Nuclear medicine practice in Japan: a report of the ninth nationwide survey in 2022.

Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to survey contemporary nuclear medicine practice and its changes over the years. The subcommittee sent questionnaires, including the number and category of examinations as well as the kind of the radiopharmaceuticals during the 30 days of June 2022 to all nuclear medicine institutes in Japan. The total numbers of them for the year 2022 were estimated depends on the 1-month data. A total of 1095 institutes responded to the survey, including 364 positron emission tomography (PET) centers. The recovery rate was 90.6%. The number of gamma cameras installed was 1299 in total, with 2.5% decrease in 5 years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 83.8% and 35.5%, respectively. The number of single-photon tracer studies in 2022 was 1.11 million which means increase in 2.7% in 5 years. Bone scintigraphy was a leading examination (31.0%), followed by myocardial scintigraphy (27.1%) and cerebral perfusion study (23.8%) in order. The percentage of SPECT studies showed an increase from 63.5% in previous survey to 66.8% in this survey. PET centers have also increased from 389 to 412, as compared with the previous one. One hundred and twenty-two PET centers have installed one or two in-house cyclotrons. Increasing trends of the PET studies were observed from 1992 to 2017, the trend changed and PET studies showed 1.5% decrease in 5 years. 18F-FDG accounted for 98.6% (610,497 examinations). PET examinations using 11C-methionine, 13N-NH3 and 11C-PIB have decreased, with 1624, 2146 and 525 examinations, respectively in 2022. The total number of nuclear medicine examination was eventually increased by 1.0%. Therapies for pheochromocytoma or paraganglioma (PPGL) with 131I-MIBG and for neuroendocrine tumor with 177Lu-DOTA-TATE were newly started, however, a total number of targeted radionuclide therapy was decreased by 17.7% because 131I-radioiodine and 223Ra targeted therapies were decreased and supply of some radioisotopes was discontinued. 131I-radioiodine targeted therapy showed a decrease in 5 years (- 15.9%), including 4099 patients for thyroid cancer. The number of out-patient thyroid bed ablation therapy with 1110 MBq of 131I was also decreased to 1015 per year. The number of admission rooms specialized for radionuclide targeted therapy increased from 157 to 160. The number of 223Ra targeted therapies for castration-resistant metastatic prostate cancer (mCRPC) was 1041 patients. This survey was performed during COVID-19 pandemic, however, total number of nuclear medicine examinations was almost same as previous survey (+ 1.0%). Radionuclide therapies with 131I-MIBG and 177Lu-DOTA-TATE were newly started, and new radionuclide therapy will be available in future, therefore, the development of radionuclide therapy will be continued. We are convinced that this survey report is useful in understanding the current status of the nuclear medicine practice in Japan, and in devising the new strategy to strengthen a role of nuclear medicine.

Inter- and intra-rater reproducibility of quantitative T1 measurement using semiautomatic region of interest placement in myometrium.

PURPOSE: This study aimed to investigate the inter- and intraobserver reproducibility of quantitative T1 (qT1) measurements using manual and semiautomatic region of interest (ROI) placements. We hypothesized the usefulness of the semiautomatic method, which utilizes a three-dimensional (3D) anatomical relationship between the myometrium and other tissues, for minimizing ROI placement variation, thereby improving qT1 reproducibility compared to the manual approach. The semiautomatic approach, which considered anatomical relationships, was expected to enhance reproducibility by reducing ROI placement variabilities. MATERIALS AND METHODS: This study recruited 23 healthy female volunteers. Data with variable flip angle (VFA) and inversion recovery were acquired using 3D-spoiled gradient echo and spin echo sequences, respectively. T1 maps were generated with VFA. Manual and semiautomatic ROI placements were independently conducted. Mean qT1 values were calculated from the T1 maps using the corresponding pixel values of the myometrial ROI. Inter- and intraobserver reproducibility of qT1 values was investigated. The inter- and intraobserver reproducibility of qT1 values was evaluated by calculating the coefficient of variation (CoV). Further, reproducibility was evaluated with inter- and intraobserver errors and intraclass correlation coefficients (ICCs). Bland-Altman analysis was utilized to compare the results, estimate bias, and determine the limits of agreement. RESULTS: The mean inter- and intraobserver CoV of the qT1 values for semiautomatic ROI placement was significantly lower than those for manual ROI placement (p < 0.05 and p < 0.01, respectively). ICCs for semiautomatic ROI placement were greater than those for manual ROI placement. Further, the mean inter- and intraobserver errors for semiautomatic ROI placement were significantly lower than those for manual ROI placement (p < 0.05 and p < 0.01, respectively). CONCLUSION: Semiautomatic ROI placement demonstrated high reproducibility of qT1 measurements compared with manual methods. Semiautomatic ROI placement may be useful for evaluating uterine qT1 with high reproducibility.

Benefits of basil tea for patients with differentiated thyroid cancer during radioiodine therapy: A randomized controlled trial.

Background: Acute sialadenitis is one of the major physical complications of radioactive iodine therapy (RAIT) for differentiated thyroid cancer (DTC). It is considered necessary to pay attention to the psychological impact on the patient as well as the physical influence during RAIT. Objective: To find evidence of the benefits of Basil tea on the psychological and physical side effects of RAIT. Methods: Forty-four DTC patients after total thyroidectomy were randomly divided into Group A (Basil tea group, n = 22) and Group B (Control group, n = 22). Subjects in Group A drank 180 mL of Basil tea prepared from 2.0 g of Holy basil (Ocimum tenuiflorum Linn.) leaves after each meal for four days, starting on the day RAIT was performed. Those in Group B drank the same amount of distilled water after each meal for the same period as those in Group A. The State-Trait Anxiety Inventory (STAI) was used to assess anxiety, while the saliva component test, and salivary gland scintigraphy were used to assess the oral cavity. Results: The rate of change of the STAI score (both State Anxiety and Trait Anxiety) was significantly lower in Group A than in Group B (P < 0.05). The rates of change of cariogenic bacteria, ammonia, protein, and occult blood were significantly lower in Group A than in Group B (P < 0.05). The rate of change of the washout ratio for salivary gland scintigraphy was significantly lower in Group B than in Group A (P < 0.05). Conclusions: Basil tea consumption not only protected against oral mucosal conditions and salivary gland disorders but also significantly relieved the patient's RAIT-related anxiety. Therefore, it was suggested that this tea could be useful for the maintenance of patients' QOL during RAIT.

Comparison of pain-relieving effects by number of irradiations, through propensity score matching and the international consensus endpoint.

Background: Palliative radiotherapy for bone metastases utilizes various dose fractionation schedules. The pain-relieving effects of a single fraction (SF) and multiple fractions (MF) are largely debated due to the difficulty in matching patients' backgrounds and in assessing the effectiveness of pain relief. This study aimed to compare the pain-relieving effects of SF and MF palliative radiotherapy for bone metastases using propensity score matching and the international consensus endpoint (ICE). Materials and methods: Our study included 195 patients irradiated for bone metastasis. The primary endpoint was the pain-relieving effects used by ICE. In addition, the evaluation was performed by using responder (complete response/partial response) and non-responder (pain progression/indeterminate response) categorization. The secondary endpoints were the discharge or transfer rate at one month after irradiation and postirradiation pathological fracture rate. Propensity score matching was used to adjust patient's characteristics and reduce selection bias. Results: After adapting propensity score matching, the total number of patients was 74. There was no significant difference in the pain-relieving effects between SF and MF (p = 0.184). There were no significant differences in them between SF and MF when using responder and non-responder categorization (p = 0.163). Furthermore, there were no differences in the discharge or transfer rates (p = 0.693) and pathological fracture rates (p = 1.00). Conclusions: The combination of propensity score matching and ICE revealed no significant difference in the pain-relieving effects between SF and MF for bone metastases, thus, SF has no significant disadvantage compared to MF in pain-relieving effects.

Prognostic Implications of Sarcoidosis Granulomas　- Insights From the Multicenter Registry, the Japanese Cardiac Sarcoidosis Prognostic Study.

Background: Definitions of cardiac sarcoidosis (CS) differ among guidelines. Any systemic histological finding of CS is essential for the diagnosis of CS in the 2014 Heart Rhythm Society statement, but not necessary in the Japanese Circulation Society 2016 guidelines. This study aimed to reveal the differences in outcomes by comparing 2 groups, namely CS patients with or without systemic histologically proven granuloma. Methods and Results: This study retrospectively included 231 consecutive patients with CS. CS with granulomas in ≥1 organs was diagnosed in 131 patients (Group G), whereas CS without any granulomas was diagnosed in the remaining 100 patients (Group NG). Left ventricular ejection fraction (LVEF) was significantly reduced in Group NG compared with Group G (44±13% vs. 50±16%, respectively; P=0.001). However, Kaplan-Meier curves showed that major adverse cardiovascular events (MACE)-free survival outcomes were comparable between the 2 groups (log-rank P=0.167). Univariable analyses showed that significant predictors of MACE were Groups G/NG, histological CS, LVEF, and high B-type natriuretic peptide (BNP) or N-terminal pro BNP concentrations, but none of these was significant in multivariable analyses. Conclusions: Overall risks of MACE were similar between the 2 groups despite different manifestations in cardiac dysfunction. The data not only validate the prognostic value of non-invasive diagnosis of CS, but also show the need for careful observation and therapeutic strategy in patients with CS without any granuloma.

Effects of apitherapy against salivary gland disorder after radioactive iodine therapy for differentiated thyroid cancer.

OBJECTIVE: Sialadenitis and salivary gland disorders are complications of radioactive iodine therapy (RAIT) that affect the quality of life of patients with differentiated thyroid cancer (DTC). The current study aimed to provide evidence on the protective effect of apitherapy on salivary gland function during RAIT in patients with DTC. METHODS: In total, 120 patients with DTC who underwent total thyroidectomy were divided into the apitherapy group (group A, n = 60) and the control group (group B, n = 60). Group A received 2.5 g of acacia honey three times daily after each meal during admission for RAIT. Statistical analyses were performed using the Saxon test (which is used to evaluate saliva volume) and salivary gland scintigraphy (which is applied to assess maximum uptake ratio and washout ratio). RESULTS: Compared with group B, group A presented with a more significantly positive change in the rate of amount of saliva before and after treatment (P < 0.01). Group B presented a significant decrease in the maximum uptake ratio of the bilateral parotid and submandibular glands on salivary gland scintigraphy (P < 0.05) and washout ratio of all salivary glands (P < 0.05). Group A did not present significant differences in the maximum uptake ratio and washout ratio. CONCLUSIONS: Apitherapy can have protective effects against salivary gland disorder associated with RAIT in patients with DTC.

Interaction of impaired myocardial flow reserve and extent of myocardial ischemia assessed using 13N-ammonia positron emission tomography imaging on adverse cardiovascular outcomes.

BACKGROUND: Myocardial flow reserve (MFR) and the extent of myocardial ischemia identify patients at high risk of major adverse cardiovascular events (MACEs). Associations between positron emission tomography (PET)-assessed extent of ischemia, MFR, and MACEs is unclear. METHOD: Overall, 640 consecutive patients with suspected or known coronary artery disease undergoing 13N-ammonia myocardial perfusion PET were followed-up for MACEs. Patients were categorized into three groups based on myocardial ischemia severity: Group I (n = 335), minimal (myocardial ischemia < 5%); Group II (n = 150), mild (5-10%); and Group III (n = 155), moderate-to-severe (> 10%). RESULTS: Cardiovascular death and MACEs occurred in 17 (3%) and 93 (15%) patients, respectively. Following statistical adjustment for confounding factors, impaired MFR (global MFR < 2.0) was revealed as an independent predictor of MACEs in Groups I (hazard ratio [HR], 2.89; 95% confidence interval [CI], 1.48-5.64; P = 0.002) and II (HR, 3.40; 95% CI 1.37-8.41; P = 0.008) but was not significant in Group III (HR, 1.15; 95% CI 0.59-2.26; P = 0.67), with a significant interaction (P < 0.0001) between the extent of myocardial ischemia and MFR. CONCLUSION: Impaired MFR was significantly associated with increased risk of MACEs in patients with ≤ 10% myocardial ischemia but not with those having > 10% ischemia, allowing a clinically effective risk stratification.

Multicenter Registry in the Japanese Cardiac Sarcoidosis Prognostic (J-CASP) Study: Baseline Characteristics and Validation of the Non-invasive Approach Using 18F-FDG PET.

Background: Recent advances in cardiac modalities contribute to the guidelines on the diagnosis of cardiac sarcoidosis (CS) updated by the Japanese Circulation Society. The multicenter registry, Japanese Cardiac Sarcoidosis Prognostic (J-CASP) study tried to reveal recent trends of diagnosis and outcomes in CS patients and to validate the non-invasive diagnostic approach, including cardiac 18F-fluorodeoxyglucose (FDG) study. Methods/results: Databases from 12 hospitals consisting of 231 CS patients (mean age, 64 years; female, 65%; LV ejection fraction, 47%) diagnosed by the guidelines with FDG positron emission tomography (PET) study were integrated to compile clinical information on the diagnostic criteria and outcomes. Cardiac 18F-FDG uptake and magnetic resonance imaging (CMR) was positive identically in the histology-proven and clinically-diagnosed groups. The histology-proven group more frequently had reduce LV ejection fraction, myocardial perfusion abnormality and low-grade electrocardiogram (ECG) abnormality (P=0.003 to 0.016) than did the clinical group. During a 45-month period, the histology-proven group more frequently underwent appropriate implantable cardioverter-defibrillator (ICD) treatment (14% versus 4%, P=0.013) and new electronic device implantation (30% versus 12%, P=0.007) than did clinical group, respectively. There, however, was no difference in all-cause or cardiac mortality or in new hospitalization due to heart failure progression between them. Conclusion: The J-CASP registry demonstrated the rationale and clinical efficacies of non-invasive approach using advanced cardiac imaging modalities in the diagnosis of CS even when histological data were available.

Superficial myofibroblastoma of the vagina with a stalk: case report of a rare vaginal tumor with notable radiological findings.

Superficial myofibroblastoma is a rare benign mesenchymal tumor which predominantly occurs in the female lower genital tract. Here we present a case of a 42-year-old female patient with prolonged vaginal bleeding. Radiological imaging revealed a well circumscribed mass in the vagina with a stalk. The patient underwent surgery and the tumor was histologically diagnosed as superficial myofibroblastoma. Notably, this is the first report of the radiological imaging of a superficial myofibroblastoma harboring a stalk arising from the vaginal wall. We compared the radiological images with histological findings and discuss major differential diagnosis of vaginal tumors. Despite the challenging nature of preoperative diagnosis of mesenchymal vaginal tumors, radiological features may aid in differentiating them from other more aggressive entities or malignant tumors.

Dysostosis in mucopolysaccharidosis type 2: A case of longitudinal follow up and literature review.

Mucopolysaccharidosis type 2 is a congenital lysosomal disease characterized by iduronate-2-sulfatase deficiency, which leads to excessive accumulation of glycosaminoglycans in tissue. Dysostosis, which primarily involves decreased bone mineralization with morphological changes in the bone, is a major skeletal condition in mucopolysaccharidosis, but its pathophysiology is not well known. Here, we report a case of mucopolysaccharidosis type 2 diagnosed at the age of 2 years with longitudinal follow-up data for more than 15 years. Although the patient underwent bone marrow transplantation, the developmental quotient did not improve, and cranial hyperostosis progressed prominently with a faintly dilated perivascular space. Other dysostoses and contraction of the joints were observed but did not improve either.

The utility of a deep learning-based algorithm for bone scintigraphy in patient with prostate cancer.

OBJECTIVE: Bone scintigraphy has often been used to evaluate bone metastases. Its functionality is evident in detecting bone metastasis in patients with malignant tumor including prostate cancer, as appropriate treatment and prognosis are dependent on the presence and degree of bone metastasis. The development of a deep learning-based algorithm in the field of information processing has been remarkable in recent years. We hypothesized that a deep learning-based algorithm is useful in diagnosing osseous metastases in patients with prostate cancer using bone scintigraphy. Thus, this study aims to examine the utility of deep learning-based algorithm in detecting bone metastases in patients with prostate cancer, as compared with nuclear medicine specialists. METHODS: In total, 139 serial patients with prostate cancer, who underwent whole-body bone scintigraphy, were enrolled in this study. Each scintigraphy examination was evaluated visually and independently by nuclear medicine specialists; this was also analyzed using a deep learning-based algorithm. The number of abnormal uptakes was assessed by the nuclear medicine specialists and with a software which used the deep learning-based algorithm, and the per-patient detection rate and the per-region detection rate were then calculated. The software automatically analyzed bone scintigraphy for the presence or absence of osseous metastasis in individual patients, for the 12 body regions. The detection rates analyzed separately by the nuclear medicine specialists and using the software were then compared. The sensitivity, specificity, and accuracy by the specialist and with the software were calculated. RESULTS: The sensitivity, specificity, and accuracy by the nuclear medicine specialists were 100%, 94.9% and 97.1%. On the other hand, they with the software were 91.7%, 87.3% and 89.2%. No statistically significant difference was determined between the per-patient detection rates assessed by the specialists versus the software. In regional assessment, there was also no statistically significant difference between most of the per-region detection rates (10 of 12 regions) by the specialists versus the results obtained by the software. CONCLUSIONS: The software with the deep learning-based algorithm might be used as diagnostic aid in the evaluation of bone metastases for prostate cancer patients.

Noninvasive estimation of quantitative myocardial blood flow with Tc-99m MIBI by a compartment model analysis in rat.

BACKGROUND: We aimed to investigate the use of dynamic cardiac planar images to estimate myocardial blood flow (MBF) by a compartment model analysis using time-to-peak (TP) map and compared it by the microsphere technique in rat. Positron emission tomography is considered the gold standard method, but is not available everywhere. By contrast, although myocardial perfusion imaging (MPI) with single-photon tracers is more widely available, it may be difficult to obtain adequate region of interest (ROI) settings. We proposed using the TP map to set the ROI, and hypothesized that this method could facilitate the measurement of absolute MBF by MPI in rat. METHODS: Twenty-one normal rats were studied. Dynamic planar images with Tc-99m MIBI were obtained, and input function and cardiac ROIs were set using the obtained TP map. MBF was estimated by a one-compartment model analysis with the Renkin-Crone model and by the microsphere technique. RESULTS: The MBFs from these two methods were significantly correlated. A negative proportional bias was observed, but no significant difference was observed between the mean MBFs calculated with each method. CONCLUSIONS: MBF estimation by a compartment model analysis using TP map could facilitate absolute MBF measurement in rats.

Cerebrospinal fluid levels of alpha-synuclein, amyloid ß, tau, phosphorylated tau, and neuron-specific enolase in patients with Parkinson's disease, dementia with Lewy bodies or other neurological disorders: Their relationships with cognition and nuclear medicine imaging findings.

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are common neurodegenerative disorders, but no established biochemical markers for these diseases have been identified. We enrolled 78 subjects (27 patients with PD/DLB, 34 patients with non-PD/DLB neurodegenerative disorders [non-PD/DLB], and 17 controls). Cerebrospinal fluid (CSF) was collected via the standard lumbar puncture technique. The CSF levels of alpha-synuclein, amyloid ß40, amyloid ß42, tau, phosphorylated tau (p-tau), neuron-specific enolase (NSE), and hemoglobin were measured with enzyme-linked immunosorbent assays. Dopamine transporter imaging with 123I-ioflupane was also performed. The PD/DLB patients exhibited significantly lower CSF alpha-synuclein levels than non-PD/DLB group. Significantly elevated CSF levels of tau, p-tau, and NSE were detected in the non-PD/DLB group. Multivariate analysis revealed that the mini-mental state examination score was correlated with the CSF amyloid ß42 level. The specific binding ratio on 123I-ioflupane imaging was decreased in the PD/DLB group, but it was not correlated with the CSF alpha-synuclein level. These results indicate that (1) the CSF alpha-synuclein level is a useful biomarker of PD/DLB; (2) the CSF levels of tau, p-tau, and NSE can be used to discriminate PD/DLB from non-PD/DLB; and (3) the CSF amyloid ß42 level is an independent predictor of cognitive decline in neurological disorders.

An investigation of asymmetric reduction in dopamine transporter density in patients with Parkinson's disease.

Asymmetric motor symptoms and the contralateral side of dopaminergic deficits are commonly observed in patients with Parkinson's disease. The laterality of the specific binding ratio (SBR) for dopamine transporter single-photon emission computed tomography may be useful for estimation of reduced dopamine transporter density in striatum of patients with Parkinson's disease. SBR with Southampton method (S-SBR) is widely used to evaluate in our country, but the results occasionally contradict with that of motor symptoms or visual evaluation in clinical practice, thus preventing a confident diagnosis. We reported dopamine transporter evaluation with distance-weighted histogram (DWH). We hypothesized that the SBR calculated using DWH (DWH-SBR) may also be useful to evaluate the laterality. The purpose of this study was to investigate the laterality of the SBR versus the asymmetry of motor symptoms, and versus visual evaluation. In total, 100 adult patients with Parkinson's disease were enrolled in our study. The symptom-affected side, the visual-affected side, and the lower SBR side were evaluated. The evaluation was performed in a blinded manner. Correlations between the Hoehn and Yahr scale (HY scale) and both the SBRs were also investigated. Concordance of lower DWH-SBR side for visual-affected side was significantly higher (99.0%) than it of lower S-SBR side (86.0%, P < 0.01). The HY scale was significantly related to both lower S-SBR and DWH-SBR (P < 0.01). The DWH method might minimize the disagreement of laterality between the SBR and visual evaluation, and be useful for making a confident diagnosis in patients with Parkinson's disease.

Ninjurin 1 mediates peripheral nerve regeneration through Schwann cell maturation of NG2-positive cells.

Ninjurin 1 (Ninj1) is identified as a peripheral nerve injury-induced protein. However, the role of Ninj1 in nerve regeneration is unclear. Schwann cells (SCs) and microvasculature are critical for peripheral nerve regeneration. SCs precursors and microvascular pericytes (PCs), which are nerve/glial antigen 2 (NG2)-positive cells are observed in peripheral nervous system. In this study, we investigated the role of Ninj1 in peripheral nerve regeneration using NG2+cell-specific inducible deletion of Ninj1 mouse model. The number of NG2+cells, which were associated with and without microvessels was increased after sciatic nerve crush injury. There was a significant increase in the expression of Ninj1 and EphA7 in the injured nerve tissue. This increase was mostly observed in NG2+cells. Genetic tracing of NG2+cells was performed using tamoxifen (Tam) treatment on NG2CreERT:R26R-tdTomato mice. The sciatic nerve was injured following the Tam-treatment, then tdTomato-expressing SCs were mostly observed in regenerated SCs at 21 days after nerve injury. Ninj1 gene knockout (Ninj1 KO) in NG2+cells was induced using NG2CreERT:Ninj1loxp mice. Tam-treated-NG2CreERT or Tam-nontreated NG2CreERT:Ninj1loxp mice were used as controls. Following Tam-treatment, the sciatic nerve in each group was injured. Ninj1KO significantly attenuated the expression of the myelin binding protein (MBP) as well as the number of myelinated axons. The expression of MBP in cultured SCs was significantly reduced by SiRNA-mediated Ninj1 knockdown (KD). Ninj1KD also attenuated the differentiation of SCs by isolated EphA7+multipotent PCs. The current data indicate that Ninj1 plays a vital role in peripheral nerve regeneration. This is observed particularly in the myelination process of NG2+cells including SCs precursors and multipotent PCs.

Inter- and intra-observer reproducibility of quantitative analysis for FP-CIT SPECT in patients with DLB.

BACKGROUND: Dopamine transporter single photon emission CT (DAT-SPECT) is useful in the evaluation of dementia with Lewy bodies (DLB). The specific binding ratio (SBR) is an index to measure DAT density. However, poorly reproducible cases are occasionally experienced in clinical practice. We hypothesized that distance-weighted histogram (DWH) may be useful to improve the reproducibility of SBR. The purpose of this study was to investigate inter- and intra-observer reproducibility of SBR with conventional and DWH methods, and to visually evaluate the precision in reference voxel of interest (VOI) definition using these methods. METHODS: This study included 50 adult patients with probable DLB. They underwent brain MRI, DAT-SPECT, and cerebral blood flow SPECT with N-isopropyl-p-[123I]iodoamphetamine (I-123 IMP). SBR of the striatum was calculated using conventional and DWH method. For inter-observer reproducibility validation, conventional and DWH SBR were independently evaluated by experienced nuclear medicine physicians; these measurements were repeated by the nuclear medicine physician to investigate intra-observer reproducibility. RESULTS: Proper reference VOI definition was achieved in 60.0% using conventional SBR and in 98.0% with DWH SBR. Both conventional and DWH SBR demonstrated good inter- and intra-observer reproducibility, however, there were statistically significant inter- and intra-observer variations with conventional SBR measurements. Average inter- and intra-observer errors of conventional SBR were 7.9 and 6.1%, respectively. Conversely, DWH SBR errors were not observed in all patients. Moreover, average inter- and intra-observer errors were significantly higher in conventional SBR with improper reference VOI definition than in that with proper reference VOI definition. CONCLUSIONS: Although the reproducibility of conventional and DWH SBR was good, inter- and intra-observer bias could not be ignored in conventional SBR, particularly with improper reference VOI definition. Thus, DWH may be useful to improve inter- and intra-observer reproducibility of SBR.

Topics of nuclear medicine research in Europe.

Last year in the European Journal of Nuclear Medicine and Molecular Imaging, we introduced some recent nuclear medicine research conducted in Japan. This was favorably received by European readers in the main. This year we wish to focus on the Annals of Nuclear Medicine on some of the fine nuclear medicine research work executed in Europe recently. In the current review article, we take up five topics: prostate-specific membrane antigen imaging, recent advances in radionuclide therapy, [18F]fluorodeoxyglucose positron-emission tomography (PET) for dementia, quantitative PET assessment of myocardial perfusion, and iodine-124 (124I). Just at the most recent annual meeting of the European Association of Nuclear Medicine 2016, Kyoto was selected as the host city for the 2022 Congress of the World Federation of Nuclear Medicine and Biology. We hope that our continuous efforts to strengthen scientific cooperation between Europe and Japan will bring many European friends and a great success to the Kyoto meeting.

SUV navigator enables rapid [18F]-FDG PET/CT image interpretation compared with 2D ROI and 3D VOI evaluations.

PURPOSE: Positron emission tomography (PET) and the maximum standardized uptake value (SUVmax) is a useful technique for assessing malignant tumors. Measurements of SUVmax in multiple lesions per patient frequently require many time-consuming procedures. To address this issue, we designed a novel interface named SUV Navigator (SUVnavi), and the purpose of this study was to investigate its utility. MATERIALS AND METHODS: We measured SUVmax in 661 lesions from 100 patients with malignant tumors. Diagnoses and SUVmax measurements were made with SUVnavi, 2D, and 3D measurements. SUV measurement accuracy in each method were also evaluated. RESULTS: The average reduction in time with SUVnavi versus 2D was 53.8% and 3D was 37.5%; time required with SUVnavi was significantly shorter than with 2D and 3D (P < 0.001 and P < 0.001, respectively). The time reduction and lesion number had a positive correlation (P < 0.001 and P < 0.001, respectively). SUVmax agreed with precise SUVmax in all lesions measured with SUVnavi and 3D but in only 466 of 661 lesions (70.5%) measured with 2D. CONCLUSION: SUVnavi may be useful for rapid [18F]-fluorodeoxyglucose positron emission tomography/computed tomography ([18F]-FDG PET/CT) image interpretation without reducing the accuracy of SUVmax measurement.