ABSTRACT
OBJETIVOS: Determinar la factibilidad de la freehand-SPECT en la identificación de lesiones óseas con captación de 99mTc-HDP evaluando los datos generados mediante la utilización de sistemas de navegación con realidad aumentada y virtual. MATERIAL Y MÉTODOS: Se generaron 21 imágenes 3D utilizando freehand-SPECT con una gammacámara manual en 20 pacientes referidos para gammagrafía ósea con 99mTc-HDP. Las imágenes freehand-SPECT y las gammagrafías fueron comparadas y se analizó el grado de concordancia. Además, se evaluó la factibilidad de navegación hacia las lesiones óseas hipercaptantes. RESULTADOS: En el 86% de los casos freehand-SPECT mostró una buena concordancia con las imágenes correspondientes de la gammagrafía ósea. En lesiones con una señal lesión/fondo de>1,36 freehand-SPECT pudo automáticamente proporcionar puntos de referencia segmentados con finalidad de navegación. En el 14% de los casos (índice lesión/fondo: valor promedio 1,82, rango 1,0-3,4) las imágenes freehand-SPECT mostraron concordancia intermedia debido a que estaban localizadas en regiones anatómicas difíciles o asociadas con una gammagrafía ósea negativa y fueron consideradas como no apropiadas para la navegación dirigida. CONCLUSIÓN: En este estudio piloto, se encontró un 86% de los casos apropiados para propósitos de navegación con una buena concordancia entre freehand-SPECT y la gammagrafía ósea. Un índice lesión/fondo de 1,36 o más facilitó la navegación con freehand-SPECT. La alta calidad de las imágenes generadas con freehand-SPECT potencialmente asegura una exitosa estrategia de navegación para biopsias óseas guiadas
PURPUSE: 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
Subject(s)
Humans , Biopsy, Needle/methods , Bone Diseases/diagnostic imaging , Gamma Cameras , Image-Guided Biopsy/methods , Technetium Tc 99m Medronate/analogs & derivatives , Tomography, Emission-Computed, Single-Photon/methods , Equipment Design , Pilot Projects , Radiopharmaceuticals/pharmacokinetics , Technetium Tc 99m Medronate/pharmacokinetics , Tomography, Emission-Computed, Single-Photon/instrumentation , Whole Body Imaging , Bone Diseases/pathology , Bone Neoplasms/diagnostic imaging , Bone Neoplasms/secondary , Double-Blind MethodABSTRACT
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.
Subject(s)
Biopsy, Needle/methods , Bone Diseases/diagnostic imaging , Gamma Cameras , Image-Guided Biopsy/methods , Technetium Tc 99m Medronate/analogs & derivatives , Tomography, Emission-Computed, Single-Photon/methods , Bone Diseases/pathology , Bone Neoplasms/diagnostic imaging , Bone Neoplasms/secondary , Double-Blind Method , Equipment Design , Humans , Image-Guided Biopsy/instrumentation , Organ Specificity , Phantoms, Imaging , Pilot Projects , Radiopharmaceuticals/pharmacokinetics , Software , Technetium Tc 99m Medronate/pharmacokinetics , Tomography, Emission-Computed, Single-Photon/instrumentation , Whole Body ImagingABSTRACT
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.
