Purpose: We developed and validated the accuracy of a method to calculate the arterial input function (AIF) from PET images only, without the need for the arterial blood sampling, in the absolute quantitation of functional parametric values in ¹⁵O- gas PET examinations. Methods: We extended the method reported by Iguchi et al. (2013) to derive the arterial input function, thus absolute quantitative functional parametric images of cerebral perfusion and oxygen metabolism by a reference tissue approach. We compared shapes of the AIF and reproducibility of the absolute functional values. Existing test data that were carried out with the continuous arterial blood sampling were used for this study. Results: The estimated AIF shapes agreed well with those estimated from the continuous arterial blood sampling. The error range of the absolute quantitative values was approximately ±20%, with a fairly well reproducibility in the relative values being less than 3%. Conclusion: The AIFs by this method were reproducible. Although the absolute quantitative values varied depending on the assumed functional values in the reference region in individual cases, the relative images showed fairly good agreement with the results from the standard technique that employed the arterial blood sampling. The present technique may provide significant contribution to clinical examination.

Objective: To perform an exploratory analysis on the safety and effectiveness of radium-223 (Ra-223) by patient baseline age, using the results of a post-marketing surveillance study of Ra-223 in castration-resistant prostate cancer patients with bone metastasis in Japan. Method: The safety analysis population of 296 patients was stratified into two groups based on age (<75 and ≥ 75 years-old [yo]), and their characteristics, drugrelated treatment-emergent adverse events (TEAEs), and clinical laboratory values were evaluated. Additionally, these endpoints were evaluated in patients aged ≥ 80 yo. Results: There were 148 patients in each of the <75-yo and ≥ 75-yo age groups, and 69 patients in the ≥ 80-yo age group. The characteristics of patients in the <75-yo group were suggestive of more aggressive disease at diagnosis of prostate cancer and a greater proportion of patients had prior chemotherapy compared with patients in the ≥ 75-yo age group. The incidences of overall drugrelated TEAEs and drug-related hematological TEAEs were slightly higher in the <75-yo age group; however, there was little difference in the incidences of drug-related TEAEs leading to drug discontinuation (1.4–4.1%) between patient groups. Changes in total alkaline phosphatase and prostate-specific antigen values were similar in all groups. Conclusions: Ra-223 therapy seemed tolerable regardless of age in real-world practice in Japan. Especially, there were no new safety concerns of Ra-223 in elderly patients.

Internal radiation therapy using 3-iodobenzylguanidine (¹³¹I) injection (¹³¹I-MIBG injection) will be applied in actual clinical practice soon. However, the NHI medical technical fee for the use of 131I-MIBG injection has not yet been set. The Japanese Society of Nuclear Medicine surveyed health resource use for internal radiation therapy using ¹³¹I via questionnaires sent to medical institutions that have used ¹³¹I-MIBG injection. Results showed that the necessary cost per patient is 1,912,671 JPY, which was based on the Draft Proposal for Medical Examination Value (Ver. 7.2) of the Japanese Health Insurance Federation for Surgery. ¹³¹I-MIBG injection is supposed to be administered once to each patient and the patient is followed up for 4 months after administration. The fee per treatment is calculated to be 478,168 JPY per month. The appropriate NHI medical technical fee is thus considered to be 47,817 points per month per patient per treatment, which can be claimed up to 4 times.

Internal radiation therapy using lutetium-177(¹⁷⁷Lu)-DOTA-TATE injection will be applied in actual clinical practice soon. However, the NHI medical technical fee for the use of ¹⁷⁷Lu-DOTA-TATE injection has not yet been set. The Japanese Society of Nuclear Medicine surveyed health resource use in internal radiation therapy using ¹⁷⁷Lu via questionnaires sent to medical institutions that have used ¹⁷⁷Lu-DOTA-TATE injection. Results showed that the necessary cost per patient is 1,912,404 JPY, based on the Draft Proposal for Medical Examination Value (Ver. 7.2) of the Japanese Health Insurance Federation for Surgery. ¹⁷⁷Lu-DOTA-TATE injection is supposed to be administered 4 times to each patient at 8-week intervals, and the fee per treatment was calculated to be 478,101 JPY. The appropriate NHI medical technical fee is thus considered to be 47,810 points per patient per treatment, which can be claimed 4 times per patient. In addition, it costs 649,030 JPY per patient to take special measures to make the hospital room similar to the radiation therapy room. The cost other than the basic hospitalization fee per day was calculated to be 81,129 JPY. The appropriate additional points for NHI basic hospitalization fee is thus considered to be 8,113 points per patient per day.

Quality of the ⁶⁸Ga solution eluted from a ⁶⁸Ge/⁶⁸Ga generator (Galli Eo^®) was evaluated. Elution was performed 488 times from 21 to 484 days (ca. 15 months) after the calibration date. The eluted ⁶⁸Ga activity was 329 MBq to 1,148 MBq, which decreased with the decay of ⁶⁸Ge, but no significant change was observed in the elution yields (62.8±2.2%). The half-life of the eluted radioactivity was 67.8±0.1 min, the radionuclide purity of ⁶⁸Ga was ≥99.9%, the ⁶⁸Ge breakthrough was 0.000024 ±0.000004%, and the radiochemical purity of ⁶⁸Ga³⁺ was 99.7±0.2%. Fe and Zn were detected as metal impurities in the eluent, but both were ≤10 μg/GBq. The endotoxin concentration of the eluate was ≤5 EU/mL, and the eluent passed the sterility test. These results show that the generator can stably provide ⁶⁸Ga solution over a 15-month period.

¹³¹I-3-iodobenzylguanidine or ¹³¹I-iobenguane (3-(¹³¹I) iodobenzylguanidine or ¹³¹I-iobenguane [¹³¹I-MIBG]) is a radioactive agent that is specifically accumulated in tumor cells such as pheochromocytoma and neuroblastoma. Due to its cytotoxic beta ray emitted from ¹³¹I, it has been developed as an agent for radioisotope therapy and some researchers have reported its effectiveness. In this study, based on the patients’ data from previous clinical trials of ¹³¹I-MIBG therapy, we evaluated the radiation safety for public exposure caused by radiation emitted from patients who received ¹³¹I-MIBG. In results, it was considered that public exposure and medical exposure of visitors and caregivers to the patients were less than their dose limit and dose constraint by complying the current criteria of the release of patients after therapy with ¹³¹I.

This survey was performed in order to investigate the incidence of adverse reactions to radiopharmaceuticals in FY2019 in Japan. It was based on responses to questionnaires sent to nuclear medicine institutions. Replies were obtained from 1,003 institutions out of 1,213 to which the questionnaire had been sent. A total of 1,037,568 radiopharmaceutical administrations were reported. Eighteen cases of adverse reactions were reported. The incidence of adverse reactions per 100,000 cases was 1.7. No case of defective products was reported.