18F-FDG Cerenkov Luminescence Imaging: A First-in-Human Feasibility Study.

In early-stage breast cancer, the primary treatment option for most women is breast-conserving surgery (BCS). There is a clear need for more accurate techniques to assess resection margins intraoperatively, because on average 20% of patients require further surgery to achieve clear margins. Cerenkov luminescence imaging (CLI) combines optical and molecular imaging by detecting light emitted by 18F-FDG. Its high-resolution and small size imaging equipment make CLI a promising technology for intraoperative margin assessment. A first-in-human study was conducted to evaluate the feasibility of 18F-FDG CLI for intraoperative assessment of tumor margins in BCS. Methods: Twenty-two patients with invasive breast cancer received 18F-FDG (5 MBq/kg) 45-60 min before surgery. Sentinel lymph node biopsy was performed using an increased 99mTc-nanocolloid activity of 150 MBq to facilitate nodal detection against the γ-probe background signal (cross-talk) from 18F-FDG. The cross-talk and 99mTc dose required was evaluated in 2 lead-in studies. Immediately after excision, specimens were imaged intraoperatively in an investigational CLI system. The first 10 patients were used to optimize the imaging protocol; the remaining 12 patients were included in the analysis dataset. Cerenkov luminescence images from incised BCS specimens were analyzed postoperatively by 2 surgeons blinded to the histopathology results, and mean radiance and margin distance were measured. The agreement between margin distance on CLI and histopathology was assessed. Radiation doses to staff were measured. Results: Ten of the 12 patients had an elevated tumor radiance on CLI. Mean radiance and tumor-to-background ratio were 560 ± 160 photons/s/cm2/sr and 2.41 ± 0.54, respectively. All 15 assessable margins were clear on CLI and histopathology. The agreement in margin distance and interrater agreement was good (κ = 0.81 and 0.912, respectively). Sentinel lymph nodes were successfully detected in all patients. The radiation dose to staff was low; surgeons received a mean dose of 34 ± 15 µSv per procedure. Conclusion: Intraoperative 18F-FDG CLI is a promising, low-risk technique for intraoperative assessment of tumor margins in BCS. A randomized controlled trial will evaluate the impact of this technique on reexcision rates.

Potent oxadiazole CGRP receptor antagonists for the potential treatment of migraine.

A pharmacophore model was built, based on known CGRP receptor antagonists, and this was used to aid the identification of novel leads. Analogues were designed, modelled and synthesised which incorporated alternative 'LHS' fragments linked via either an amide or urea to a privileged 'RHS' fragment commonly found in CGRP receptor antagonists. As a result a novel series of oxadiazole CGRP receptor antagonists has been identified and the subsequent optimisation to enhance both potency and bioavailability is presented.