Predicting the Prognosis of Prostate Cancer Bone Metastasis Using the Bone Scan Index and Hot Spots Calculated Using VSBONEⓇ Bone Scan Index from Tc-99m-Hydroxymethylene Diphosphonate Bone Scintigraphy.

INTRODUCTION: The bone scan index (BSI) is widely used as a quantitative indicator of bone metastasis, therapeutic effect assessment, and prognosis prediction in prostate cancer. However, the BONE NAVI, which calculates BSI, only supports bone scintigraphy using Tc-99m-methylene diphosphonate. We developed the VSBONEⓇ BSI, which calculates BSI from bone scintigraphy using Tc-99m-hydroxymethylene diphosphonate (HMDP). The purpose of this study was to demonstrate that the BSI calculated using VSBONEⓇ BSI and hot spots (HS), which indicates the number of abnormal accumulations, are useful prognostic factors for patients with prostate cancer bone metastasis, similar to BONE NAVI. METHODS: We analyzed 322 patients who underwent bone scintigraphy for prostate cancer bone metastasis at our hospital. Initial bone scintigraphy was performed using Tc-99m-HMDP. All cases were retrospectively examined for their outcome and time to the final outcome. The results obtained were compared with the BSI and HS calculated using VSBONEⓇ BSI. RESULTS: When the patients were divided into two groups, HS >2 and HS ≤2, the HS ≤2 group had a significantly longer survival time (p < 0.001). In addition, when divided into two groups, BSI >0.46 and BSI ≤0.46, the survival time of the BSI ≦0.46 group was significantly longer (p < 0.001). CONCLUSION: BSI and HS obtained using VSBONEⓇ BSI may be useful as prognostic predictors, similar to those obtained using BONE NAVI.

Evaluation of ablation of thyroid remnants with 1850 MBq iodine-131 in 67 patients with thyroid cancer.

BACKGROUND: Radioiodine remnant ablation (RRA) is used to destroy residual normal thyroid tissue after total thyroidectomy in differentiated thyroid carcinoma (DTC) patients. As 1850-MBq RRA is routinely performed at our facility, we evaluated the outcomes. METHODS: Sixty-seven DTC patients without macroscopic residual lesions after total thyroidectomy were evaluated. Thyroglobulin (Tg) was measured 2-3 months before RRA with thyroxin administration (pretreatment); just before ablation after a 3-week iodine intake restriction with thyroxin withdrawal (THW) (N.=16) or recombinant human thyroid-stimulating hormone (rhTSH) stimulation (N.=51); and 3 months after RRA, after a 2-week iodine intake restriction and 3-week THW (N.=57) or rhTSH stimulation (N.=10). All patients received 131I (1850 MBq) treatment followed by 131I scintigraphy about 8 days later (8.18±0.91) and 131I scintigraphy (185 MBq) after the dosage 24 hours later 3months after RRA. Initial RRA goal was defined as negatively visible uptake in 131I thyroid bed (VUT) and a Tg level of <2 ng/mL 3 months after RRA. RESULTS: Rest 60 patients whose TSH levels were below 0.5 µIU/mL of all 67 patients were evaluated. Negatively VUT on 3 months after RRA was shown in 56 out of 60 patients (93.3%). Initial RRA goal was achieved in 21 (42.0%) of 50 patients, excluding 3 patients whose Tg levels 3 months after RRA were not measured and 7 patients with anti-Tg antibodies. Pretreatment Tg levels (P=0.0003) was significant predictive factor for Initial RRA goal on multivariate logistic regression analysis. CONCLUSIONS: RRA with 1850 MBq is effective by visual diagnosis, about 40% of all intermediate or high-risk DTC patients achieved initial RRA goals by both visual and Tg levels diagnosis.

[Using Super Resolution to Denoise on PET Images].

A high-resolution display panel comes to practical use, but the resolution of the indicated contents does not change. The up-sampling processing is applied to indication of the low-resolution contents. In the up-sampling process, the super resolution enables an up-sampling process which estimates information of high frequency components lost by sampling while analyzing input images is noticed. In this paper, we aimed at reconstructing an image of normal resolution in which the influence of statistical noise is reduced by applying super resolution after down-sampling processing is applied to positron emission tomography (PET) image with many statistical noises. To evaluate the noise reduction effect, we compared it with the Gaussian filter which is frequently used to reduce the influence of the statistical noise of the PET image. A 3D Hoffman brain phantom was used to evaluate objectively by peak signal-to-noise ratio and power spectral density. The objective index of the PET image applying super resolution is positive results, suggesting the possibility of being useful as compared with the conventional method.

Scatter Correction of Septal Penetration for 123I-IMP Cerebral Blood Flow SPECT Adding Radioactivity from the Outside of Field of View-Comparison between Simulation-based and Multi-window Scatter Corrections.

PURPOSE: The N-Isopropyl-p-[123I] Iodoamphetamine (123I-IMP) SPECT imaging reduces the image quality and quantitative accuracy due to scatter and septal penetration occurred by radioactive uptake from outside of the field of view such as the lungs. We evaluated the influence of scatter and septal penetration using phantom-simulated radioactivity from outside of the field of view, and subsequently compared the effect of scatter and septal penetration corrections between the simulation-based effective scatter source estimation (ESSE) method and the multi-window method (ellipse approximation method). METHODS: We used the phantom filled with 10 and 25 kBq/mL for the brain and lung parts corresponding to radioactive concentration in the clinical study. The SPECT images were acquired with and without lung phantom using low-energy high-resolution (LEHR) and cardiac high-resolution (CHR) collimators. We quantitatively evaluated a brain phantom by count analysis and coefficient of variation as reference data without lung phantom simulated the radioactivity from outside of the field of view, and compared between two scatter corrections by each collimator. RESULTS: The brain count in cerebral base with the ESSE method using LEHR collimator was higher than that of the ellipse approximation method. The whole brain count with the ellipse approximation method using CHR collimator shows 28.8% lower than the ESSE method, so that it suggests that the ellipse approximation method for LEHR collimator and the ESSE method for CHR collimator was close to reference counts. The coefficient of variation of the ESSE method was lower than that of the ellipse approximation method for both two collimators. CONCLUSIONS: It was possible to correct the scatter and penetration from outside the field of view with high accuracy, by using the ellipse approximation method with LEHR collimator and the ESSE method with CHR collimator.

Parahippocampal Atrophy is Associated with Depressive Symptoms in Alzheimer's Disease.

Background Alzheimer's disease (AD) patients frequently show depressive symptoms, yet the pathological background remains unclear. The voxel-based specific regional analysis system for AD (VSRAD) allows quantification of atrophy in the medial temporal structures. We measured the degree of parahippocampal atrophy in AD patients using VSRAD, and investigated the association between imaging analysis results and the severity of depressive symptoms. Methods Brain magnetic resonance imaging (MRI) was conducted in 39 AD outpatients, and all MRI data were analyzed using VSRAD. The target region of interest (ROI) mainly consisted of the parahippocampal gyrus. The degree of atrophy in the ROI was obtained from the averaged positive z score (Z-score) of the ROT. AD patients were divided into two groups based on the severity of their depressive symptoms using the Geriatric Depression Scale (GDS), the depressive group (D group: 20 patients) and non- depressive group (ND group: 19 patients), and the clinical characteristics and VSRAD results of both groups were compared. Results There were no significant differences in demographics or cognitive function between the two groups. The Z-scores of the D group were significantly higher than those of the ND group (p<0.05). Additionally, there was a significant positive correlation between the GDS score and Z-scores in the parahippocampal gyrus. Conclusions Our findings suggested that the severity of depressive symptoms is associated with the severity of parahippocampal atrophy in AD patients.

[Imaging of hyperparathyroidism-Ultrasonography and 99mTc-MIBI scintigraphy-].

Treatments for primary hyperparathyroidism due to adenoma, hyperplasia and carcinoma and secondary hyperparathyroidism are mainly surgical resections of them. Accurate imaging diagnoses of the existences and the regions are very important for reductions of invasiveness. We describe ultrasonography and (99m)Tc-MIBI scintigraphy of hyperparathyroidism. We explain an advantage, a disadvantage and diagnosability of these modalities. We mention utilities of SPECT/CT, too. We show echogram and (99m)Tc-MIBI scintigraphy images about 3 cases of hyperparathyroidism.

The Relationship Between Medial Temporal Lobe Atrophy and Cognitive Impairment in Patients With Dementia With Lewy Bodies.

BACKGROUND: The relationship between medial temporal lobe atrophy (MTA) and cognitive impairment in patients with dementia with Lewy bodies (DLB) remains unclear. We examined this relationship using voxel-based specific regional analysis system for Alzheimer disease (VSRAD) advance software, which allowed us to quantify the degree of MTA on images obtained from magnetic resonance imaging (MRI) scans. METHODS: Thirty-seven patients diagnosed with DLB were recruited and scanned with a 1.5 Tesla MRI scanner. All MRI data were analyzed using VSRAD advance. The target volume of interest (VOI) included the entire region of the entorhinal cortex, hippocampus, and amygdala. The degree of MTA was obtained from the averaged positive z-score (Z score) on the target VOI, with higher scores indicating more severe MTA. Mini-Mental State Examination (MMSE) and the Revised Hasegawa Dementia Scale (HDS-R), which strengthened the measures of memory and language more than MMSE, were used to assess the presence of cognitive impairment. RESULTS: A negative correlation was found between the Z score and MMSE total scores or the HDS-R total scores. A stepwise multiple regression analysis performed to adjust the covariate effects of sex, age, the onset age of the disease, duration of DLB, years of education, and donepezil treatment showed that the HDS-R total scores were independently associated with the Z score, whereas MMSE total scores were not. CONCLUSIONS: These results suggest that MTA is related to cognitive impairment in patients with DLB, particularly the regions of orientation, immediate and delayed recall, and word fluency.

Role of per-rectal portal scintigraphy in long-term follow-up of congenital portosystemic shunt.

BACKGROUND: Congenital portosystemic shunt (CPSS) has the potential to cause hepatic encephalopathy and thus needs long-term follow-up, but an effective follow-up method has not yet been established. We aimed to evaluate the importance of per-rectal portal scintigraphy (PRPS) for long-term follow-up of CPSS. METHODS: We retrospectively examined shunt severity time course in patients (median: 9.6 y, range: 5.2-16.6 y) with intrahepatic (n = 3) or extrahepatic (n = 3) CPSS by using blood tests, ultrasonography or computed tomography, and PRPS. Per-rectal portal shunt index (cutoff: 10%) was calculated by PRPS. RESULTS: PRPS demonstrated that the initial shunt index was reduced in all intrahepatic cases (from 39.7 ± 9.8% (mean ± SD) to 14.6 ± 4.7%) and all extrahepatic cases (from 46.2 ± 10.9 to 27.5 ± 12.6%) during the follow-up period. However, ultrasonography and computed tomography disclosed different shunt diameter time courses between intrahepatic and extrahepatic CPSSs. Initial shunt diameter (5.8 ± 3.5 mm) reduced to 2.0 ± 0.3 mm in intrahepatic cases, but the initial diameter (6.3 ± 0.7 mm) increased to 10.6 ± 1.0 mm in extrahepatic cases. All patients had elevated serum total bile acid or ammonia levels at initial screening, but these blood parameters were insufficient to assess shunt severity because the values fluctuate. CONCLUSION: PRPS can track changes in the shunt severity of CPSS and is more reliable than ultrasonography and computed tomography in patients with extrahepatic CPSS.

Diagnostic ability of (99m)Tc-HSA-DTPA scintigraphy in combination with SPECT/CT for gastrointestinal bleeding.

PURPOSE: Gastrointestinal (GI) bleeding scintigraphy in combination with single-photon emission computed tomography/computed tomography (SPECT/CT) remains to be studied in detail. This study aimed to examine the diagnostic ability of this tool. METHODS: GI bleeding scintigraphy using (99m)Tc-human serum albumin-diethylenetriaminepentaacetic acid was performed for 38 patients with suspected GI bleeding. Twenty-four patients were diagnosed using planar images alone (planar group) and 14 patients were diagnosed using planar images and additional SPECT/CT images (planar + SPECT/CT group). The diagnostic ability of each method was analyzed. RESULTS: GI bleeding was observed in 20 of the 38 patients. For the existence of GI bleeding, planar images alone showed a sensitivity of 70%, specificity of 93%, positive predictive value (PPV) of 88%, negative predictive value (NPV) of 81%, and an overall accuracy of 83%, whereas planar images + SPECT/CT showed a sensitivity of 100%, specificity of 75%, PPV of 91%, NPV of 100%, and an overall accuracy of 93%. The source of bleeding was accurately diagnosed in 50% in the planar group and 78% in the planar + SPECT/CT group. In the planar + SPECT/CT group, 44% of the evaluable patients showed correct localization of the source of GI bleeding by additional SPECT/CT images, although planar images only showed incorrect localization. CONCLUSION: GI bleeding scintigraphy in combination with SPECT/CT is a noninvasive and useful tool for the examination of GI bleeding.

Strategy of operative treatment of hyperparathyroidism using US scan and (99m)Tc-MIBI SPECT/CT.

We evaluated the efficacy of technetium-sestamibi ((99m) Tc-MIBI) SPECT/CT for planning parathyroidectomy in cases with primary hyperparathyroidism (pHPT), comparing with planar scintigraphy and ultrasound (US), in an aim to establish the proper surgical strategy according to the preoperative imaging studies. A retrospective review of consecutive 75 pHPT patients who had been operated on was conducted. The results of preoperative imaging modalities and the operative finding were analyzed. Seven cases were found to have multiple hyperplastic glands, and no responsible gland was found in three cases. Four cases underwent only US scan for preoperative imaging. Remaining 61 cases were found to have single adenoma, and were included in the evaluation of localization imaging. US scan, (99m) Tc-MIBI planar scan and (99m) Tc-MIBI SPECT/CT showed accurate localization in 77.0% (47/61), 75.4% (46/61) and 88.5% (46/52) of the evaluable cases, respectively. US and (99m) Tc-MIBI planar scan demonstrated consistent result in 42 cases (68.9%), and those cases showed accurate localization in 90.5% (38/42). When both US and (99m) Tc-MIBI SPECT/CT was consistent, all 37 lesions had been correctly indicated. No clinico-pathological features were suggested to influence in demonstrating the localization, other than only (99m) Tc-MIBI SPECT/CT exhibited 100% sensitivity in ectopic glands. Combination of US and (99m) Tc-MIBI SPECT/CT certainly contributes to the planning of minimally invasive operation in cases with pHPT by indicating correct localization of single adenoma.

Correlation between right medial temporal lobe atrophy and persecutory delusions in patients with dementia of the Alzheimer's type demonstrated on VSRAD advance.

BACKGROUND: The relationship between focal brain atrophy and delusions in patients with Dementia of the Alzheimer's Type (DAT) is not well understood. Few studies have been reported on the association between medial temporal atrophy (MTA) and persecutory delusions in patients with DAT. We investigated the relationship between MTA and persecutory delusions in patients with DAT using voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) advance software, which allows us to quantify the laterality and the degree of MTA on magnetic resonance imaging (MRI) scans. METHODS: Thirty-one patients diagnosed with DAT were recruited and scanned with a 1.5 tesla MRI scanner. All MRI data were analyzed using VSRAD advance. The target volume of interest (VOI) included the entire region of the entorhinal cortex, hippocampus, and amygdala. The degree of MTA was obtained from the averaged positive z score (Z-score) on the target VOI, with higher scores indicating more severe. These DAT patients were divided into a group with (D group: n = 13) and without (ND group: n = 18) persecutory delusions. RESULTS: In the D group, the mean the bilateral, right, and left Z-scores were 2.45, 2.69, and 2.19, respectively. These mean Z-scores of the ND group were 2.00, 2.00, and 1.95, respectively. The right Z-scores for the D group were significantly higher than those for the ND group (p < 0.05). CONCLUSIONS: These findings suggest that right MTA could contribute to the development of persecutory delusions in patients with DAT.

[Clinical nuclear medicine in bone metastases].

(99m)Tc-hydroxymethylene diphosphonate is not directly to Calcium of the bone matrix, but is binding to hydroxyapatite within the bone matrix. Strontium-89 is a member of family II A of the periodic table, same as Calcium, and is incorporated into bone matrix directly. It is very important that the the regions of the pain from bone metastases are present in the site of the abnormal uptake by bone metastases.

[Bilateral filter applied to bone scintigraphy].

The aim of this study is to improve the image quality using a post process rather than a correction process at acquisition time. We used a smoothing filter that is widely used on a compact digital camera. Especially for nuclear medicine, when we use a short acquisition time, we will get images that have a large increase in statistical noise. For those images, we validated the efficiency of the smoothing filter by assessing two characteristic parameters. In addition, we defined the best smoothing filter parameters to get stable images that reduced the influence of statistical noise.

Short-term hepatocyte function and portal hypertension outcomes of sofosbuvir/velpatasvir for decompensated hepatitis C-related cirrhosis.

BACKGROUND: It is unclear whether hepatocyte function and/or portal hypertension improves if a sustained virologic response (SVR) is achieved with direct-acting antivirals in patients with decompensated hepatitis C-related cirrhosis. METHODS: We examined the safety and efficacy of a 12-week course of sofosbuvir/velpatasvir (SOF/VEL) in 20 patients with decompensated hepatitis C-related cirrhosis. We also investigated changes in the hepatocyte receptor index (LHL15) and blood clearance index (HH15) by Tc-99 m-galactosyl human serum albumin scintigraphy, liver stiffness measurement (LSM) by transient elastography, and hepatic venous pressure gradient (HVPG) in patients who achieved an SVR at 24 weeks after treatment (SVR24). RESULTS: One patient discontinued treatment because of rectal variceal hemorrhage, and 19 patients completed treatment. SVR24 was achieved in 17 patients (89%). Median LHL15 increased from 0.72 pre-treatment to 0.82 after SVR24 (p = 0.012), and median HH15 decreased from 0.82 pre-treatment to 0.76 after SVR24 (p = 0.010). The percentage of patients with LSM ≥ 20 kPa was 90% before treatment and remained at 90% after SVR24. However, the percentage with severe portal hypertension (defined as HVPG ≥ 12 mmHg) decreased from 92% pre-treatment to 58% after SVR24 (p = 0.046). Patients with a decreased HVPG from pre-treatment to after SVR24 had a smaller pre-treatment spleen volume than those with an increased HVPG (median, 252 vs. 537 mL, p = 0.028). CONCLUSION: Achieving SVR24 with SOF/VEL treatment in patients with decompensated hepatitis C-related cirrhosis can be expected to improve hepatocyte function and portal hypertension on short-term follow-up.

Deep learning-based detection of parathyroid adenoma by 99mTc-MIBI scintigraphy in patients with primary hyperparathyroidism.

OBJECTIVE: It is important to detect parathyroid adenomas by parathyroid scintigraphy with 99m-technetium sestamibi (99mTc-MIBI) before surgery. This study aimed to develop and validate deep learning (DL)-based models to detect parathyroid adenoma in patients with primary hyperparathyroidism, from parathyroid scintigrams with 99mTc-MIBI. METHODS: DL-based models for detecting parathyroid adenoma in early- and late-phase parathyroid scintigrams were, respectively, developed and evaluated. The training dataset used to train the models was collected from 192 patients (165 adenoma cases, mean age: 64 years ± 13, 145 women) and the validation dataset used to tune the models was collected from 45 patients (30 adenoma cases, mean age: 67 years ± 12, 37 women). The images were collected from patients who were pathologically diagnosed with parathyroid adenomas or in whom no lesions could be detected by either parathyroid scintigraphy or ultrasonography at our institution from June 2010 to March 2019. The models were tested on a dataset collected from 44 patients (30 adenoma cases, mean age: 67 years ± 12, 38 women) who took scintigraphy from April 2019 to March 2020. The models' lesion-based sensitivity and mean false positive indications per image (mFPI) were assessed with the test dataset. RESULTS: The sensitivity was 82% [95% confidence interval 72-92%] with mFPI of 0.44 for the scintigrams of the early-phase model and 83% [73-92%] with mFPI of 0.31 for the scintigrams of the delayed-phase model in the test dataset, respectively. CONCLUSIONS: The DL-based models were able to detect parathyroid adenomas with a high sensitivity using parathyroid scintigraphy with 99m-technetium sestamibi.

[Development of Dose Management Software Using Visual Basic for Applications and Dose Evaluation in the Field of Nuclear Medicine].

PURPOSE: The purpose of this study was to develop software for smooth dose management based on the Japan diagnostic reference levels (DRLs 2020) in the field of nuclear medicine. METHOD: Using the programming language Visual Basic for Applications (VBA), we implemented a function for calculating actual doses, a function for comparing doses at one's own facility with those of DRLs 2020, a function for calculating appropriate doses for pediatric nuclear medicine examinations, and so on. In addition, we evaluated actual doses before and after the software implementation. RESULT: The software enabled easy calculation of actual doses and comparison with DRLs 2020 for smooth dose management. Furthermore, we were able to use the results of dose evaluation to determine the dosage at our facility and to use them as a reference for optimization. CONCLUSION: In the field of nuclear medicine, it is possible to manage doses in accordance with DRLs 2020 by introducing own software into our clinical practice.

Evaluation of therapeutic response to donepezil by positron emission tomography.

BACKGROUND: Donepezil hydrochloride (Donepezil) is an acetylcholinesterase inhibitor (AChEI) that is used for the symptomatic treatment of Dementia of the Alzheimer's Type (DAT). Recently, the effects of AChEI in patients with DAT have been investigated using positron emission tomography (PET) or single photon emission computed tomography (SPECT). This study is to evaluate the usefulness of fluorine-18-fluorodeoxyglucose (FDG)-PET in assessing the therapeutic response of Donepezil to DAT using Regions of Interest (ROI) analysis. METHODS: The participants included eleven outpatients diagnosed as having DAT according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The patients were performed FDG-PET before initiating Donepezil therapy and after 12 weeks of medication. Cognitive change was measured using the Japanese version of the Alzheimer's disease Assessment Scale cognitive subscale (ADAS-J cog) and the group was divided into Responders and Non-responders based on these results. We used FDG-PET to investigate glucose metabolism of the brain and measured FDG uptake in the ROI set in each lobe of the brain. Then the ratios of the post-treatment uptake to pre-treatment uptake were determined. RESULTS: In the Responders, the mean ratios in the frontal, temporal, occipital, parietal, and temporoparietal lobes were 2.18, 1.62, 1.15, 1.12, and 1.09 respectively. The mean ratios of the Non-responders were 0.69, 0.88, 0.75, 0.98, and 0.68 respectively. Significant differences were found between the ratios of the Responders and Non-responders in the frontal and occipital lobes (p < 0.05). CONCLUSIONS: These findings suggest that FDG-PET could be useful for the evaluation for monitoring response to Donepezil.

Study of the Usefulness of Bone Scan Index Calculated From 99m-Technetium- Hydroxymethylene Diphosphonate (99mTc-HMDP) Bone Scintigraphy for Bone Metastases from Prostate Cancer Using Deep Learning Algorithms.

BACKGROUND: BSI calculated from bone scintigraphy using 99mtechnetium-methylene diphosphonate (99mTc-MDP) is used as a quantitative indicator of metastatic bone involvement in bone metastasis diagnosis, therapeutic effect assessment, and prognosis prediction. However, the BONE NAVI, which calculates BSI, only supports bone scintigraphy using 99mTc-MDP. AIMS: We developed a method in collaboration with the Tokyo University of Agriculture and Technology to calculate bone scan index (BSI) employing deep learning algorithms with bone scintigraphy images using 99mtechnetium-hydroxymethylene diphosphonate (99mTc-HMDP). We used a convolutional neural network (CNN), enabling the simultaneous processing of anterior and posterior bone scintigraphy images named CNNapis. OBJECTIVES: The purpose of this study is to investigate the usefulness of the BSI calculated by CNNapis as bone imaging and bone metabolic biomarkers in patients with bone metastases from prostate cancer. METHODS: At our hospital, 121 bone scintigraphy scans using 99mTc-HMDP were performed and analyzed to examine bone metastases from prostate cancer, revealing the abnormal accumulation of radioisotope (RI) at bone metastasis sites. Blood tests for serum prostate-specific antigen (PSA) and alkaline phosphatase (ALP) were performed concurrently. BSI values calculated by CNNapis were used to quantify the metastatic bone tumor involvement. Correlations between BSI and PSA and between BSI and ALP were calculated. Subjects were divided into four groups by BSI values (Group 1, 0 to <1; Group 2, 1 to <3; Group 3, 3 to <10; Group 4, >10), and the PSA and ALP values in each group were statistically compared. RESULTS: Patients diagnosed with bone metastases after bone scintigraphy were also diagnosed with bone metastases using CNNapis. BSI corresponding to the range of abnormal RI accumulation was calculated. PSA and BSI (r = 0.2791) and ALP and BSI (r = 0.6814) correlated positively. Significant intergroup differences in PSA between Groups 1 and 2, Groups 1 and 4, Groups 2 and 3, and Groups 3 and 4 and in ALP between Groups 1 and 4, Groups 2 and 4, and Groups 3 and 4 were found. CONCLUSION: BSI calculated using CNNapis correlated with ALP and PSA values and is useful as bone imaging and bone metabolic biomarkers, indicative of the activity and spread of bone metastases from prostate cancer.

Assessment of a software for semi-automatically calculating the bone scan index on bone scintigraphy scans.

AIMS: The incidence of bone metastases exceeds 85% in patients who die from prostate cancer. Bone scintigraphy is the most widely used method for the early detection of bone metastases in prostate cancer. We developed a software program that semi-automatically calculated the bone scan index (BSI) on technetium-99m hydroxymethylene diphosphonate bone scintigraphy scans with a computer-aided diagnosis system (CAD) and examined whether the BSI calculated using this software could replace the extent of disease (EOD) score. METHODS: The subjects were 175 patients who were diagnosed with prostate cancer at our hospital and underwent bone scintigraphy. We analyzed receiver operating characteristic curves to determine the BSI cutoff value between EOD groups. The cutoff value was determined based on the maximum value of the sum of the sensitivity and specificity. RESULTS: BSI cutoff values of 0.20, 1.56, and 4.56 were used to distinguish between EOD 0 and 1-4 (sensitivity [87.2%] and specificity [100.0%]), between EOD 0- and 2-4 (sensitivity [85.2%] and specificity [92.0%]), and between EOD 0-2 and 3-4 (sensitivity [88.4%] and specificity [99.2%]), respectively. CONCLUSION: Our results suggest that this software can calculate BSI, and the software may play a role in predicting prognosis and selecting an appropriate treatment strategy. If a sufficient number of other nuclear medicine tests are performed, creating a similar CAD system is possible.

Extraction of metastasis hotspots in a whole-body bone scintigram based on bilateral asymmetry.

PURPOSE: A hotspot of bone metastatic lesion in a whole-body bone scintigram is often observed as left-right asymmetry. The purpose of this study is to present a network to evaluate bilateral difference of a whole-body bone scintigram, and to subsequently integrate it with our previous network that extracts the hotspot from a pair of anterior and posterior images. METHODS: Input of the proposed network is a pair of scintigrams that are the original one and the flipped version with respect to body axis. The paired scintigrams are processed by a butterfly-type network (BtrflyNet). Subsequently, the output of the network is combined with the output of another BtrflyNet for a pair of anterior and posterior scintigrams by employing a convolutional layer optimized using training images. RESULTS: We evaluated the performance of the combined networks, which comprised two BtrflyNets followed by a convolutional layer for integration, in terms of accuracy of hotspot extraction using 1330 bone scintigrams of 665 patients with prostate cancer. A threefold cross-validation experiment showed that the number of false positive regions was reduced from 4.30 to 2.13 for anterior and 4.71 to 2.62 for posterior scintigrams on average compared with our previous model. CONCLUSIONS: This study presented a network for hotspot extraction of bone metastatic lesion that evaluates bilateral difference of a whole-body bone scintigram. When combining the network with the previous network that extracts the hotspot from a pair of anterior and posterior scintigrams, the false positives were reduced by nearly half compared to our previous model.