This study was designed to evaluate the accuracy of detecting pulmonary embolism (PE) using the Technegas SPECT/CT combined with ⁶⁸Ga PET/CT in a rabbit model. One hour after artificial PE (n = 6) and sham (n = 6) models were created, Technegas SPECT/CT ventilation and ⁶⁸Ga-MAA PET/CT perfusion scan (V/Q scan) were performed. Ventilation imaging was performed first on all cases. Technegas SPECT/CT and ⁶⁸Ga-MAA PET/CT images were evaluated by a nuclear medicine physician who recorded the presence, number, and location of PE on a per-lobe basis. The sensitivity, specificity, and accuracy of Technegas SPECT/CT and ⁶⁸Ga-MAA PET/CT for detecting PE were calculated using a histopathological evaluation as a reference standard. A total of 60 lung lobes were evaluated in 12 rabbits, and PE was detected in 20 lobes in V/Q scans and histopathological analysis. The overall sensitivity, specificity, and accuracy were 100%, 100%, and 100%, respectively, for both the Technegas SPECT/CT and ⁶⁸Ga-MAA PET/CT V/Q scans. Technegas/⁶⁸Ga-MAA V/Q scans have good sensitivity, specificity, and accuracy in the detection of PE in this animal model study.

The prostate-specific membrane antigen (PSMA) represents an ideal biomarker for molecular imaging. Various PSMA-targeted radioligands are available for prostate cancer imaging. In this study, labeling of PSMA I&T with 68Ga, as well as validation of the radiochemical purity of the synthesis product by reverse phase radio high-performance liquid chromatography (HPLC) method are intended. Since the standard procedure for the quality control (QC) was not available, definition of chemical and radiochemical purity of 68Ga-PSMA I&T was carried out according to the Q2 (R1) ICH guideline. The standard QC tests were analyzed with Scintomics 8100 radio-HPLC system equipped with a radioactivity detector. The method was evaluated in terms of linearity, precision and accuracy, LOQ, robustness parameters, and specificity. To assess the radiochemical and chemical purity of 68Ga-PSMA I&T, the developed method was validated to apply safely to patients. An excellent linearity was found between 1μg/mL and 30 μg/mL, with a limit of detection and limit of quantitation of 0.286 μg/mL and 0.866 μg/mL, respectively for 68Ga-PSMA I&T. The recovery was 96.8 ± 3.8%. The quality control of the final product was performed many times with validated radio-HPLC method and was found to comply with ICH requirements, thus demonstrating the accuracy and robustness of the method for routine clinical practice.

Background/aim: Especially suitable for PET due to its nuclear physical and radiochemical properties, the positron emitter Gallium-68 (⁶⁸Ga) occurs by electron capture from Germanium-68 (⁶⁸Ge). In such a radionuclide generator, the germanium is bound to an insoluble, inert column matrix and forms a secular radioactive balance with 68Ga obtained in the hour. As a result of the limited radiochemical selectivity of the elution process, the eluate obtained is basically contaminated with the main nuclide traces, so that the eluate becomes a mixture of ⁶⁸Ga and ⁶⁸Ge radionuclides. Also, the generator eluate contains a number to metal cations that reduce specific radioactivity and can compete with 68Ga. The presence of toxic metal that can be found in the eluate carries the risks of contamination at every step from the production of generators to radiopharmaceutical production. Materials and method: In our study, by collecting the eluate of the ⁶⁸Ge/⁶⁸Ga generators used with different identities in different centers in Turkey, we report comparative analysis of metal contamination in the generator eluate. The eluates of 68Ge/68Ga generators to five different identities were collected. Eluates were analyzed by inductively coupled plasma–mass spectrometry. Results and Conclusion: As a result, each generator contains metallic impurities different from its certificate.

Gallium-68 is an ideal research and hospital-based PET radioisotope. The uptake mechanism of Gallium citrate is a combination of specific and non-specific processes, for example, vasodilatation, increased vascular permeability, plasma transferrin binding and lactoferrin and siderophores. In this study, by applying the ⁶⁸Ge/⁶⁸Ga generator product, a simple technique for the synthesis and quality control of ⁶⁸Ga-citrate was introduced and was followed by preliminary animal studies. The synthesis of ⁶⁸Ga-citrate was performed with a cationic method using the Scintomics automated synthesis system (Scintomics GmbH GRP module 4V). Since the standard procedure for quality control (QC) was not available, the definition of chemical and radiochemical purity of ⁶⁸Ga-citrate was carried out according to the ICH Q2(R1) guideline. The standard QC tests were analysed with Scintomics 8100 radio-HPLC system equipped with a radioactivity detector. In this study, a New Zealand rabbit weighing 2520 g was used for PET/CT images. ⁶⁸Ga-citrate synthesis was performed by a cationic method without using organic solvents. The labelling efficiency was found to be >98%. The HPLC method used to assess the radiochemical purity of ⁶⁸Ga -citrate was validated as rapid, accurate and reproducible enough to apply it to patients safely. The physiological distribution of ⁶⁸Ga-citrate was investigated in a healthy rabbit. The blood pool, liver, spleen, kidneys and growth plates were the most common sites of ⁶⁸Ga-citrate involvement.