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General Clinical Specialties: General Practice: OncologySPECT-CT and Sentinel Node Mapping |
1 Stanford University, Radiology, Stanford, CA 2 Stanford University, Surgery, Stanford, CA
510
Objectives: IHGC imaging can lower false negative rate in SLNB by resolving ambiguities during the use of a non-imaging counting probe (CP). We performed a study to determine if an IHGC: 1) was more sensitive and specific than a CP alone; and 2) could form images of SLNs in 20sec or less.
Methods: A high sensitivity IHGC with a 5 x 5 cm^2 field of view (FOV) was used in conjunction with a hand-held CP. 30 melanoma and 8 breast cancer patients underwent a SLNB protocol with 1) preop lyphoscintigraphy (PLS); 2) localize and record counts from SLN in the OR with CP; 3) image SLN with IHGC in the OR for only 1-20sec; 4) surgically remove that SLN; 5) record counts from SLN ex-vivo with CP; 6) image SLN ex-vivo with IHGC; 7) repeat step 2, until no SLN are found with CP; 8) scan with IHGC to find occult nodes; 9) attempt to re-localized any occult SLN with CP; 10) Compare OR findings of SLN with path results. A true positive (TP) for the CP was defined as > 100 cps in-vivo and ex-vivo. A false negative (FN) for the CP was no-detection in-vivo with CP, but detection of > 5 cps by both IHGC in-vivo and CP ex-vivo. TP for the IHGC was > 5 cps for both IHGC in-vivo and CP ex-vivo. FN for the IHGC was non-detection for the IHGC in-vivo and > 100 cps CP ex-vivo.
Results: PLS localized 67 radioactive SLN (of which 8 were internal mamary nodes). 70 TP and 8 FN resulted using the CP versus 73 TP and 5 FN for the IHGC. OR time was not increased. 14 pathology positive SLN were detected by IHGC(14) and CP(13).
Conclusions: At this point, IHGC is promising but the FN rate was not significantly different than for the CP (p<0.2, for t-test with 38 patients).
Research Support: This work was supported in part by the Whitaker Foundation under Grant No. RG-01-0492
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