SPECT with 67Ga Citrate in the Diagnosis of Systemic Sarcoidosis

Purpose: To study the possibilities of using 67Ga-citrate in patients with systemic manifestations of sarcoidosis to identify foci of pathological accumulation of the drug and assess the degree of process activity. Material and methods: Radionulide study with 67Ga-citrate was performed in 140 patients with respiratory sarcoidosis and suspected extrapulmonary localization. In addition, all patients underwent X-ray examination of the lungs, MSCT of the organs of the chest and abdominal cavity, SPECT of the lungs with radiopharmaceutical macroaggregates of albumin, ultrasound of the abdomen, pelvis, MRI of the head was performed in 16 patients with suspected neurosarcoidosis. Results: Most patients (n = 125) showed changes in the lungs, manifested by a bright glow (yellow or purple) on the computer screen, which indicated a pronounced impaired function of lymphoid tissue. In 22 patients, the changes were recurrent. The results correlated with published data on damage to the nervous system (r = 0.96), musculoskeletal system (r = 0.97), parotid glands (r = 0.91), liver, spleen (r = 0.83) . At the same time, the results for eye damage (r = 0.23), ENT organs (r = 0.15), intestines (r = 0.48) were significantly different. In our study, no heart lesions were detected in any case. Conclusions: The use of positive scintigraphy with Ga-67 citrate, taking into account the whole body scan and SPECT of areas of interest of interest (chest cavity, abdominal cavity, head, pelvis) is effective for the diagnosis of systemic sarcoidosis and in determining the activity of the process. The study is recommended to be performed 72 hours after intravenous administration of the drug. The combination of CT, MRI and radionuclide studies allows you to obtain reliable information about the activity of the process, to identify the localization of increased metabolic activity, that is, the topography of active sarcoidosis.

In situ lymphoma imaging in a spontaneous mouse model using the Cerenkov Luminescence of F-18 and Ga-67 isotopes

We aimed to study lymphoma diagnostics by Cerenkov luminescence imaging (CLI). We monitored the dissemination of a spontaneous high-grade mouse lymphoma (Bc.DLFL1) in early stage; advanced stage; and terminal stage with in vivo 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET) / magnetic resonance imaging (MRI) and 67Ga-citrate single photon emission computed tomography (SPECT) / MRI. In vivo imaging was combined with ex vivo high resolution CLI. The use of CLI with Fluorine-18 and Gallium-67 to select infiltrated lymph nodes for tumor staging pathology was thus tested. At advanced stage, [18F]FDG PET/MRI plus ex vivo CLI allowed accurate detection of [18F]FDG accumulation in lymphoma-infiltrated tissues. At terminal stage we detected tumorous lymph nodes with SPECT/MRI and we could report the Cerenkov light emission of 67Ga. CLI with 67Ga-citrate revealed lymphoma accumulation in distant lymph node locations, unnoticeable with only MRI. Flow cytometry and immunohistochemistry confirmed these imaging results. Our study promotes the combined use of PET and CLI in preclinical studies and clinical practice. Heterogeneous [18F]FDG distribution in lymph nodes detected at sampling surgery has implications for tissue pathology processing and could direct therapy. The results with 67Ga also point to the opportunities to further apply suitable SPECT radiopharmaceuticals for CLI.

Molecular Imaging of Pulmonary Inflammation and Infection

Infectious and inflammatory pulmonary diseases are a leading cause of morbidity and mortality worldwide. Although infrequently used in this setting, molecular imaging may significantly contribute to their diagnosis using techniques like single photon emission tomography (SPET), positron emission tomography (PET) with computed tomography (CT) or magnetic resonance imaging (MRI) with the support of specific or unspecific radiopharmaceutical agents. 18F-Fluorodeoxyglucose (18F-FDG), mostly applied in oncological imaging, can also detect cells actively involved in infectious and inflammatory conditions, even if with a low specificity. SPET with nonspecific (e.g., 67Gallium-citrate (67Ga citrate)) and specific tracers (e.g., white blood cells radiolabeled with 111Indium-oxine (111In) or 99mTechnetium (99mTc)) showed interesting results for many inflammatory lung diseases. However, 67Ga citrate is unfavorable by a radioprotection point of view while radiolabeled white blood cells scan implies complex laboratory settings and labeling procedures. Radiolabeled antibiotics (e.g., ciprofloxacin) have been recently tested, although they seem to be quite unspecific and cause antibiotic resistance. New radiolabeled agents like antimicrobic peptides, binding to bacterial cell membranes, seem very promising. Thus, the aim of this narrative review is to provide a comprehensive overview about techniques, including PET/MRI, and tracers that can guide the clinicians in the appropriate diagnostic pathway of infectious and inflammatory pulmonary diseases.

GALLIUM-67 CITRATE USED AS A TRACER OF ACETONE PRODUCTION ROUTE

In this work the pathway of the chemical product and the kinetics parameters were evaluated in a laboratory plant settled, using 0.4 GBq (10 mL) of 67Ga citrate as radiotracer and 18 NaI(Tl) radiation detectors. The AnaComp program was used to estimate the kinetic para ameters of the acetone production. The yield of the acetone production was estimated by the percentage ratio between the areas under the curve (AUC) of the curve profiles of the final product compartment divided by the concentration found inside the chemical reactor whose result was 87% yield during the first 30 minutes of reaction.

SPECT/CT with radiolabeled somatostatin analogues in the evaluation of systemic granulomatous infections

Objective: To evaluate SPECT/CT with radiolabeled somatostatin analogues (RSAs) in systemic granulomatous infections in comparison with gallium-67 (67Ga) citrate scintigraphy. Materials and Methods: We studied 28 patients with active systemic granulomatous infections, including tuberculosis, paracoccidioidomycosis, pneumocystosis, cryptococcosis, aspergillosis, leishmaniasis, infectious vasculitis, and an unspecified opportunistic infection. Of the 28 patients, 23 had started specific treatment before the study outset. All patients underwent whole-body SPECT/CT imaging: 7 after injection of 99mTc-EDDA-HYNIC-TOC, and 21 after injection of 111In-DTPA-octreotide. All patients also underwent 67Ga citrate imaging, except for one patient who died before the 67Ga was available. Results: In 20 of the 27 patients who underwent imaging with both tracers, 27 sites of active disease were detected by 67Ga citrate imaging and by SPECT/CT with an RSA. Both tracers had negative results in the other 7 patients. RSA uptake was visually lower than 67Ga uptake in 11 of the 20 patients with positive images and similar to 67Ga uptake in the other 9 patients. The only patient who did not undergo 67Ga scintigraphy underwent 99mTc-EDDA-HYNIC-TOC SPECT/CT-guided biopsy of a lung cavity with focal RSA uptake, which turned to be positive for aspergillosis. Conclusion: SPECT/CT with 99mTc-EDDA-HYNIC-TOC or 111In-DTPA-octreotide seems to be a good alternative to 67Ga citrate imaging for the evaluation of patients with systemic granulomatous disease.