Parkinson’s disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, leading to alteration of the integrity of dopaminergic transporters (DATs). In recent years, some radiopharmaceuticals have been used in the clinic to evaluate the integrity of DATs. These include tropane derivatives such as radiolabeled β-CIT and FP-CIT with iodine-123 (123I), and TRODAT-1 with metastable technetium-99 (99mTc). Radiolabeling of β-CIT with radioactive iodine is based on electrophilic radioiodination using oxidizing agents, such as Chloramine T or Iodo-Gen®. For the first time, the present work performed a comparative study of the radiolabeling of β-CIT with iodine-131 (131I), using either Chloramine T or Iodo-Gen® as oxidizing agents, in order to improve the radiolabeling process of β-CIT and to choose the most advantageous oxidizing agent to be used in nuclear medicine. Both radiolabeling methods were similar and resulted in high radiochemical yield (> 95%), with suitable 131I-β-CIT stability up to 72 h. Although Chloramine T is a strong oxidizing agent, it was as effective as Iodo-Gen® for β-CIT radiolabeling with 131I, with the advantage of briefer reaction time and solubility in aqueous medium.

Prostate-specific membrane antigen (PSMA) is a glycoprotein present in the prostate, that is overexpressed in prostate cancer (PCa). Recently, PSMA-directed radiopharmaceuticals have been developed, allowing the pinpointing of tumors with the Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) imaging techniques. The aim of the present work was to standardize and validate an automatic synthesis module-based radiolabeling protocol for [68Ga]Ga-PSMA-11, as well as to produce a radiopharmaceutical for PET imaging of PCa malignancies. [68Ga]Ga-PSMA-11 was evaluated to determine the radiochemical purity (RCP), stability in saline solution and serum, lipophilicity, affinity to serum proteins, binding and internalization to lymph node carcinoma of the prostate (LNCaP) cells, and ex vivo biodistribution in mice. The radiopharmaceutical was produced with an RCP of 99.06 ± 0.10%, which was assessed with reversed-phase high-performance liquid chromatography (RP-HPLC). The product was stable in saline solution for up to 4 h (RCP > 98%) and in serum for up to 1 h (RCP > 95%). The lipophilicity was determined as −3.80 ± 0.15, while the serum protein binding (SPB) was <17%. The percentages of binding to LNCaP cells were 4.07 ± 0.51% (30 min) and 4.56 ± 0.46% (60 min), while 19.22 ± 2.73% (30 min) and 16.85 ± 1.34% (60 min) of bound material was internalized. High accumulation of [68Ga]Ga-PSMA-11 was observed in the kidneys, spleen, and tumor, with a tumor-to-contralateral-muscle ratio of >8.5 and a tumor-to-blood ratio of >3.5. In conclusion, an automatic synthesis module-based radiolabeling protocol for [68Ga]Ga-PSMA-11 was standardized and the product was evaluated, thus verifying its characteristics for PET imaging of PCa tumors in a clinical environment.

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Objective:To present the result of upgrading a clinical gamma-camera to be used to obtain in vivo tomographic images of small animal organs, and its application to register cardiac, renal and neurological images.Methods:An updated version of the miniSPECT upgrading device was built, which is composed of mechanical, electronic and software subsystems. The device was attached to a Discovery VH (General Electric Healthcare) gamma-camera, which was retired from the clinical service and installed at the Centro de Imagem Pré-Clínica of the Hospital Israelita Albert Einstein. The combined system was characterized, determining operational parameters, such as spatial resolution, magnification, maximum acceptable target size, number of projections, and acquisition and reconstruction times.Results:Images were obtained with 0.5mm spatial resolution, with acquisition and reconstruction times between 30 and 45 minutes, using iterative reconstruction with 10 to 20 iterations and 4 projection subsets. The system was validated acquiring in vivo tomographic images of the heart, kidneys and brain of normal animals (mice and adult rats), using the radiopharmaceuticals technetium-labeled hexakis-2-methoxy-isobutyl isonitrile (99mTc-Sestamibi), technetium-labeled dimercaptosuccinic acid (99mTc-DMSA) and technetium-labeled hexamethyl propyleneamine oxime (99mTc-HMPAO).Conclusion:This kind of application, which consists in the adaptation for an alternative objective of already existing instrumentation, resulted in a low-cost infrastructure option, allowing to carry out large scale in vivo studies with enhanced quality in several areas, such as neurology, nephrology, cardiology, among others.