Squelette homotopique 3D pour le traitement et l'analyse du ventricule gauche en SPECT

Des images tomoscintigraphiques sont la représentation 3D de la distribution d'un traceur dans le ventricule gauche (VG). Le but de notre étude est de réussir à quantifier les défauts de fixations (zones d'atténuation) représentatifs d'une pathologie. Le squelette 3D du VG est utilisé pour reconstituer la forme originale du VG. Pour combler les lacunes liées aux pathologies, le squelette est complété conformément à un modèle. Un algorithme fondé sur la théorie de l'incertain (logique floue) utilise le squelette ainsi complété pour générer une nouvelle image avec un contraste plus élevé. Cette nouvelle image peut être plus facilement segmentée, et le VG est considéré dans son intégralité. Le VG peut alors être entièrement quantifié

Scintimammography with technetium-99m methoxyisobutylisonitrile: results of a prospective European multicentre trial.

The aim of the trial was to determine the diagnostic accuracy of scintimmammography with technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) in the detection of primary breast cancer and to verify its clinical usefulness. A total of 246 patients with a suspicious breast mass or positive mammogram were included in this prospective European multicentre trial. At 5 min and 60 min (optional) p.i. two lateral prone images were acquired for 10 min each; 30 min p.i. one anterior image was acquired for 10 min. There were 253 lesions (195 palpable and 58 non-palpable), in respect of which histology revealed 165 cancers and 88 benign lesions. Institutional and blinded read results were correlated to core laboratory histopathology results obtained during excisional biopsy. Diagnostic accuracy for the detection of breast cancer was calculated per lesion. The overall sensitivity and specificity of blinded read scintimammography were 71% and 69%, respectively. For palpable lesions, the sensitivity of blinded read and institutional read scintimammography was 83% and 91%, respectively. Sensitivity was not dependent on the density of the breast tissue. Invasive ductal and invasive lobular cancers showed similar sensitivity. The sensitivity and specificity of mammography were 91% and 42%, respectively, and did not depend on the tumour size. In 60% of false-negative mammograms, 99mTc-MIBI was able to diagnose malignancy (true-positive). High-quality imaging with 99mTc-MIBI has a high diagnostic accuracy for the detection of primary breast cancer. Used as a complementary method, scintimammography with 99mTc-MIBI can help to diagnose breast cancer at an earlier stage in patients with dense breasts

3-dimensional homotopic skeleton for the treatment and analysis of the left ventricule in ERIM spect

National audienc

Assessment of a simulation software for scintillation detector

Aim: A Monte Carlo code based on GEANT 3.21 and Linux platform has been developed and adaptated to simulate gamma detectors dedicated to specific scintigraphic applications. Materials and methods: GEANT 3.21 is freely available at the CERN program library. It has been written for simulating the interactions of particles with energy greater than 10keV. The energy of the gamma rays used in scintigraphic imaging never exceeds 511keV. Interaction cross- sections for energies between 10keV and 10MeV and three media of interest obtained with this program have been compared with data available on the NIST web site. A gamma peroperative hand-held probe has then been simulated. Sensitivity and spatial resolution were evaluated. Results: The high standard deviation for total attenuation coefficient is 4.7% with an uncertainty around 4% given by NIST. The good results obtained have allowed us to go farther in computer programming. In the hope of integrating all the detection lines new routines have been introduced for the simulation of scintillation photons and optical effects. First simulated optical spots have a diameter of 2.5mm (FWHM) for a 6mm NaI(Tl) thickness and gamma rays of 140keV. Conclusion: The code was recently improved with the implementation of a photomultiplier tube and the algorithm for the image reconstruction. In this way, the computed image can be compared with optical image obtained just before the photocathode to improve algorithm. Soon, simulation results will be tested with a mini gamma- camera prototype

3-dimensional homotopic skeleton for the treatment and analysis of the left ventricule in ERIM spect

National audienc