Rôle potentiel de la tomographie par émission de positons couplée à la tomodensitométrie (TEP-TDM) au 18F-fluoro-désoxy-glucose ([18F]-FDG) dans l'imagerie des tumeurs urothéliales

BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Impact diagnostique de la TEMP-TMD dans l'exploration des tumeurs endocrines

BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

An abbreviated therapy-dosimetric equation for the companion diagnostic/therapeutic [64/67Cu]Cu-SARTATE

International audienceIn a preclinical model of neuroblastoma, Dearling et al. recently demonstrated the potential interest for a theranostic approach of [64/67Cu]Cu-SARTATE for the detection and treatment of SSTR2-positive neuroblastoma lesions in pediatric patients whose widespread metastases survive initial therapy as minimal residual disease (MRD). MRD may be detected by [64Cu]Cu-SARTATE and subsequently treated by [67Cu]Cu-SARTATE. Since therapeutic dosimetry estimation of the latter agent from the uptake of the former one in the initial diagnostic scan was not addressed, the present theoretical commentary proposes the derivation of an abbreviated therapy-dosimetric equation for the companion diagnostic/therapeutic [64/67Cu]Cu-SARTATE that might be of interest for future clinical theranostic practice

SUVpeak performance in Lung Cancer: Comparison to Average SUV from 40 Hottest Voxels

The performance of an average standard uptake value (SUV) over a 1-mL-volume sphere within an (18)F-FDG-positive lesion resulting in the highest possible value (SUVpeakW), was compared to that of an average SUV computed from the 40 hottest voxels, irrespective of their location within the lesion (SUVmax-40). METHODS A PET dynamic acquisition performed in 20 lung cancer lesions yielded for each SUV metric its mean value, relative measurement error and repeatability (MEr-R). RESULTS SUVpeakW mean value was significantly 9.66% lower than that of SUVmax-40 (P<0.0001). SUVpeakW and SUVmax-40 MEr-R were significantly lower than MEr-R of SUVmax (the hottest voxel): 9.35-13.21%, 8.84-12.49% versus 13.86-19.59% respectively (95%-CL; P<0.0001). Although being marginal, SUVpeakW MEr-R were not significantly greater than SUVmax-40 MEr-R (P = 0.086). CONCLUSION SUVmax-40 is more likely to represent the most metabolically active portions of tumors than SUVpeakW, with close variability performance

Improvement of in Vivo Quantification of [123I]-Iodobenzovesamicol in Single-Photon Emission Computed Tomography/Computed Tomography Using Anatomic Image to Brain Atlas Nonrigid Registration

Brain anatomy variability is a major problem in quantifying functional images in nuclear medicine, in particular relative to aging and neurodegenerative diseases. The aim of this study was to compare affine and elastic model–based methods for magnetic resonance imaging (MRI) to brain atlas registration and to assess their impact on the quantification of cholinergic neurotransmission. Patients with multiple system atrophy (MSA) and age-matched healthy subjects underwent an MRI and a single-photon emission computed tomographic (SPECT) examination using [123I]-iodobenzovesamicol (IBVM). Both affine and elastic methods were compared to register the subjects' MRI with the Montreal Neurological Institute brain atlas. Performance of the registration accuracy was quantitatively assessed and the impact on the IBVM quantification was studied. For both subject groups, elastic registration achieved better quantitative performance compared to the affine model. For patients suffering from neurogenerative disease, this study demonstrates the importance and relevance of MRI to atlas registration in quantification of neuronal integrity. In this context, in comparison with rigid registrations, an elastic model–based registration provides the best relocation of the brain structures to the atlas for accurately quantifying cholinergic neurotransmission

Theranostics of Primary Prostate Cancer: Beyond PSMA and GRP-R

The imaging of Prostate-Specific Membrane Antigen (PSMA) is now widely used at the initial staging of prostate cancers in patients with a high metastatic risk. However, its ability to detect low-grade tumor lesions is not optimal. Methods: First, we prospectively performed neurotensin receptor-1 (NTS1) IHC in a series of patients receiving both [68Ga]Ga-PSMA-617 and [68Ga]Ga-RM2 before prostatectomy. In this series, PSMA and GRP-R IHC were also available (n = 16). Next, we aimed at confirming the PSMA/GRP-R/NTS1 expression profile by retrospective autoradiography (n = 46) using a specific radiopharmaceuticals study and also aimed to decipher the expression of less-investigated targets such as NTS2, SST2 and CXCR4. Results: In the IHC study, all samples with negative PSMA staining (two patients with ISUP 2 and one with ISUP 3) were strongly positive for NTS1 staining. No samples were negative for all three stains—for PSMA, GRP-R or NTS1. In the autoradiography study, binding of [111In]In-PSMA-617 was high in all ISUP groups. However, some samples did not bind or bound weakly to [111In]In-PSMA-617 (9%). In these cases, binding of [111n]In-JMV 6659 and [111In]In-JMV 7488 towards NTS1 and NTS2 was high. Conclusions: Targeting PSMA and NTS1/NTS2 could allow for the detection of all intraprostatic lesions

Comparison of (68)Ga-PSMA-617 PET/CT and (68)Ga-RM2 PET/CT in patients with localized prostate cancer candidate for radical prostatectomy: a prospective, single arm, single center, phase II study

Considering the wide range of therapeutic options for localized prostate cancer (active surveillance, radiation beam therapy, focal therapy, radical prostatectomy, etc), accurate assessment of the aggressiveness and localization of primary prostate cancer lesion are essential for treatment decision making. National Comprehensive Cancer Network guidelines recognize Prostate-Specific Membrane Antigen (PSMA) Positron Emission Tomography/Computed Tomography (PET/CT) for the initial staging of high risk primary prostate cancer. The Gastrin-Releasing Peptide Receptor (GRP-R) is a neuropeptide receptor over-expressed by low-risk prostate cancer cells. We aim to perform the first prospective head-to-head comparison of PSMA and GRP-R targeted imaging at the initial staging to understand how PSMA-PET and GRP-R-PET could be used or combined in clinical practice Methods: This was a prospective, single-center, diagnostic cross-sectional imaging study using anonymized, masked and independent interpretations of PET/CT paired studies in 22 patients with (68)Ga-PSMA-617 (a radiolabelled PSMA-inhibitor) and (68)Ga-RM2 (a radiolabelled GRP-R-antagonist). We enrolled patients with newly diagnosed, biopsy-proven, prostate cancer. No patient had received neoadjuvant hormone therapy or chemotherapy. All patients underwent extended pelvic lymph node dissection. Histology served as reference. Results: On a lesion-based analysis (including lesions <0.1cc), (68)Ga-PSMA-617 PET/CT detected 74.3% (26/35) of all tumor lesions and (68)Ga-RM2 PET/CT detected 78.1% (25/32; one patient could not be offered (68)Ga-RM2 PET/CT). Paired examinations showed positive uptake with the two tracers in 21/32 lesions (65.6%), negative uptake in 5/32 lesions (15.6%), and discordant uptake in 6/32 lesions (18.8%). Uptake of (68)Ga-PSMA-617 was higher in ISUP ≥ 4 vs ≥ 1 (P < 0.0001); and ISUP ≥ 4 vs 2 (P = 0.002). There were no significant differences in uptake between ISUP scores for (68)Ga-RM2. Median (68)Ga-RM2 SUV(max) was significantly higher than median (68)Ga-PSMA-617 SUV(max) in the ISUP 2 subgroup (P = 0.01). Conclusion: (68)Ga-PSMA-617 PET/CT is useful to depict higher, more clinically significant, ISUP score lesions and (68)Ga-RM2 PET/CT has higher detection rate for low-ISUP tumors. Combining PSMA-PET and GRP-R PET allows to better classify intraprostatic lesions