Radioguided surgery with decay: A feasibility study in cervical cancer

Purpose: Radioguided surgery (RGS) is a technique that helps the surgeon to achieve a tumour resection as complete as possible, by means of the intraoperative detection of particles emitted by a radiotracer that bounds to tumoural cells. This study aimed to investigate the applicability of beta-RGS for tumour resection and margin assessment in cervical cancer patients preoperatively injected with [F-18]FDG, by means of Monte Carlo simulations. Methods: Patients were retrospectively included if they had a recurrent or persistent cervical cancer, underwent preoperative PET/CT to exclude distant metastases and received radical surgery. All PET/CT images were analysed extracting tumour SUVmax, background SUVmean and tumour-to-non-tumour ratio. These values were used to obtain the expected count rate in a realistic surgical scenario by means of a Monte Carlo simulation of the beta probe, assuming the injection of 2 MBq/kg of [F-18]FDG 60 min before surgery. Results: Thirty-eight patients were included. A measuring time of similar to 2-3 s is expected to be sufficient for discriminating the tumour from background in a given lesion, being this the time the probe has to be over the sample in order to be able to discriminate tumour from healthy tissue with a sensitivity of similar to 99% and a specificity of at least 95%. Conclusion: This study presents the first step towards a possible application of our beta-RGS technique in cervical cancer. Results suggest that this approach to beta-RGS could help surgeons distinguish tumour margins from surrounding healthy tissue, even in a setting of high radiotracer background activity.