Radiation Dose to Surgical Staff From Positron-Emitter-Based Localization and Radiosurgery of Tumors

Abstract

Surgical tissue characterization based on radiotracer uptake has become much more common in recent years, particularly due to the advent of the sentinel lymph node biopsy technique. Radiolabeled pharmaceuticals are used with hand-held gamma-sensitive probes, which are capable of localizing small tumors and lymph nodes that are first identified via scintigraphy. The radiation safety of such radioguided procedures, which typically employ 99mTc, has been well established. Now, with the emergence of 18F-fluorodeoxyglucose (18FDG) as a widely used tracer for PET imaging of cancer patients, there is increasing interest in the possibility of utilizing 18FDG for intraoperative tumor detection. First, though, the exposure to operating room personnel must be shown to be at a safe level. Due to the short half-life of 18F, the exposure rate will vary significantly with the start time post-injection as well as the duration of the procedure. The aim of this investigation is to determine empirically an exposure rate equation that can be integrated to estimate the exposure to a surgeon and assistants, from patients injected with 18FDG, over an arbitrarily chosen time interval. The study was conducted by measuring the radiation exposure rate from hospital in-patients receiving 18FDG-PET scans at various times from one to seven hours post injection; the empirical equation was determined from the plot of exposure rate vs. time for all patients. The resulting effective dose equivalent for the surgeon for typical values of injected activity, delay time and procedure duration was approximately 60 microSv.

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

“…The low radiation exposure to staff found in this study is in accordance with previously reported exposure levels from 18 F-FDG-guided breast surgery procedures (20,21) and comparable to the radiation dose reported for interventional cardiology procedures (1-50 mSv) (22). The number of 18 F-FDG CLIguided BCS procedures that could be performed in a routine clinical setting depends on the occupational limits on radiation exposure per country (Table 2).…”

Obtaining Adequate Surgical Margins in Breast-Conserving Therapy for Patients with Early-Stage Breast Cancer: Current Modalities and Future Directions

“…Sensitivity and specificity of PET are relatively high for 18 F-FDG-avid breast tumors 100,101. However, because of limited spatial resolution of PET imaging, small tumors (<1 cm) are difficult to detect, whereas breast screening programs and technological developments have led to a considerable reduction in the size of breast cancers being detected 97,102,103.…”

“…Additionally, PET lacks specificity, because normal physiologic uptake of 18 F-FDG can be demonstrated to varying degrees in nonmalignant tissues, such as inflammatory tissue 91. Finally, PET has the disadvantage of high costs and radiation exposure to primary operating personnel during the intraoperative 18 F-FDG PET procedure is expected to be relatively high 101,102…”

Intra-operative ultrasound versus wire-guided localization in the surgical management of non-palpable breast cancer

“…Thus the utility in the context under discussion, nonpalpable lesions, is limited. Add to this the high costs and radiation exposure, and intra-operative PET remains largely an experimental tool [43,44].…”