Freehand-SPECT with 99mTc-HDP as tool to guide percutaneous biopsy of skeletal lesions detected on bone scintigraphy. / Freehand-SPECT con 99mTc-HDP como herramienta para guiar la biopsia percutánea de lesiones esqueléticas detectadas en la gammagrafía ósea.

PURPOSE: To assess the feasibility of using freehand Single Photon Emission Computed Tomography (freehandSPECT) for the identification of technetium-99m-hydroxydiphosphonate (99mTc-HDP) positive bone lesions and to evaluate the possibility of using these imaging data-sets for augmented- and virtual-reality based navigation approaches. MATERIAL AND METHODS: In 20 consecutive patients referred for scintigraphy with 99mTc-HDP, 21 three-dimensional freehandSPECT-images were generated using a handheld gamma camera. Concordance of the two different data sets was ranked. Furthermore, feasibility of segmenting the hotspot of tracer accumulation for navigation purposes was assessed. RESULTS: In 86% of the cases freehandSPECT images showed good concordance with the corresponding part of the scintigraphic images. In lesions with a signal to background ratio (SBR) >1.36, freehandSPECT provided an automatically segmented reference point for navigation purposes. In 14% of the cases (average SBR 1.82, range 1.0-3.4) freehandSPECT images showed intermediate concordance due to difficult anatomical area or negative bone scintigraphy and could not be used as navigation targets. CONCLUSION: In this pilot study, in 86% of the cases freehandSPECT demonstrated good concordance with traditional scintigraphy. A lesion with a SBR of 1.36 or more was suitable for navigation. These high-quality freehandSPECT images supported the future exploration navigation strategies, e.g. guided needle biopsies.

Sentinel node biopsy and lymphatic mapping in penile and prostate cancer.

BACKGROUND: Nodal metastases are linked to poor outcome in men with penile or prostate cancer. Early detection and resection are important for staging and for the prognosis. However, lymphadenectomy is associated with morbidity and may miss metastases when performed solely on the basis of anatomical templates. METHODS: In this article we describe the technique and benefits of sentinel node biopsy (SNB) and provide a review of the literature. RESULTS: Dynamic sentinel node techniques using both radioactive and optical (hybrid) tracers have been proven effective in penile cancer. For prostate cancer, SNB added to extended nodal dissection may further tailor dissection to the highly variable lymphatic drainage patterns in the pelvis. The sensitivity of SNB was found to be superior to conventional imaging methods; however, false-negative SNB procedures can occur and a complementary extensive lymphadenectomy is required to remove additional positive nodes that were not detected in the SNB template. CONCLUSION: SNB is a standard method for early detection of nodal metastases in penile cancer and provides superior diagnostic accuracy to conventional imaging modalities in prostate cancer.