Comparison of Accuracy in Calculation of Absorbed Dose to the Kidneys Following Radioligand Therapy with 177Lu-DKFZ-PSMA-617 by Two Different Background Correction Methods.

Background: To improve the accuracy of activity image quality, scatter correction is a critical method. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following radioligand therapy (RLT) with 177Lu-DKFZ-PSMA-617 by two different methods of background correction in the conjugate view method. Materials and Methods: This study involved 10 patients. The individualized patient dosimetry calculations were based on whole-body planar scintigraphy images acquired in 10 patients with a mean age of 71.4 ± 6.07 years (range 63-85 years) at approximately 0-2 h, 4-6 h, 18-24 h, and 36-48 h after administration of the mean 6253 ± 826.4 MBq (range 5500-7400 MBq) of 177Lu-DKFZ-PSMA-617. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Eventually, the absorbed dose of radiation was calculated using Medical Internal Radiation Dose formalism. Results: The dose per unit of injected activity (mGy/MBq) ± standard deviation for kidney using Buijs and conventional methods was 1.05 ± 0.11 and 0.63 ± 0.14, respectively. Conclusion: The Buijs background correction method was more accurate than the conventional method.

Radiation Dose to Medical Staff from Administering 177Lu-PSMA-DKFZ-617 Therapy.

The number of radioligand therapy applications for metastatic castration-resistant prostate cancer has been continuously rising in most nuclear medicine departments in Iran, but to our knowledge, no one has studied the dose to staff who perform treatment procedures. The current study aimed to determine the external radiation dose received by staff who, using or not using a lead shield, treat patients with 177Lu-prostate-specific membrane antigen therapy. Methods: This study used a personal thermoluminescent digital survey meter to measure dose rates to staff at various distances from patients and determined the average time spent by staff at these distances. The deep-dose equivalent to staff was obtained. Results: The measured deep-dose equivalent to staff per patient was within the range of 1.8-5.2 mSv using a 2-mm lead shield and 3.3-8.1 mSv not using the shield. The shield markedly reduced the external dose to staff. Conclusion: The skill and accuracy of staff, and the speed with which they act, can directly affect their received dose.

Patient-Specific Dosimetry in Radioligand Therapy (RLT) for Metastatic Prostate Cancer Using 177Lu-DKFZ-PSMA-617.

PURPOSE: 177Lu-DKFZ-PSMA-617 is a promising treatment for patients with metastatic prostate cancer. Specific dosimetry for each patient is an important factor in planning the patient's treatment process. This study aimed to perform an image-based absorbed dose calculation for the treatment of metastatic prostate cancer with 177Lu-DKFZ-PSMA-617. METHODS: The individualized patient dosimetry calculations were based on whole-body planar scintigraphy images acquired in 10 patients with a mean age of 71.4 ± 6.07 years (range 63-85 years) at approximately 0-2 h, 4-6 h, 18-24 h, and 36-48 h after administration of the mean 6253 ± 826.4 MBq (range 5500-7400 MBq) of 177Lu-DKFZ-PSMA-617. Time-activity curves were generated for various organs. For count conversion to activities, calibration factors were calculated. Finally, the absorbed dose for an individual cycle was calculated using IDIAC-DOSE 2.1 software. RESULTS: On average, the calculated absorbed dose for the kidneys and salivary glands were 0.46 ± 0.09 mGy/MBq and 0.62 ± 0.07 mGy/MBq, respectively. CONCLUSIONS: Based on the results, the177Lu-PSMA-617 therapy is a safe method for the treatment of castration-resistant prostate cancer patients. Large inter-individual variations in organ dose were found, demonstrating the need for patient-specific dosimetry and treatment planning.

MicroRNA: A Potential Diagnosis for Male Infertility.

Male infertility is one of the major global health problems, in particular, in more than half of the affected men. Genetic factors are important for identifying men with idiopathic infertility along with semen analysis. Valid and useful information can be obtained through non-invasive molecular research. Among these, small single-stranded non-coding RNA molecules of microRNAs (abbreviated miRNAs) are non-invasive biomarkers with a diagnostic value by regulating the post-transcriptional gene silence through repression and prevention of the translation process. The association between various types of male infertility and miRNA regulation changes has been evaluated to understand the biological function of miRNA and gene targets. Accordingly, further study of the function of miRNAs associated with reproductive disorders could lead researchers to further understand the molecular mechanisms of male infertility in order to find effective biomarkers and therapeutic strategies. Therefore, the present review article aimed at scrutinizing those researches investigating the altered miRNA expression in testicles, epididymis, and spermatozoa.

Role of Oxidative Stress and Antioxidant Supplementation in Male Fertility.

Nearly 15% of couples experience infertility as a universal health issue. About 50% of infertility cases have been known to be associated with the male partner . Oxidative stress (OS) represents an imbalance in the level of reactive oxygen species (ROS) and anti-oxidants. In fact, OS has been considered as one of the popular pathologies reported in about 50% of all infertile males. Therefore, the increased level of ROS may result in infertility via DNA damages or lipid peroxidation (LPO) as well as the inactivation of enzymes and oxidation of protiens in spermatozoa. Basically, OS results from lifestyle variables. As the absence of antioxidants and the respective deficiencies in the semen cause OS, variations in the lifestyle and anti-oxidant regimes may be advantageous to treatment strategies for resolving such an issue. Actually, anti-oxidants like vitamins E and C, glutathione, coenzyme-Q10, carnitines, selenium, Nacetylcysteine, carotenoids, zinc, and pentoxifylline decline the OS-induced sperm damages. Therefore, the present review overviews the oxidative biochemistry associated with sperm health and identifies which men would be most at risk of oxidative infertility. Hence, the review would show the techniques provided to diagnose OS and diverse therapeutic options.