Handheld Gamma-camera for Preoperative Sentinel Lymph Node Localization

This study was performed in several phases. Figure 1 provides an overview of the study procedures and included patients for each phase of the study.Fig. 1

Flowchart of study procedures. Dotted arrow represents patients (n = 15) who underwent both blinded assessment as well as cutaneous marking of the SLNs’ location by handheld gamma-camera and a ⁵⁷Co-penpoint marker. n number, SLN sentinel lymph node

First, the clinical utility of this handheld gamma-camera was evaluated in 17 patients (32%), by assessing whether identified SLNs using lymphoscintigraphy could be detected preoperatively with the handheld gamma-camera (Fig. 2).Fig. 2

Comparison SPECT/CT (a, c) and Crystal Cam handheld gamma-camera images (b, d). Coronal plane of SPECT/CT (a) depicting injection site (*) and two SLNs located in level Ia and level Ib on the left side. Both SLNs (Ia, Ib) and injection site could be visualized within the field-of-view of the handheld gamma-camera (white square, a) (b). Two SLNs as identified by SPECT/CT (c) (sagittal plane; level IIa, III), also detected by handheld gamma-camera (IIa, III) (d)

Subsequently, to evaluate the reliability of SLN identification using the handheld gamma-camera, a blinded comparison was made between preoperative handheld gamma-camera and lymphoscintigraphy outcomes in 36 patients (68%; see ‘Assessment blinded for lymphoscintigraphy’).
Out of those who underwent blinded SLN assessment by handheld gamma-camera (n = 36), the reliability of SLN localization using the handheld gamma-camera and a ⁵⁷Co-penpoint marker was evaluated in 15 patients (42%; see ‘Cutaneous marking location SLNs’).
In all patients (n = 53), the handheld gamma-camera was used complementary to conventional gamma-probe guidance for intraoperative SLN localization (see ‘Surgical procedure’).