Interim FDG-PET/CT for therapy monitoring and prognostication in Hodgkin's Lymphoma.

The aim of the study was to assess the predictive value of interim FDG-PET/CT (iPET) in patients with Hodgkin's lymphoma (HL) treated with Adriamycin, bleomycin, vinblastine and dacarbazine (ABVD) chemotherapy. A total of 245 consecutive patients with de novo HL between 12/2013 and 12/2017 were evaluated retrospectively. All patients were treated with upfront ABVD, performed PET/CT scans at baseline, after 2 cycles (interim PET, iPET2) or 4 cycles (iPET4) and at the end of therapy, and followed up for at least 6 months after therapy. The response status on iPET was defined according to the standard five-point Deauville scores (DS) as follows: complete metabolic response (CMR, DS 1-3) and non-complete metabolic response (nCMR) (DS 4 and 5). End-of-treatment (EoT) response was assessed by FDG-PET/CT and if needed biopsy confirmation of PET-positive findings. The association between iPET and EoT response was investigated using logistic regression analysis. Survival analysis was performed using the Cox regression hazard model and Kaplan-Meier methods. Sixty-nine patients underwent iPET-2 and 176 iPET-4. No association was found between the timing of iPET and iPET response status (P-value = 0.71). Two hundred and one patients (82%) had iPET-CMR and 44 (18%) iPET -nCMR. iPET was strongly associated with EoT response status: 194/201 (96 .5%) of iPET-CMR had a complete response at the EoT while only 21/44 (47.7%) of patients with iPET-nCMR presented a complete response at EoT (P-value < 0.0001). The median follow-up was 32 months (range 6-81). Patients with iPET-CMR presented a better outcome with 91% 3 y event-free-survival (EFS) and 95% 3 y overall survival (OS) than those with iPET-nCMR (41 and 86%, respectively, P-value < 0.0001). In multivariable analyses, iPET retained an independent prognostic factor of EFS and OS (P-value < 0.0001 and P-value = 0.002, respectively). iPET is highly predictive of outcome of HL patients treated with ABVD and allows to tailor therapy to the individual patient.

68Ga-DOTATOC Embolus Manifestation and Spontaneous Resolution by PET/CT.

68Ga-labeled somatostatin receptor analogs physiologic distribution patterns have become recognizable among nuclear medicine physicians because of the increasing routine clinical use of this modality in the work-up of neuroendocrine tumors. Some pitfalls during 68Ga-labeled somatostatin receptor PET/CT have recently been reported as causes of misdiagnoses. Iatrogenic microembolism as a cause of 18F-FDG embolus is well-established; however, 68Ga-DOTATOC embolus is not well documented in the literature. In the current case, the presence and the spontaneous resolution of the 68Ga-labeled somatostatin receptor analogs embolus during sequential PET/CT are nicely demonstrated. Awareness of this incidental finding would avoid misdiagnosis and unnecessary investigations.

68Ga DOTA-TOC Uptake in Non-ossifying Fibroma: a Case Report.

Non-ossifying fibroma (NOF) is a common benign bone tumor with a high probability of occurrence in children and adolescents. It is commonly seen in the metaphysis of long bones, eccentrically located, and can coexist with other malignant tumors such as neuroendocrine tumors (NET). To date, plain radiographs play a major role in the diagnosis of these benign bone tumors. Herein, we report the case of a 13-year-old male patient who was diagnosed with pulmonary NET and underwent right lung lobectomy for a hilar mass which later revealed a well-differentiated NET. The follow-up 68Ga DOTA-TOC PET/CT showed a focal somatostatin receptor expression in the left distal femur, with corresponding CT component findings of a well-defined osteolytic bone lesion located within the medial aspect of the left distal femoral metaphysis, strongly indicative of NOF. To the best of our knowledge, this is the first reported case of such an occurrence.