Current Radiopharmaceuticals - Volume 17, Issue 3, 2024

Diagnostic and interventional angiograms are instrumental in the multidisciplinary approach to CAD management, enabling accurate diagnosis and effective targeted treatments that significantly enhance patient care and cardiovascular outcomes. However, cath lab staff, including interventional cardiologists, is consistently exposed to ionizing radiation, which poses inherent health risks. Radiation exposure in the cath lab primarily results from the use of fluoroscopy and cineangiography during diagnostic and interventional procedures. Understanding these risks and implementing effective radiation protection measurements are imperative to ensure the well-being of healthcare professionals while delivering high-quality cardiac care. Prolonged and repeated exposure can lead to both deterministic and stochastic effects. Deterministic effects, such as skin erythema and tissue damage, are more likely to occur at high radiation doses. Interventional cardiologists and staff may experience these effects when safety measures are not rigorously followed. In fact, while ionizing radiation is essential in the practice of radiation cardiology ward, cath lab staff faces inherent risks from radiation exposure. Stochastic effects, on the other hand, are characterized by a probabilistic relationship between radiation exposure and the likelihood of harm. These effects include the increased risk of cancer, particularly for those with long-term exposure. Interventional cardiologists, due to their frequent presence in the cath lab, face a higher lifetime cumulative radiation dose, potentially elevating their cancer risk. Protective measures, including the use of lead aprons, thyroid shields, and radiation monitoring devices, play a crucial role in reducing radiation exposure for cath lab personnel. Adherence to strict dose optimization protocols, such as minimizing fluoroscopy time and maximizing distance from the radiation source, is also essential in mitigating these risks. Ongoing research and advancements in radiation safety technology are essential in further for minimizing the adverse effects of ionizing radiation in the cath lab.

Background: Lung and breast cancer are the most frequent causes of death from cancer globally. The objectives of this research were to evaluate the serum mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) and humanin levels in lung or breast cancer patients, and investigate the impacts of radiation therapy on the circulating levels of these peptides. Methods: 35 lung cancer patients, 34 breast cancer patients, and healthy volunteers as a control group were recruited in this prospective observatory research. Lung cancer patients with stage IIIA/IIIB were treated with paclitaxel-based chemotherapy plus radiotherapy (2 Gy per day, 30 times, 60 Gy total dose). Breast cancer stage IIA/IIB patients were treated with postoperative locoregional radiation therapy (2 Gy per day, 25 times, 50 Gy total dose). The ELISA method was used to detect serum humanin and MOTS-c levels during, before, and after radiotherapy. Results: We observed marked elevations in circulating MOTS-c, but not humanin levels in patients with lung cancer (P < 0.001). Radiation therapy led to a marked augmentation in MOTS-c levels in these patients (P < 0.001). On the other hand, there was a marked decline in humanin, but not MOTS-c, levels in breast cancer patients (P < 0.001). Conclusion: Our research has shown, for the first time, that increased MOTS-c and decreased humanin levels play a role in lung cancer and breast cancer, respectively. Additionally, radiotherapy modifies MOTS-c levels in patients with lung, but not breast cancer.

Background: Radiation exposure poses a significant threat to reproductive health, particularly the male reproductive system. The testes, being highly sensitive to radiation, are susceptible to damage that can impair fertility and overall reproductive function. The study aims to investigate the radioprotective effects of apigenin on the testis through histopathological evaluation. Materials and Methods: This research involved utilizing a total of 40 mice, which were randomly divided into eight groups of five mice each. The groups were categorized as follows: A) negative control group, B, C, and D) administration of apigenin at three different doses (0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg) respectively, E) irradiation group, and F, H, and I) administration of apigenin at three different doses (0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg) in combination with irradiation. The irradiation procedure involved exposing the mice to a 2Gy X-ray throughout their entire bodies. Subsequently, histopathological assessments were conducted seven days after the irradiation process. Results: The findings indicated that radiation exposure significantly impacted the spermatogenesis system. This research provides evidence that administering apigenin to mice before ionizing radiation effectively mitigated the harmful effects on the testes. Apigenin demonstrated radioprotective properties, positively influencing various parameters, including the spermatogenesis process and the presence of inflammatory cells within the tubular spaces. Conclusion: Apigenin can provide effective protection for spermatogenesis, minimize the adverse effects of ionizing radiation, and safeguard normal tissues.

Background: Employees may be exposed to different kinds of ionizing radiation at work. When ionizing radiation interacts with human cells, it can cause damage to the cells and genetic material. Therefore, one of the scientists' primary objectives has always been to create the best radiation-shielding materials. Glass could offer promising shielding material resulting from the high flexibility of composition, simplicity of production, and good thermal stability. Materials and Methods: The melt-quenching technique was used to create a glass having the following formula: 50% P2O5+20% Na2O+20% Fe2O3+10% X, where X = As2O3, SrO, BaO, CdO, and Sb2O3 mol %. The impact of the different heavy metal additions on the structure of the glass networks was studied using FTIR spectroscopy. Glass's ability to attenuate neutrons and/or charged particles has been theoretically investigated. The performance of the developed glass as a shield was examined by a comparison against commercial glass (RS 253 G18), ordinary concrete (OC), and water (H2O). Results: For charged particle radiations (Electrons, Protons, and Alpha), the shielding parameters like the mass stopping power, the projected range, and the effective atomic number were evaluated, where S5/Sb glass achieves the best performance. In the case of Neutrons, the results values reveal that S3/Ba glass ( ΣR = 0.105) is the best-modified glass for neutron shielding. Conclusion: Among all the investigated glasses, S5/Sb glass composition has a smaller range and provides superior protection against charged particles. In contrast, the S3/Ba glass composition is a superior choice for shielding against neutron radiation.

Background: Radiation exposure has been linked to the development of brain damage and cognitive impairment, but the protective effect and mechanism of Lycium barbarum pills (LBP) on radiation-induced neurological damage remains to be clarified. Methods: Behavioral tests and immunohistochemical studies were conducted to evaluate the protective effects of LBP extract (10 g/kg orally daily for 4 weeks) against radiation-induced damage on neurogenesis and cognitive function in Balb/c mice exposed to 5.5 Gy X-ray acute radiation. Results: The results showed that the LBP extract significantly improved body weight loss, locomotor activity and spatial learning and memory. Immunohistochemical tests revealed that the LBP extract prevented the loss of proliferating cells, newly generated neurons and interneurons, especially in the subgranular area of the dentate gyrus. Conclusion: The findings suggest that LBP is a potential neuroprotective drug for mitigating radiation-induced neuropsychological disorders.

Objective: This study aimed to construct a nomogram based on clinical and ultrasound (US) features to predict breast malignancy in males. Methods: The medical records between August, 2021 and February, 2023 were retrospectively collected from the database. Patients included in this study were randomly divided into training and validation sets in a 7:3 ratio. The models for predicting the risk of malignancy in male patients with breast lesions were virtualized by the nomograms. Results: Among the 71 enrolled patients, 50 were grouped into the training set, while 21 were grouped into the validation set. After the multivariate analysis was done, pain, BI-RADS category, and elastography score were identified as the predictors for malignancy risk and were selected to generate the nomogram. The C-index was 0.931 for the model. Concordance between predictions and observations was detected by calibration curves and was found to be good in this study. The model achieved a net benefit across all threshold probabilities, which was shown by the decision curve analysis (DCA) curve. Conclusion: We successfully constructed a nomogram to evaluate the risk of breast malignancy in males using clinical and US features, including pain, BI-RADS category, and elastography score, which yielded good predictive performance.

Introduction: The most important toxicity of transarterial radioembolization therapy applied in liver malignancies is radiation pneumonitis and fibrosis due to hepatopulmonary shunt of Yttrium-90 (⁹⁰Y) microspheres. Currently, Technetium-99m macroaggregated albumin (^99mTc-MAA) scintigraphic images are used to estimate lung shunt fraction (LSF) before treatment. The aim of this study was to create a phantom to calculate exact LFS rates according to ^99mTc activities in the phantom and to compare these rates with LSF values calculated from scintigraphic images. Materials and Methods: A 3D-printed lung and liver phantom containing two liver tumors was developed from Polylactic Acid (PLA) material, which is similar to the normal-sized human body in terms of texture and density. Actual %LSFs were calculated by filling phantoms and tumors with ^99mTc radionuclide. After the phantoms were placed in the water tank made of plexiglass material, planar, SPECT, and SPECT/CT images were obtained. The actual LSF ratio calculated from the activity amounts filled into the phantom was used for the verification of the quantification of scintigraphic images and the results obtained by the Simplicity⁹⁰Y^TM method. Results: In our experimental model, LSFs calculated from ^99mTc activities filled into the lungs, normal liver, small tumor, and large tumor were found to be 0%, 6.2%, 10.8%, and 16.9%. According to these actual LSF values, LSF values were calculated from planar, SPECT/CT (without attenuation correction), and SPECT/CT (with both attenuation and scatter correction) scintigraphic images of the phantom. In each scintigraphy, doses were calculated for lung, small tumor, large tumor, normal liver, and Simplicity⁹⁰Y^TM. The doses calculated from planar and SPECT/CT (NoAC+NoSC) images were found to be higher than the actual doses. The doses calculated from SPECT/CT (with AC+with SC) images and Simplicity⁹⁰Y^TM were found to be closer to the real dose values. Conclusion: LSF is critical in dosimetry calculations of ⁹⁰Y microsphere therapy. The newly introduced hepatopulmonary shunt phantom in this study is suitable for LSF verification for all models/brands of SPECT and SPECT/CT devices.

Background: Prostate-specific membrane antigen (PSMA) is an ideal target for molecular imaging and targeted radionuclide therapy in prostate cancer. Consequently, various PSMA ligands were developed. Some of these molecules are functionalized with a chelator that can host radiometals, such as ⁶⁸Ga for PET imaging. The ⁶⁸Ga radiolabeling step benefits from process automation, making it more robust and reducing radiation exposure. Objective: To design a single automated radiolabeling protocol for the GMP-compliant preparation of [⁶⁸Ga]Ga-PSMA-11, transposable to the production of [⁶⁸Ga]Ga-PSMA-617 and [⁶⁸Ga]Ga-PSMA-I Methods: A GAIA^® synthesis module and a GALLIAD^® generator were used. Radio-TLC and radio-HPLC methods were validated for radiochemical purity (RCP) determination. Three [⁶⁸Ga]Ga-PSMA-11 validation batches were produced and thoroughly tested for appearance and pH, radionuclide identity and purity, RCP, stability, residual solvent and sterility. Minimal modifications were made to the reagents and disposables for optimal application to other PSMA ligands. Results: [⁶⁸Ga]Ga-PSMA-11 for clinical application was produced in 27 min. The 3 validation batches met the quality criteria expected by the European Pharmacopoeia to allow routine production. For optimal transposition to PSMA-617, the solid phase extraction cartridge was changed to improve purification of the radiolabeled product. For application to PSMA-I, the buffer solution initially used was replaced by HEPES 2.7 M to achieve good radiochemical yields. Residual HEPES content was checked in the final product and was below the Ph. Eur. threshold. Conclusion: A single automated radiolabeling method on the GAIA^® module was developed and implemented for ⁶⁸Ga radiolabeling of 3 PSMA ligands, with slight adjustments for each molecule.

Aim: Efficient synthesis of precursor from commercially available starting materials and automated radiosynthesis of [¹¹C]PiB using commercially available dedicated [¹¹C]- Chemistry module from the synthesized precursor. Background: [¹¹C]PiB is a promising radiotracer for PET imaging of β-Amyloid, advancing Alzheimer's disease research. The availability of precursors and protocols for efficient radiolabelling foster the applications of any radiotracer. Efficient synthesis of PiB precursor was performed using anisidine and 4-nitrobenzoyl chloride as starting materials in 5 steps, having addition, substitutions, and cyclization chemical methodologies. This precursor was used for fully automated radiosynthesis of [¹¹C]PiB in a commercially available synthesizer, MPS-100 (SHI, Japan). The synthesized [¹¹C]PiB was purified via solid-phase methodology, and its quality control was performed by the quality and safety criteria required for clinical use. Methods: The synthesis of desired precursors and standard authentic compounds started with commercially available materials with 70-80% yields. The standard analytical methods were characterized all synthesized compounds. The fully automated [¹¹C]-chemistry synthesizer (MPS-100) used for radiosynthesis of [¹¹C]PiB with [¹¹C]CH3OTf acts as a methylating agent. For radiolabelling, varied amounts of precursor and time of reaction were explored. The resulting crude product underwent purification through solid-phase cartridges. The synthesized radiotracer was analyzed using analytical tools such as radio TLC, HPLC, pH endo-toxicity, and half-life. Results: The precursor for radiosynthesis of [¹¹C]PiB was achieved in excellent yield using simple and feasible chemistry. A protocol for radiolabelling of precursor to synthesized [¹¹C]PiB was developed using an automated synthesizer. The crude radiotracer was purified by solid-phase cartridge, with a decay-corrected radiochemical yield of 40±5% and radiochemical purity of more than 97% in approx 20 minutes (EOB). The specific activity was calculated and found in a 110-121 mCi/μmol range. Conclusion: A reliable methodology was developed for preparing precursor followed by fully automated radiolabeling using [¹¹C]MeOTf as a methylating agent to synthesize [¹¹C]PiB. The final HPLC-free purification yielded more than 97% radiochemical purity tracer within one radionuclide half-life. The method was reproducible and efficient for any clinical center.