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Endometriosis is a common gynecologic condition that may be visualized on 18F-FDG PET/CT and mimic lesions of malignancy. We analyzed the interference of known or suspected endometriosis in reporting 18F-FDG PET/CT performed in another indication.The PET/CT images of 18 women with known (n = 15) or suspected (n = 3) endometriosis were analyzed. Based on clinical follow-up and results of other imaging, biopsy, and/or postsurgical histology, the presence of lesions of endometriosis at the time of 18F-FDG PET/CT was confirmed in 13 of 18 patients (72%). The per-patient positivity rate of 18F-FDG PET/CT was 8/18 (44%; 95% confidence interval, 22%-69%). The patient-based detection rate of 18F-FDG PET/CT in patients with confirmed lesions of endometriosis was 8/13 (62%; confidence interval, 32%-86%). On per-lesion/site basis, 18F-FDG PET/CT detected 11 of 20 sites (55%) of endometriosis. The SUVmax of these lesions/sites ranged between 1.8 and 5.3 (median, 3.8). In 9 of 18 patients (50%), a total of 13 non-endometriosis-related lesions/sites were detected by 18F-FDG PET/CT; their SUVmax ranged between 2.7 and 23 (median, 9.4).The interference of known or suspected endometriosis in reporting 18F-FDG PET/CT performed in another indication was limited but possible and should be kept in mind, even in postmenopausal women, as the oldest patient with 18F-FDG-positive endometriosis was aged 63 years. The lesions of endometriosis showed inconstant 18F-FDG uptake with overlap of SUVmax with low-grade malignancies. In our series, the greatest SUVmax value of lesion of endometriosis was 5.3, somewhat higher than the threshold of 4 previously proposed for identification of malignant transformation of endometriosis.

The main purpose of this retrospective study was to determine the diagnostic performance of [68Ga]Ga-DOTA-D-Phe1-Try3-octreotide(DOTA-TOC) positron emission tomography/computed tomography (PET/CT) in patients with well-differentiated colorectal Neuroendocrine Tumours (NETs) originating from the hindgut. The other aims were to assess the impact of the examination on patient management and to analyze the results of 2-[18F]FDG and/or 6-[18F]FDOPA PET/CT when they were performed. [68Ga]Ga-DOTA-TOC PET/CT and clinical data from 30 patients with biopsy-proven well-differentiated NETs originating from the hindgut were retrospectively reviewed and analyzed by comparing the [68Ga]Ga-DOTA-TOC PET/CT findings with pathological and/or follow-up data. We also compared the [68Ga]Ga-DOTA-TOC PET/CT results with 2-[18F]FDG and/or 6-[18F]FDOPA PET/CT results in 6 patients. The impact on management was determined in hindsight by comparing the patient management decided before and after the TEP examination based on data from multidisciplinary team meetings. On a patient basis, [68Ga]Ga-DOTA-TOC PET/CT was accurate in 30 of the 30 examinations. [68Ga]Ga-DOTA-TOC PET/CT correctly identified the primary tumor in all patients with primary tumors not resected before the examination and allowed the detection of unexpected distant metastases in 36% of the patients referred for initial staging. [68Ga]Ga-DOTA-TOC PET/CT findings affected patient management in 57% of cases with generally major intermodality changes. Intraindividual comparison of the results of the different PET radiopharmaceuticals showed a clear superiority of [68Ga]Ga-DOTA-TOC PET/CT considering both the number of lesions and the intensity of uptake. [68Ga]Ga-DOTA-TOC PET/CT is an accurate imaging modality for the assessment of well-differentiated colorectal NETs that highly impact patient management. Thus, we suggest that [68Ga]Ga-DOTA-TOC PET/CT be employed as a first choice for the assessment of these tumors in nuclear medicine.

The production of 51Cr-labelled ethylenediaminetetraacetic acid (51Cr-EDTA), a validated and widely used radio-isotopic tracer for glomerular filtration rate (GFR) measurement in Europe, was recently halted by the manufacturer. Technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA) clearance has so far mostly been restricted to assessment of separate renal function by scintigraphy, but scarcely used and validated for GFR measurement. We compared the performances of 51Cr-EDTA and 99mTc-DTPA for GFR and extracellular fluid measurement. In a multi-centre prospective study, 51Cr-EDTA and 99mTc-DTPA were simultaneously injected into 88 patients, and their urinary and plasma clearances, as well as their volumes of distribution, were measured during seven 30-min periods after a 90-min equilibrium time. Mean age was 52.2 ± 14.5 years, 59% were men. Urinary clearances of 51Cr-EDTA and 99mTc-DTPA were 64.1 ± 27.6 and 66.1 ± 28.0 mL/min, respectively, with a mean bias of 2.00 ± 2.25 mL/min, an accuracy within 10% of 95% [95% CI 91–99], and a coefficient of determination (R2) of 0.994. Plasma clearances of 51Cr-EDTA and 99mTc-DTPA were 66.1 ± 25.8 and 68.1 ± 26.6 mL/min, respectively, with a mean bias of 1.96 ± 3.32 mL/min, an accuracy within 10% of 91% [95% CI 85–97] and a R2 of 0.985. Distribution volumes were 17.3 ± 4.6 L for 51Cr-EDTA and 16.6 ± 4.6 L for 99mTc-DTPA (R2 0.930). The accuracy and precision of 99mTc-DTPA clearance, compared to 51Cr-EDTA clearance, was excellent for both urinary and plasma clearance methods, despite an approximate 2 mL/min overestimation, showing that the tracer is a reliable alternative to 51Cr-EDTA for GFR measurement.

Introduction Peptide-based imaging agents targeting prostate-specific membrane antigen (PSMA) have revolutionized the evaluation of biochemical recurrence of prostate cancer (PCa) but lacks sensitivity at very low serum prostate specific antigen (PSA) levels. Once recurrence is suspected, other positron emission tomography (PET) radiotracers could be of interest to discriminate between local and distant relapse. We studied [18F]fluorodeoxyglucose ([18F]FDG) targeting glucose metabolism, [18F]fluorocholine ([18F]FCH) targeting membrane metabolism and peptide-based imaging agents [68Ga]Ga-PSMA-11, [68Ga]Ga-AMBA, [68Ga]Ga-NODAGA-RGD and [68Ga]Ga-DOTA-NT-20.3 targeting PSMA, gastrin releasing peptide receptor (GRPr), αvβ3 integrin and neurotensin type 1 receptor (NTSR1) respectively, in different PCa tumour models. Methods Mice were xenografted with 22Rv1, an androgen-receptor (AR)-positive, PCa cell line that expresses PSMA and PC3, an AR-negative one that does not express PSMA. PET imaging using the different radiotracers was performed sequentially and the uptake characteristics compared to one other. NTSR1 and PSMA expression levels were analysed in tumours by immunohistochemistry. Results [18F]FDG displayed low but sufficient uptake to visualize PC3 and 22Rv1 derived tumours. We also observed a low efficacy of [18F]FCH PET imaging and a low [68Ga]Ga-NODAGA-RGD tumour uptake in those tumours. As expected, an elevated tumour uptake was obtained for [68Ga]Ga-PSMA-11 in 22Rv1 derived tumour although no uptake was measured in the androgen independent cell line PC3, derived from a bone metastasis of a high-grade PCa. Moreover, in PC3 cell line, we obtained good tumour uptake, high tumour-to-background contrast using [68Ga]Ga-AMBA and [68Ga]Ga-DOTA-NT-20.3. Immunohistochemistry analysis confirmed high NTSR1 expression in PC3 derived tumours and conversely high PSMA expression in 22Rv1 derived tumours. Conclusion PET imaging using [68Ga]Ga-AMBA and [68Ga]Ga-DOTA-NT-20.3 demonstrates that GRPr and NTSR1 could represent viable alternative targets for diagnostic or therapeutic applications in PCa with limited PSMA expression levels. More preclinical and clinical studies will follow to explore this potential. Advances in knowledge and implications for patient Peptide-based imaging agents targeting PSMA represent a major progress in the evaluation of biochemical recurrence of PCa but sometimes yield false negative results in some lesions. Continuing efforts have thus been made to evaluate other radiotracers. Our preclinical results suggest that [68Ga]labelled bombesin and neurotensin analogues could serve as alternative PET radiopharmaceuticals for diagnostic or therapy in cases of PSMA-negative PCa.

PURPOSE 18F-labeled fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET-CT) data in HIV-associated Hodgkin lymphoma (HIV-HL) are scarcely reported. In addition to the description of the characteristics of both baseline and interim 18F-FDG PET-CT examinations (PET1 and iPET, respectively), the aim of this study was to assess the prognostic value of PET1 and previously identified clinical parameters in this population. PATIENTS AND METHODS PET1 of 109 patients with HIV-HL, treated with doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy regimen since 2007, and 104 iPET were centrally reviewed. All the patients were enrolled in an ongoing prospective single-center cohort of HIV-associated lymphoma. RESULTS Most patients had a disseminated disease according to the Ann Arbor classification (30% stage III and 43% stage IV), with especially bone marrow and liver as extranodal localizations. After a median follow-up of 6.7 years, 12 patients relapsed (11%) and 13 died (12%). Five-year progression-free survival (PFS) was 75.1%, and 5-year overall survival was 86.1%. Median total metabolic tumor volume (TMTV) was 121.4 cm3. The optimal TMTV cutoff identified for prognostic analysis was 527 cm3, with a 2-year PFS of 71% in the 20 patients with TMTV > 527 cm3, compared with 91% in the 89 patients with TMTV ≤ 527 cm3 ( P = .004). On multivariate analysis, a high TMTV was the only parameter independently associated with PFS. CONCLUSION In this large series of HIV-HL patients with a homogeneous management, high TMTV on PET1 examination was associated with a poor prognosis.

The aim of this study was to assess the performance of 68Ga-DOTATOC PET/CT in the detection and extension of insulinomas according to 3 different contexts: sporadic benign, sporadic metastatic, and multiple endocrine neoplasia type 1 (MEN1).The data of 71 adult patients who underwent 68Ga-DOTATOC PET/CT for suspected or confirmed sporadic insulinoma, suspicion of insulinoma in the context of MEN1, follow-up of metastatic insulinoma, or suspicion of recurrence of insulinoma were retrospectively analyzed. Pathological examination or strong clinical and biological findings were used as standards of truth.For the assessment of a confirmed sporadic insulinoma in 17 patients, the sensitivity of SR-PET was 75%, including 2 patients for whom metastatic lesions had been revealed by SR-PET. For 35 patients with a suspicion of insulinoma, the sensitivity was 39%. In 10 patients followed up for metastatic insulinoma, the sensitivity was 100%. For 5 patients with a history of MEN1, interpretation of SR-PET was difficult, as 3 of them presented with multiple pancreatic uptake foci. The global sensitivity of SR-PET in all insulinomas excluding those with a MEN1 story was 64% (100% for metastatic insulinomas, 62% for benign insulinomas), with a specificity of 89%.68Ga-DOTATOC PET/CT is a useful examination tool for the assessment of insulinomas in selected contexts, with very high performance for the detection and extension workup of metastatic insulinomas and high specificity for the detection of sporadic benign insulinomas. The examination should be completed with GLP-1 receptor PET when it is negative or in a MEN1 context.

International audience; Biochemical recurrence after primary treatment in prostate cancer is not uncommon. A rising serum prostate-specific antigen level represents a first sign of disease relapse. At this time of low disease burden, imaging and particularly magnetic resonance imaging and positron emission tomography/computed tomography (PET/CT) are essential to determine the localization of the recurrence, which may be local, in lymph nodes, and/or metastatic. Imaging results allow best determine modalities of salvage treatment, which can be local by using radiotherapy or other focal treatments or systemic using hormonotherapy. Current evidence suggests that multiparametric magnetic resonance imaging, PET/CT with prostate specific membrane antigen and lympho-magnetic resonance imaging are effective and complementary to detect local recurrences and distant metastases.

180 Background: Cabazitaxel and Lu-PSMA both improved survival in patients with mCRPC after docetaxel and an androgen receptor pathway inhibitor (ARPI), but there is limited data regarding Lu-PSMA activity after cabazitaxel. We aimed at assessing activity of Lu-PSMA and determinants of outcomes in this setting. Methods: Consecutive mCRPC patients from 6 European centers treated with Lu-PSMA after cabazitaxel were included in this retrospective study. Endpoints included radiographic progression-free survival (rPFS), time to PSA progression (PSA-TTP), PSA decline, objective response, overall survival, and safety. Results: Of 101 patients included (median age 67y), 64% had ISUP grade 4-5 disease; 71% had bone +/- nodal (LN) metastases, 22% visceral metastases, 7% LN only. All patients and 92% had received previous docetaxel and a prior ARPI (≥ 2 in 47%) before cabazitaxel respectively. Patients had received a median number of 6 cabazitaxel cycles (range 1-26). DNA damage repair alterations (DDR) were found in 11/48 (23%) patients with available testing. Patients received a median number of 3 Lu-PSMA cycles (range 1-14). With a median follow-up of 5.7 months, the median rPFS from Lu-PSMA initiation was 4.3 months (m, 95%CI 3.2-5.7) and median PSA-TTP was 3.5 m (95%CI 3.0-4.5). Overall, 44 patients (44%) experienced a PSA decline ≥ 50% (PSA50), 54 (53%) ≥ 30% (PSA30), and 67 (66%) any PSA decline. Objective response rate was 34%. Baseline characteristics associated with shorter rPFS on Lu-PSMA included ISUP grade 4-5 disease (median rPFS of 3.5 vs. 7.2m, p=0.02) and a time to castration resistance < 12 months (3.1m vs. 4.5m, p=0.04). Patients with LN only had longer rPFS compared to those with bone and visceral metastases (median NR vs. 3.6 and 3.7m, respectively, p=0.02). There was no association between activity of Lu-PSMA and DNA damage repair alterations, duration of previous cabazitaxel therapy, and number of previous ARPI. During Lu-PSMA, a profound PSA decline was associated with longer rPFS: patients achieving PSA50, PSA30 or any PSA decline had respective median rPFS rates of 9.0, 8.3 and 6.2 months, while those who did not experience any PSA decline had a median rPFS of only 2.6 months. Conclusions: Lu-PSMA demonstrated substantial PSA decline but limited duration of response after cabazitaxel in a real-life setting. Adverse baseline characteristics and absence of PSA decline may help early identification of poor responders.

IgG4-Related Disease (IgG4-RD) results from tissue infiltration by IgG4-expressing plasma cells and lymphocytes, leading to fibrosis and organomegaly. Clinical presentation is remarkably variable according to organ involvement, and high IgG4 serum concentration, initially considered a diagnostic hallmark of IgG4-RD, tends to be forgone as an indispensable criterion for its diagnosis; it can indeed be absent in some patients, highlighting the diversity of presentation of this dysimmune condition. Nevertheless, elevation of IgG4 serum concentration in suggestive settings remains an argument in favour of IgG4-RD, and while other IgG subclasses can be elevated, this biological feature lacks any diagnostic value. We retrospectively studied 9 patients (5 females, 4 males, 31-81 years old) for whom a diagnosis of IgG4-RD had been considered, based on clinical, imaging or histological criteria, but appeared to display abnormally high serum IgG2 while IgG4 levels were normal. Increased serum IgG1 in one case and increased IgG3 in another one were also noticed. Immunohistochemical analyses of intracellular immunoglobulins could be performed on tissue lymph node biopsies from 2 patients, which demonstrated strong infiltration with IgG2-expressing plasma cells. Thus, overexpression of IgG2 subclass may highlight cases of dysimmune disorders resembling IgG4-RD, although the disease trigger might be different, notably infectious. We suggest measuring all serum IgG subclass levels in patients with features consistent with IgG4-RD.

Background The incidence of pregnancy-associated cancers has been increasing for decades. (18F)-FDG Positron Emission Tomography (PET)/Computed Tomography (CT) imaging has become a golden standard in the staging of many malignant diseases. The aims of the current study were to evaluate the feasibility, safety and impact of (18F)-FDG PET/CT performed during pregnancy. Material and methods A retrospective analysis from the prospective database of the Cancer Associe a La Grossesse (CALG) network (Tenon Hospital, France) including patients who underwent (18F)-FDG PET/CT during their pregnancy between 2015 and 2020. Results Of the 536 patients for whom advice from the CALG network was requested during the study period, 359 were diagnosed with cancer during pregnancy. Study population was composed of 63 (17.5%) patients who underwent (18F)-FDG PET/CT. Most cancers were diagnosed during the second trimester. Seventy-five percent were diagnosed with breast cancer, mostly locally advanced invasive ductal carcinomas. Median term of pregnancy at PET/CT was 24.8 weeks of gestation. Twelve (19%), 24 (38.1%) and 22 (34.9%) patients underwent the exam during the 1st, 2nd and 3rd trimester, respectively. (18F)-FDG PET/CT resulted in stage modification for 38 (60.3%) of the patients (28 with more extensive lymph node involvement and 10 with metastatic disease) with subsequently/accordingly modified first-line medical treatment. Fifty patients gave birth to healthy newborns. Two patients had a medical termination of pregnancy, five had a medical abortion, one neonatal death occurred in a patient with severe preeclampsia (unrelated to (18F)-FDG PET/CT). The data of 46 children were available at 6 months, 29 at 12 months, and 15 at 24 months. No cases of mental retardation, childhood cancer, or malformation were reported within 2 years. Conclusion (18F)-FDG PET/CT has a major impact on the management of pregnancy-associated cancers and does not appear to cause fetal side effects suggesting that the exam is feasible during pregnancy as maternal benefits outweigh fetal risks.

Thymic neuro endocrine tumor (tNET) are extremely rare malignancies with poor prognosis, requiring investigation of novel therapeutic approaches. 177Lu-DOTATATE is a successful systemic treatment modality in patients with metastatic gastroenteropancreatic but it role in tNET is not yet well established. Here we report a case of a 39-year-old man with refractory bone marrow infiltration of a tNET, treated by 4 cycles of peptide receptor radionuclide therapy (PRRT) with 177Lu DOTATATE. Since the first cycle, clinical symptoms were substantially decreased, without any severe subacute haematological toxicity. Three months after the end of PRRT, both 68Ga-DOTATOC and 18F-FDG PET confirmed a partial response, already suggested by 177Lu-DOTATATE treatment scan with a significant decrease of the bone marrow uptake between the first and fourth cycle. This report highlights that PRRT could be an effective therapeutic option for advanced bone metastatic disease tNET, with the significant benefit of alleviation of bone pain and radiologic response, without severe or irreversible haematotoxicity.

Paraneoplastic Cushing’s syndrome (PCS) is frequently caused by neuroendocrine tumours (NETs). Approximately 20% of tumours are still occult years later. Gallium-68 somatostatin receptor-PET/CT is promising for the detection of the causal primary NET, but its role in case of recurrent PCS is rarely reported. We report our experience with DOTATOC PET/CT in localising the causal NET in cases of initial but also recurrent PCS, and its clinical impact. A retrospective review of all DOTATOC PET/CTs performed in consecutive patients referred for PCS to our centre, between January 2011 and June 2017, was done. Nineteen patients underwent 26 PET/CTs, 13 for detection of a primary NET, seven for persistent or recurrent PCS after resection, and six for surveillance after resection of NETs previously detected on a DOTATOC PET/CT in our centre. Among the 13 PET/CTs performed to search for primary NET, five were positive: four carcinoid lung tumours were confirmed after resection and one lung focus was not confirmed since surgery would have carried a high risk. Clinical impact was 23% (3/13). Among the seven PET/CTs performed for persistent or recurrent PCS, six were true-positive, with confirmation of metastatic lymph nodes after resection. Clinical impact was 57% (4/7). All PET/CTs performed for surveillance were true-negative. DOTATOC PET/CT seems to be a valuable tool for detection of the NET responsible for persistent or recurrent PCS after surgery. In this context, DOTATOC PET/CT was more effective than for the detection of the causal tumour in initial PCS.

International audience; Rationale: Peptide receptor radionuclide therapy (PRRT) with 177 Lu-DOTATATE (oxodotreotide) results in external radiation exposure from the patient. In the PREELU observational prospective study, we determined the equivalent dose rate at 1 m of the patient (EDR-1m) for a period following PRRT. The main objective was to predict which patients could be discharged from the hospital at approximately 3 h after the administration of 177 Lu-DOTATATE, i.e. at the end of the infusion of amino-acids according to our PRRT protocol. As presenting no undue risk of radiation exposure for the public, those patients could be treated as outpatients or day patients, rather than inpatients. Methods: We sequentially measured EDR-1m facing the sternum and then the pelvis during 50 PRRT in 24 patients with metastatic neuroendocrine tumours, each 30 minutes after ending administration of Lutathera, over at least 180 minutes. Results: 180 minutes after the administration of ca. 7400 MBq of Lutathera, EDR-1m was 96 mL/min/1.73m 2 , the EDR-1m was most likely (predictive value=90%) to drop below 25 µSv/h within 180 minutes after the administration of Lutathera. In 16 patients who benefited from several PRRT cycles, the creatinine clearance did not decrease significantly from one cycle to the next, probably due to the kidney protection by the amino-acid infusion. The patients whose EDR-1m dropped below 25 µSv/h at 180 minutes during their first PRRT cycle were unlikely (predictive value= 88%) to decease during the following two years. Conclusion: All patients could have been discharged 3 h after administration according to the criterion EDR-1m

Hodgkin lymphoma (HL) is the most common cancer in adolescence and represents 15% of all cases of cancer in children and adolescents. In three decades, HL has become a highly curable lymphoid malignancy with an expected survival rate at ten years of around 90–93%. Further refinements of treatment strategy are needed in order to improve treatment results in relapsed and refractory patients and to reduce long-term morbidity of therapy, mainly secondary malignancies, cardiovascular early morbidity, and impaired fertility. Progress in imaging definition of involvement based on fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) and response-adapted strategy based on FDG-PET/CT intermediate evaluation has led to a reduction of radiotherapy. Procarbazine-free chemotherapy regimens with moderate anthracyclin dose will further reduce the risk of treatment’s sequelae. Recent advances in the understanding of the biology of HL have demonstrated, with promising results, the link between immune system control and Hodgkin lymphoma pathogenesis, opening the road to new treatments in relapsed and refractory patients based on targeted monoclonal antibodies.

The production ofIn a multi-centre prospective study,Mean age was 52.2 ± 14.5 years, 59% were men. Urinary clearances ofThe accuracy and precision of

To develop criteria to improve discrimination between vertebral metastases from neuroendocrine tumours (NETs) and benign bone lesions on PET combined with CT using DOTA-D-Phe1-Tyr3-octreotide labelled with gallium-68 (68Ga-DOTA-TOC). In 535 NET patients, 68Ga-DOTA-TOC PET/CT examinations were reviewed retrospectively for vertebral CT lesions and/or PET foci. For each vertebral PET abnormality, appearance on CT, biological volume (BV), standardized uptake value (SUVmax) and ratios to those of reference organs were determined. All vertebral abnormalities were characterized as a metastasis, a typical vertebral haemangioma (VH) or other benign lesion. In 79 patients (14.8 %), we found 107 metastases, 34 VHs and 31 other benign lesions in the spine. The optimal cut-off values to differentiate metastases from benign lesions were BV ≥0.72 cm3, SUVmax ≥2, SUVmax ratio to a reference vertebra ≥2.1, to liver ≥0.28 and to spleen ≥0.14. They corresponded to lesion-based 68Ga-DOTA-TOC PET/CT sensitivity of 87 %, 98 %, 97 %, 99 % and 94 %, and specificity of 55 %, 100 %, 90 %, 97 %, 100 %, respectively. The high sensitivity of 68Ga-DOTA-TOC-PET/CT in detecting NET vertebral metastases was confirmed; this study showed that specificity could be improved by combining CT features and quantifying 68Ga-DOTA-TOC uptake. • Bone metastases in neuroendocrine tumours correlate with prognosis. • Benign bone lesions may mimic metastases on 68 Ga-DOTA-TOC PET/CT imaging. • The specific polka-dot CT pattern may be missing in some vertebral haemangiomas. • Lesion atypical for haemangiomas can be better characterized by quantifying 68 Ga-DOTA-TOC uptake.

Oncogenic osteomalacia is an endocrine disorder induced by small benign tumours (TIO) producing excessive fibroblast growth factor-23 (FGF23). The only way of curing oncogenic osteomalacia is surgical resection of the culprit TIO, which is extremely difficult to detect using conventional imaging modalities due to its small size and variable location in the body. Since TIO frequently overexpress somatostatin receptors, a clinical utility of SPECT or PET with radiolabelled somatostatin analogues has been reported. Among them, 68Ga-DOTA-TOC has recently been granted a marketing authorization, facilitating its routine application. We report here the results of the first series evaluating the diagnostic performance of 68Ga-DOTA-TOC PET/CT in detecting TIO and its impact on patient management. 68Ga-DOTA-TOC PET/CT and clinical and imaging data from 15 patients with clinical and biochemical signs of oncogenic osteomalacia were retrospectively reviewed. The 68Ga-DOTA-TOC PET/CT findings were compared with the results of post-surgical pathology and clinical and biochemical follow-up. 68Ga-DOTA-TOC PET/CT resulted in the detection of one focus suspicious for TIO in nine of 15 patients (60%), and a tumour was surgically removed in eight. Post-operative pathology confirmed a TIO in those eight patients whose symptoms diminished promptly and biochemical anomalies resolved. 68Ga-DOTA-TOC PET/CT sensitivity, specificity and accuracy were 73%, 67% and 71%, respectively. 68Ga-DOTA-TOC PET/CT findings affected patient management in 67% of cases. In particular, 68Ga-DOTA-TOC PET/CT was able to detect the TIO with a negative or a false-positive result of a previous 111In-pentetreotide SPECT/CT in 5/8 patients (63%) or a previous FDG PET/CT in 7/11 patients (64%). No close relationship was found between the positivity of 68Ga-DOTA-TOC PET/CT and the serum level of a biochemical marker. However, a true-positive result of 68Ga-DOTA-TOC PET/CT was obtained in only one patient with a non-elevated serum level of FGF23. 68Ga-DOTA-TOC PET/CT is an accurate imaging modality in the detection of TIO; in particular, it is worthwhile after failure of somatostatin receptor SPECT(/CT) or FDG PET/CT.

A 47-year-old woman with a history of surgically treated abdominal paraganglioma and left thigh melanoma underwent an F-FDOPA PET/CT for suspected locoregional recurrence of paraganglioma. F-FDOPA PET/CT disconfirmed this recurrence but revealed 2 FDOPA-avid left inguinal lymph nodes, confirmed on a subsequent F-FDG PET/CT. Excision and pathology characterized these lymph nodes as melanoma metastases. F-FDOPA PET/CT is a widely used and valuable tool in the assessment of paraganglioma, both for staging and recurrence detection. Uptake of FDOPA has only rarely been documented in metastatic melanoma that could be a pitfall for detecting neuroendocrine tumors.

We aimed to evaluate the impact of prostate-specific membrane antigen ligand labelled with gallium-68 (PSMA-11) PET/CT in restaging patients with castration-resistant nonmetastatic prostate cancer (PCa). Thirty patients were included. At least one malignant focus was found in 27/30 patients (90%). The PSMA-11 PET/CT positivity rate in patients whose prostate-specific antigen serum level (PSA) was greater than 2 ng/ml was 100% (20/20), significantly superior to that of patients whose PSA was less than 2 ng/ml (7/10 = 70%). Six patients (20%) were categorized as oligometastatic (≤3 metastatic foci). Based on the 17 patients for whom a standard of truth was feasible, the overall sensitivity and specificity of PSMA-11 PET/CT in detecting residual disease in castration-resistant PCa patients were 87% and 100% respectively. PSMA-11 PET/CT impacted patients’ disease management in 70% of cases, 60% of case when PSA was less than 2 ng/ml. This management was considered as adequate in 91% of patients. PSMA-11 PET/CT appeared to be effective in restaging patients with castration-resistant nonmetastatic PCa. PSMA-11 PET/CT should be considered as a replacement for bone scans under these conditions.

The use of PET/CT with prostate-specific membrane antigen radioligands for staging prostate cancer patients presenting a biochemical recurrence is increasing. As a consequence, the number of reports of diagnostic pitfall of this imaging modality is also increasing. A 75-year-old man referred for a second episode of biochemical recurrence of prostate cancer presented an isolated intense prostate-specific membrane antigen-11 uptake from a right lung abnormality. This abnormality was suggestive of pulmonary vein varix on contrast-enhanced lung CT. The uptake remained stable 1 month after starting androgen deprivation therapy, which confirmed the diagnostic of pulmonary vein varix.

Thymic neuro endocrine tumor (tNET) are extremely rare malignancies with poor prognosis, requiring investigation of novel therapeutic approaches.

Resume L’antigene membranaire prostatique specifique (PSMA) est une proteine membranaire de type II surexprimee par le tissu prostatique cancereux, particulierement dans les cancers de la prostate de haut grade, dans les maladies metastatiques, comme un effet des traitements de deprivation androgenique et au stade de resistance a la castration (CPRC). Les recentes publications portant sur la radiotherapie interne vectorisee (RIV) par ligands du PSMA marques avec du lutetium-177 (177Lu) chez les patients au stade CPRC la presente comme une alternative therapeutique interessante en 3e ligne de traitement apres anti-androgenes de seconde generation et chimiotherapie par taxane. Nous presentons ici le cas d’un patient CPRC en echec de traitement par deprivation androgenique et chimiotherapie, traite par RIV iterative utilisant le ligand du PSMA-617 marque par du 177Lu. Ce cas illustre, d’une part, l’efficacite clinicobiologique de la RIV par 177Lu-PSMA et, d’autre part, la fragilite des patients deja a un stade avance de leur maladie et pouvant presenter un evenement intercurrent grave sans que celui-ci soit necessairement lie au traitement en cours. Nous presentons ensuite une courte revue de la litterature sur ce sujet, avec presentation des resultats sur l’efficacite et la tolerance publies de la RIV par 177Lu-PSMA chez les patients CPRC.

Resume De par son approche fonctionnelle et la bonne resolution des images obtenues, la TEP fusionnee a la TDM ou a l’IRM apparait comme la modalite d’imagerie actuellement la plus prometteuse pour deceler et denombrer les metastases des cancers. Lorsque le nombre de metastases est limite, l’extension est dite oligometastatique, ouvrant la voie a une therapie ciblee (en particulier radiotherapie stereotaxique) sur les quelques lesions secondaires. Cette approche s’est particulierement repandue dans le cancer de la prostate (CP). L’imagerie TEP/TDM a un vaste potentiel pour la caracterisation du CP comme oligometastatique, d’une part, en decelant les metastases a un stade precoce et, d’autre part, en evitant d’appliquer a des CP qui sont en fait polymetastatiques une prise en charge de type oligometastatique qui serait inefficace et retarderait la mise en œuvre de la therapie appropriee. Cet article illustre cette application nouvelle de la TEP realisee a l’aide de divers traceurs TEP appropries a l’imagerie du CP, disponibles en routine comme le fluorure (18F) de sodium, la fluorocholine (18F), la fluciclovine (18F) ou qui n’ont pas encore d’AMM comme les ligands de l’antigene specifique de la prostate marques au 68Ga ou au 18F.

Introduction L’insulinome est la plus frequente des tumeurs neuroendocrines (TNE) fonctionnelles du pancreas, la plupart du temps benigne (sporadique ou au sein d’une neoplasie endocrinienne multiple ou NEM). Son traitement curatif est l’exerese, qui necessite une localisation preoperatoire precise. TDM, IRM et echo-endoscopie ne permettent pas toujours de localiser la lesion et la TEP/TDM au 68Ga-DOTATOC est negative dans environ 50 % des cas du fait d’une densite insuffisante de recepteurs de la somatostatine type-2 comparativement aux autres TNE pancreatiques. L’exendine-4 est un ligand des recepteurs du GLP1, surexprimes dans la quasi-totalite des insulinomes, sauf les insulinomes malins. Suite a notre participation a une etude europeenne multicentrique (GLPExend) evaluant les performances de ce radiotraceur marque au 68Ga, nous avons pu poursuivre cet examen par ATU nominatives chez des patients atteints d’hypoglycemie par hyperinsulinisme endogene prouve, mais sans lesion localisable formellement en imagerie conventionnelle. Materiel et methodes Entre janvier 2020 et fevrier 2021, 17 patients ont realise l’examen (âge moyen 41,8 ans [8–72]), dont 3 NEM1 et 1 insulinome malin metastatique, apres injection IV d’une activite de 119 MBq en moyenne et acquisition de la TEP/TDM (Siemens, Biograph) 60 min apres. Resultats 11/17 (65 %) examens etaient positifs, detectant 12 foyers evocateurs, 3 (18 %) douteux, 3 (18 %) sans anomalie. La fixation des lesions detectees etait intense (moyenne SUVmax 29,4 [3,6–155]), bien davantage que le reste du parenchyme pancreatique (rapport moyen de 4,5 entre la lesion hyperfixante et le pancreas sain, avec pour le parenchyme pancreatique sain un SUVmax moyen de 8,3), sauf dans le cas de la patiente adressee pour insulinome malin (tres discrete hyperfixation des lesions, bien mieux visualisees en TEP/TDM au DOTATOC). La confirmation histologique d’un foyer comme insulinome (sur biopsie ou piece chirurgicale apres exerese) a ete obtenue chez 8 des patients dont l’examen etait positif. Pour les 3 autres examens positifs, la confirmation n’est pas encore disponible. Dans le cas des examens negatifs ou douteux, aucune lesion susceptible d’etre responsable du tableau clinique n’a pu etre localisee durant le suivi. Conclusion La TEP/TDM au 68Ga-exendine-4 s’est revelee primordiale dans la detection d’insulinomes jusque-la occultes, avec un fort contraste par rapport au reste du pancreas, sauf en cas d’insulinome malin.

Neuroendocrine tumours (NET) are heterogeneous and frequently spread over the body, making their imaging difficult. With this aim, nuclear medicine imaging, using PET or SPECT with different tracers, has been proposed for decades, but there is currently no consensus on the most appropriate technique, even when only considering gastrointestinal NET. The case is presented of a 67year old woman with a well differentiated NET of the ileum with suspected recurrence, which was not detected by any imaging technique except 18F-FDOPA PET/CT. Subsequent follow up showed disease progression, which confirmed the true positivity of 18F-FDOPA. Using this case, we discuss and compare different radiotracers for the diagnosis of gastrointestinal NET, focusing on those embryologically originating from the mid-gut.

Neuroendocrine tumours (NET) are heterogeneous and frequently spread over the body, making their imaging difficult. With this aim, nuclear medicine imaging, using PET or SPECT with different tracers, has been proposed for decades, but there is currently no consensus on the most appropriate technique, even when only considering gastrointestinal NET. The case is presented of a 67year old woman with a well differentiated NET of the ileum with suspected recurrence, which was not detected by any imaging technique except 18F-FDOPA PET/CT. Subsequent follow up showed disease progression, which confirmed the true positivity of 18F-FDOPA. Using this case, we discuss and compare different radiotracers for the diagnosis of gastrointestinal NET, focusing on those embryologically originating from the mid-gut.

Background/Aim: Somatostatine receptors subtype 2 (SSTR2) are regarded as a potential target in neuroblastoma (NB) for imaging and promising therapeutic approaches. The purpose of this study was to evaluate and compare the SSTR2 status by 68Ga-[tetraxetan-D-Phe1, Tyr3]-octreotide (68Ga-DOTATOC) positron-emission tomography (PET) and the tumour metabolic activity by 18F-fluorodeoxyglucose (FDG) PET in different experimental models of NB. Materials and Methods: Three cell lines of human NB with different levels of expression of SSTR2 were grafted into nude mice. Animals were imaged with FDG and 68Ga-DOTATOC and the maximum standardized uptake value (SUVmax) was determined to quantify tracer uptake. Ex vivo biodistribution of 68Ga-DOTATOC and immunohistochemical analysis of NB xenografts were performed. Results: Compared with FDG, the SUVmax of 68Ga-DOTATOC uptake by the tumour was lower but the ratio to background was higher; there was a strong positive correlation between SUVmax values observed with the two tracers (r2=0.65). Sorting the cell lines according to uptake of FDG or 68Ga-DOTATOC, injected activity per gram of tissue, Ki67 index or expression of SSTR2 assessed visually led to the same classification. Conclusion: 68Ga-DOTATOC allows preclinical imaging of NB according to the intensity of the expression of SSTR2. In contrast with what has been reported for neuroendocrine tumours, in this NB model, the 68Ga-DOTATOC uptake was positively correlated with FDG uptake and with Ki67 index, usual markers of tumour aggressiveness. If confirmed in humans, this result would favour a theranostic application of 68Ga-DOTATOC in NB, even in advanced stages.

Introduction Le 177Lu-Dotatate (Lutathera®) est utilise pour la radiotherapie interne vectorisee (RIV) des tumeurs neuroendocrines gastro-entero-pancreatiques (TNE-GEP) disseminees et inoperables. La duree d’hospitalisation des patients est un sujet de controverse en France, liee en particulier a la radio-exposition de l’entourage du fait de l’emission gamma du 177Lu. Nous avons analyse la decroissance du debit de dose externe a 1 m des patients traites par Lutathera® en chambre de RIV, en relation avec les donnees pre-therapeutiques. Methodes Etude bi-centrique prospective observationnelle durant 2 ans chez des patients atteints de TNE-GEP traites par Lutathera®. La calibration croisee des detecteurs a ete prealablement effectuee. Ont ete recueillis le consentement du patient et ses donnees cliniques et para-cliniques, en particulier la TEP/TDM au 68Ga-DOTATOC ou la scintigraphie des recepteurs de la somatostatine au 111In-pentetreotide. Apres la fin de l’administration du Lutathera sur 30 min, des mesures repetees du debit de dose a 1 m ont ete effectuees jusqu’a 24 h, au niveau du thorax et du pelvis. L’analyse multivariee des donnees cliniques et para-cliniques du patient a ete realisee pour rechercher une relation avec la decroissance du debit de dose. Resultats De mai 2016 a septembre 2018, 50 series de mesures ont ete realisees chez 24 patients : 8 patients a HUEP (hopital universitaire de l’Est Parisien) et 16 patients a l’institut Gustave-Roussy. Le debit de dose a 1 m mesure sur le thorax et le pelvis a la fin de la procedure standard de surveillance (4 h en general) a ete Conclusion Apres la fin de l’administration du Lutathera®, 4 heures suffisent en general pour assurer la radioprotection de l’entourage. Chez certains patients (insuffisance renale, forte masse tumorale), les donnees pre-therapeutiques font prevoir une duree d’hospitalisation prolongee si on fixe le seuil de debit de dose a 25 μSv/h.

A 67-year-old woman was referred for staging of an insulinoma. CT has shown a pancreatic tumor, a portal thrombus, and an ovarian mass presumed not to be related with the insulinoma. These three lesions were highly positive on Ga DOTATOC PET/CT, leading to the hypothesis of a malignant insulinoma with neoplastic vein thrombus and ovarian metastasis, which was subsequently confirmed histologically. Despite severe hypoglycemia preventing fasting, F-FDG PET/CT was informative, showing significant uptake by the thrombus, which corresponded to the most aggressive lesion (Ki67 of 3.5% for the primary pancreatic tumor and 19.6% for the thrombus).

Introduction AMBA is a bombesin analogue that binds to GRPr. In a mouse model of estrogen-dependent human breast cancer, we tested whether 68 Ga-AMBA can be used for PET detection of GRPr-expressing tumors and could be more accurate than 18 F-FDG to monitor tumor response to hormone therapy. Methods The radiolabeling of 68 Ga-AMBA was automated using a R&D Synchrom module. ZR75-1, a breast cancer cell line, was xenografted in nude mice. 68 Ga-AMBA tumor uptake was compared with that of 18 F-FDG before and after treatment with tamoxifen. Results AMBA was 68 Ga-radiolabelled in 30 min with 95.3% yield and purity ≥ 98%. Prior to treatment, 68 Ga-AMBA was highly concentrated into tumors (tumor to non-tumor ratio = 2.4 vs. 1.3 with 18 F-FDG). With tamoxifen treatment (n = 6) 68 Ga-AMBA uptake plateaued after 1 week and decreased after 2 weeks, with a significant reduction compared to controls (n = 4). In contrast the effect of tamoxifen treatment could not be appreciated using 18 F-FDG. Conclusions 68 Ga-AMBA appeared better than 18 F-FDG to visualize and monitor the response to hormone treatment in this breast cancer model.

We report 2 cases of young patients referred for FDG PET/CT for peripheral lymphadenopathy and moderate fever associated with pericarditis in 1 patient and glomerulonephritis in the other patient. FDG PET/CT showed a very similar appearance in these 2 patients, with highly avid lymph nodes with axillary predominance and diffuse FDG uptake in spleen and bone marrow. Systemic lupus erythematosus with an unusual presentation of generalized lymphadenopathy was diagnosed in both patients. This FDG distribution pattern should be kept in mind when PET is performed for etiological investigation of fever of unknown origin.

To develop criteria to improve discrimination between vertebral metastases from neuroendocrine tumours (NETs) and benign bone lesions on PET combined with CT using DOTA-D-PheIn 535 NET patients,In 79 patients (14.8 %), we found 107 metastases, 34 VHs and 31 other benign lesions in the spine. The optimal cut-off values to differentiate metastases from benign lesions were BV ≥0.72 cmThe high sensitivity of• Bone metastases in neuroendocrine tumours correlate with prognosis. • Benign bone lesions may mimic metastases on

IF 2.755; International audience; Two hundred and ten nuclear medicine physicians, radiologists, and hematologists from 26 countries attended the 6th International Workshop on Positron Emission Tomography (PET) in Lymphoma and Myeloma held in Menton, France, in September 2016. The meeting was under the auspices of the European Lymphoma Institute (ELI), the European Association of Nuclear Medicine (EANM) the Lymphoma Study Association (LYSA), the Italian Foundation on Lymphoma (FIL) and the Carnot Institute for Lymphoma (CALYM). Forty scientific posters were presented. For the first time, specialists in the field of multiple myeloma (MM) were involved in the expert session. The aim was to establish from the experience of Italian and French studies new guidelines of FDG-PET/CT reporting for myeloma staging and restaging. The meeting dedicated an entire session to MM imaging followed by a session on the role of PET in Peripheral T cell Lymphoma. An entire session addressed the issues of Deauville scale particularly for end treatment assessment and the challenging consequences of immunomodulatory treatments on PET reporting. A specific session presented the potential role of baseline metabolic tumor measurement to predict outcome and identify different risk categories and the main results obtained in different lymphoma entities were described. Whether it could replace clinical staging has been extensively discussed. The more recent results obtained in the H10 trial have been presented and compared to the published data in early stage Hodgkin lymphoma. Finally, the ongoing studies using PET for guiding therapeutic strategies have been reported by the various lymphoma cooperative groups that participated to the meeting.

Resume Cet article fait le point sur le role de la TEP/TDM au FDG dans les tumeurs de l’intestin grele, tumeurs neuro-endocrines exclues. Les adenocarcinomes, les lymphomes et les sarcomes (dont les tumeurs stromales ou GIST) sont etudies. Il n’existe pas de recommandation specifique de la TEP/TDM FDG pour les adenocarcinomes primitifs du grele, extremement rares en comparaison des adenocarcinomes colorectaux. Neanmoins, l’utilite de l’examen a ete rapportee dans quelques cas cliniques pour leur detection et stadification en particulier chez les patients a risque de developper ce cancer (la maladie de Crohn etant le facteur de risque le plus important). Les lymphomes primitifs du grele sont egalement tres rares. Ce sont toujours des lymphomes non hodgkiniens (LNH) pour lesquels le role de la TEP FDG est reconnu pour les types histologiques suivants : lymphome folliculaire, lymphome B a grandes cellules, lymphome de Burkitt. Les tumeurs stromales correspondent aux sarcomes les plus frequents. Elles concernent plus rarement le grele que l’estomac. Le role de la TEP/TDM FDG est bien etabli pour evaluer l’extension de la maladie et pour suivre l’efficacite du traitement par les antityrosines kinases, l’evaluation de la reponse etant possible en TEP des les premiers jours du traitement. La TEP FDG pour l’evaluation de la reponse therapeutique est d’autant plus utile que la reponse radiologique est difficile a apprecier, devant se baser non sur un critere de diminution de taille mais sur un critere de diminution de densite et de prise de contraste des lesions.

Resume Cet article fait le point sur l’indication et le choix du traceur pour la TEP/TDM en cas de tumeurs neuroendocrines (TNE) de l’intestin grele qui sont les plus frequentes des TNE digestives. La TEP/TDM peut etre utilisee pour la recherche de la TNE primitive en cas de decouverte d’une metastase, pour la stadification afin de determiner la resecabilite, pour la restadification, l’optimisation et la determination de l’efficacite des modalites therapeutiques dans les formes etendues ou recidivantes. Actuellement, trois types de traceurs TEP sont utilises de facon courante : le FDG en cas de tumeur agressive surtout au niveau du duodenum ou du jejunum proximal, la FDOPA en cas de tumeur du jejunum distal ou de l’ileon, les analogues de la somatostatine marques au 68 Ga en cas de tumeur bien differenciee du duodenum ou du jejunum proximal ou bien quelle que soit la localisation de la TNE primitive si un traitement par analogue de la somatostatine est envisage afin de s’assurer de la surexpression des recepteurs de la somatostatine par les lesions.

Nodular lymphocyte predominant Hodgkin disease (NLPHL) differs clearly from classical Hodgkin lymphoma (cHL) by clinical presentation and more favorable outcome. Patients often present with early stage IA or IIA. Extranodal disease and B-symptoms are uncommon. Histologically, NLPHL is characterized by the presence of atypical "lymphocyte predominant cells" (LP cells) or "pop-corn" cells in a non-neoplastic and reactionnal nodular background of small mature B-lymphocytes. LP cells are negative for CD30 and positive for CD20, BCL6 and EMA (in half of the cases). FDG-PET plays an important role in evaluation of cHL and NLPHL for staging, therapy assessment and relapse. Historically, patients with NLPHL have been treated like patients with cHL, but their very favorable prognosis and the risk of late complications of chemotherapy and/or radiotherapy have led to a de-escalation in recent years. Patients with early stage could be treated by surgical adenectomy alone or associated with not intensive chemotherapy. Currently, there is no consensus regarding to the optimal treatment of patients with advanced stage. Rituximab used as monotherapy or in association with chemotherapy has achieved complete or partial responses. The outcome of NLPHL is singular by the frequent occurrence of late relapses and the risk of transformation into aggressive B lymphoma justifying an extended follow-up. Further prospective studies are needed to optimize treatment of these advanced and recurrent forms.