Purpose: Although portable gamma cameras (PGCs) have been helpful to depict sentinel nodes (SNs), sometimes nuclear physicians or surgeons have difficulties to interpret PGC images because of the lack of anatomical information. The aim of the present study was to develop and clinically test the prototype of a new portable hybrid camera (PHC), which adds optical to γ-imaging.
Methods: In 2 hospitals, the existing PGC (Sentinella S102; Oncovision) was upgraded with an optical module (BB2-08S2C-25; Point Grey Research) to build a PHC. Preoperative PHC overview images (positioned at 15 cm distance) and close-up image (position at <5 cm distance) were obtained from 25 patients (12 melanoma, 2 oral cavity, and 11 breast cancer) after conventional lymphoscintigraphy. Errors in the optical image coregistration were evaluated with a 5-mm accuracy for each patient.
Results: Conventional lymphoscintigraphy and the close-up PHC images depicted 55 SNs in total. In the PHC overview images, the optical module offered fused optical and γ-imaging indicating the image field of view and anatomical SN locations. Average optical image coregistration errors were 1.0 cm (range, 0-2.0 cm).
Conclusions: Fused optical and γ-imaging with the prototype PHC is technically feasible and helpful for the image interpretation. The optical image visualizes the γ-image field of view, enabling SN localization in an anatomical context in a preoperative setting; however, for the operating room, the use of its optical component needs to be additionally adjusted.