Shingo Baba - Academia.edu (original) (raw)

Papers by Shingo Baba

Objective(s): In positron emission tomography (PET) studies, thoracic movement under free-breathi... more Objective(s): In positron emission tomography (PET) studies, thoracic movement under free-breathing conditions is a cause of image degradation. Respiratory gating (RG) is commonly used to solve this problem. Two different methods, i.e., phase-gating (PG) and amplitude-gating (AG) PET, are available for respiratory gating. It is important to know the strengths and weaknesses of both methods when selecting an RG method for a given patient. We conducted this study to clarify whether AG or PG is preferable for measuring fluorodeoxyglucose (FDG) accumulation in lung adenocarcinoma and to investigate patient conditions which are most suitable for AG and PG methods. Methods: A total of 31 patients (11 males, 20 females; average age: 11.6±70.1 yrs) with 44 lung lesions, diagnosed as lung adenocarcinoma between April 2012 and March 2013, were investigated. Whole-body FDG-PET/CT scan was performed with both PG and AG methods in all patients. The maximum standardized uptake value (SUV max) of ...

$Research paper thumbnail of Association between Refractoriness to 131I Therapy for Differentiated Thyroid Carcinoma and 18F-FDG Accumulation in Lung Metastasis$

Archives in Cancer Research, 2017

Annals of Nuclear Medicine, 2021

Objective 123 I metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for the diagnosis of... more Objective 123 I metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for the diagnosis of pheochromocytomas (PHEOs), but some PHEOs are difficult to differentiate from cortical adenoma (CA) or normal adrenal uptake by visual evaluation alone. A new semi-quantitative analysis using 123 I MIBG SPECT/CT is thus expected. Herein, we introduce the tumor-to-liver count ratio (T/L) and the tumor-to-muscle count ratio ( T / M ). Methods We examined the cases of 21 patients with PHEOs (10 males, 11 females; age 24–80, median 61 years) and 23 patients with CA (15 males and 8 females, age 30–78, median 58 years). The visual scoring based on 123 I MIBG planar images (planar score) and SPECT images (SPECT score) was used as the conventional evaluation. Using 123 I MIBG SPECT/CT findings, we calculated the semi-quantitative values of the count ratio using the maximum or mean count of the tumor and the liver or muscle as the reference organ ( T / L max , T / L mean , T / M max and T / M mean ). Each evaluation of the PHEOs and CAs was compared, and the diagnosing performance was evaluated based on an ROC analysis. Results The area under curve (AUC) values were as follows: the planar score, 0.833; SPECT score, 0.813; T / L max , 0.986; T / L mean , 0.975; T / M max , 0.955; and T / M mean , 0.933. The AUC for T / M max was significantly higher than those of the planar score, and SPECT score by ROC analysis ( p < 0.01 each). Conclusion The semi-quantitative value of 123 I MIBG SPECT/CT is more useful than the conventional visual evaluation for differentiating PHEOs from CAs.

Objectives Ra-223 is a promising radionuclide for the treatment of skeletal metastases in castrat... more Objectives Ra-223 is a promising radionuclide for the treatment of skeletal metastases in castration-resistant prostate cancer patients. This study aims to estimate the lower limits for feasible Ra-223 single-photon emission computerized tomography (SPECT) imaging using a Monte Carlo simulation study. Methods The SPECT images were produced on a homemade code: the Monte Carlo simulation of electrons and photons for SPECT (MCEP-SPECT). The National Electrical Manufacturers Association (NEMA) phantom with six hot spheres of diameters of 37, 28, 22, 17, 13, and 10 mm installed inside, was used. The background activity concentration was 0.6 kBq/mL, and the ratios of hot concentrations to the background (R HB) were 25, 20, 15, 10, and 5. When R HB was 15, the background concentrations of 1.5, 0.9, 0.3, and 0.15 kBq/mL were also tested. The energy window was 84 keV±10%. The number of projections was 60/360°, and the acquisition time was 60 s per projection. Two kinds of collimators: middle...

Annals of Nuclear Medicine, 2020

Objective The aim of this study was to evaluate the image quality and the quantification accuracy... more Objective The aim of this study was to evaluate the image quality and the quantification accuracy of Biograph Vision PET/CT scanner as a SiPM-PET in comparison to the conventional PMT-PET, Biograph mCT PET/CT scanner. Methods This study consisted of a phantom study and a retrospective clinical analysis where patients underwent 18 F-FDG PET/CT in both PET systems. The body phantom of the NEMA IEC with 10–37 mm diameter spheres were filled with an 18 F-FDG solution. The root mean square error (RMSE) of SUV, the detectability of 10-mm sphere, NEC phantom , the background variability ( N 10mm ) and the contrast-noise-ratio ( Q H,10 mm / N 10mm ) were calculated based on the phantom analysis. We also examined the quality of the acquired clinical images using the NEC patient , NEC density , SNR liver , SUV liver and SUV lesion . Results In the phantom study on Vision scanner, RMSE was relatively lower when the iteration number was 2, 3 or 4. To satisfy a visual score of 1.5 and the reference range of Q H,10 mm / N 10mm , a 60-s or longer acquisition was required. Our clinical findings show that NEC patient averaged 17.4 ± 1.72 Mcounts/m in mCT and 29.1 ± 2.83 Mcounts/m in Vision. Furthermore, NEC density averaged 0.29 ± 0.05 kcounts/cm 3 in mCT and 0.53 ± 0.09 kcounts/cm 3 in Vision, respectively, whereas SNR liver averaged 14.6 ± 3.77% in mCT and 21.3 ± 1.69% in Vision ( P = 0.0156), respectively. Finally, SUV liver averaged 2.82 ± 0.28 and 2.55 ± 0.30, SUV lesion ranged 1.6–17.6 and 1.9–22.9 in mCT and Vision, respectively. Conclusion SiPM-PET/CT provides superior image quality and quantification accuracy compared to PMT-PET/CT.

International Cancer Conference Journal, 2017

A 67-year-old man with metastatic prostate cancer presented with progression to castration-resist... more A 67-year-old man with metastatic prostate cancer presented with progression to castration-resistant prostate cancer. After sequential therapies with flutamide, estramustine phosphate, docetaxel, enzalutamide, and cabazitaxel for castration-resistant prostate cancer, radium-223 was initiated and continued up to 4 cycles. However, concurrently with radiological and clinical progressions, pancytopenia was observed due to bone-marrow carcinomatosis by prostatic adenocarcinoma. This case suggested that radium-223 should be employed at appropriated timing before appearances of extraosseous and bone-marrow lesions in addition to visceral metastasis.

Nuclear Medicine Communications, 2019

Objective Edge artifacts have been reported on in relation to 18 F-PET using point spread functio... more Objective Edge artifacts have been reported on in relation to 18 F-PET using point spread function correction algorithms. The positron range of 68 Ga is longer than 18 F, and this difference is thought to result in different edge artifacts. The purpose of this study is to clarify the difference in edge artifacts in PET images using point spread function correction in 68 Ga-and 18 F-PET. Methods We used a National Electrical Manufacturers Association International Electrotechnical Commission body phantom. The phantom was filled severally with 68 Ga and 18 F solution. The PET data were obtained over a 90 minutes period using a True Point Biograph 16 scanner. The images were then reconstructed with the ordered subset expectation maximization with point spread function correction. The phantom image analyses were performed by a visual assessment of the PET images and profiles, and an absolute recovery coefficient, which was the ratio of the maximum radioactivity of any given hot sphere to its true radioactivity. Results The ring-like edge artifacts of 68 Ga-PET were less prominent than those in 18 F-PET. The relative radioactivity profiles of 68 Ga-PET showed low overshoots of the maximum radioactivity although high overshoots did appear in 18 F-PET. The absolute recovery coefficients of 68 Ga-PET were smaller than those of 18 F-PET. Conclusion The edge artifacts of 68 Ga-PET were less prominent than those of 18 F-PET, and their overshoots were smaller. The difference in the positron range between 68 Ga and 18 F may possibly result in the difference in edge artifacts of images reconstructed using the point spread function correction algorithm. Nucl Med Commun

International Journal of Clinical Oncology, 2018

Background To evaluate the prognostic outcome and surgical complications in patients with early-s... more Background To evaluate the prognostic outcome and surgical complications in patients with early-stage cervical cancer who underwent sentinel node navigation surgery (SNNS) for hysterectomy or trachelectomy. Methods A total of 139 patients who underwent SNNS using 99m Tc phytate between 2009 and 2015 were evaluated. No further lymph node dissection was performed when intraoperative analysis of the sentinel lymph nodes (SLNs) was negative for metastasis. We compared the surgical complications between the SNNS group and 67 matched patients who underwent pelvic lymph node dissection (PLND) after SLN mapping between 2003 and 2008. We also examined the clinical outcomes in the SNNS group. Results The mean number of detected SLNs was 2.5 per patient. Fourteen of the 139 patients in the SNNS group underwent PLND based on the intraoperative SLN results. The amount of blood loss, the operative time, and the number of perioperative complications were significantly less in the SNNS group than in the matched PLND group. There was no recurrence during a follow-up period ranging from 2 to 88 months (median 40 months) in the SNNS group. Conclusions Using SNNS for early-stage cervical cancer is safe and effective and does not increase the recurrence rate. A future multicenter trial is warranted.

Nihon Hoshasen Gijutsu Gakkai zasshi, 2016

The non-self-shield compact medical cyclotron and the cyclotron vault room were in operation for ... more The non-self-shield compact medical cyclotron and the cyclotron vault room were in operation for 27 years. They have now been decommissioned. We efficiently implemented a technique to identify an activation product in the cyclotron vault room. Firstly, the distribution of radioactive concentrations in the concrete of the cyclotron vault room was estimated by calculation from the record of the cyclotron operation. Secondly, the comparison of calculated results with an actual measurement was performed using a NaI scintillation survey meter and a high-purity germanium detector. The calculated values were overestimated as compared to the values measured using the NaI scintillation survey meter and the high-purity germanium detector. However, it could limit the decontamination area. By simulating the activation range, we were able to minimize the concrete core sampling. Finally, the appropriate range of radioactivated area in the cyclotron vault room was decontaminated based on the resul...

Japanese journal of radiology, 2013

To investigate myocardial viability in chronic ischemic heart disease by myocardial perfusion and... more To investigate myocardial viability in chronic ischemic heart disease by myocardial perfusion and regional contraction analysis using 256-slice MSCT coronary angiography (CCTA). In 30 patients with prior myocardial infarction (MI), CCTA with retrospective ECG-gating and stress-redistribution thallium-201 SPECT were performed. Using the same raw data as used for CCTA, myocardial perfusion imaging (CT-MPI) was reconstructed at four phases during the cardiac cycle. Mean myocardial attenuation and wall thickness at end-systole and end-diastole were measured in the MI areas depicted by SPECT, and they were compared between viable and non-viable segments categorized by SPECT. End-systolic thickness was significantly greater for viable than for non-viable segments (12.0 ± 3.2 vs. 9.6 ± 3.5 mm, p = 0.0017). There was no difference in end-diastolic thickness. Myocardial attenuation was significantly higher for viable than for non-viable segments in the subendocardium (62 ± 13 vs. 70 ± 11 HU,...

The Journal of Physical Chemistry B, 2009

The aggregation behavior of the zinc porphyrin-CD conjugate in a water/ethanol binary mixed solut... more The aggregation behavior of the zinc porphyrin-CD conjugate in a water/ethanol binary mixed solution was investigated. The spectroscopic data and the atomic force microscopy (AFM) image strongly suggest that a part of a Zn porphyrin is included in the-CD nanocavity of another ZnP-CD conjugate at certain concentrations, leading to the formation of Zn porphyrin J-aggregates.

Molecular Crystals and Liquid Crystals, 2009

It is well known that a thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) becomes turbid abo... more It is well known that a thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) becomes turbid above a cloud point (CP) temperature. In this study, the phase transition changes of PNIPAM end-functionalized with pyrenyl group (Py-PNIPAM) were investigated in dilute aqueous solutions. Two types of Py-PNIPAMs were prepared; one is an ester-linkage type (Py-OCO-PNIPAM), and the other an amide-linkage type (Py-NHCO-PNIPAM). From temperature dependence of

Journal of the European Academy of Dermatology and Venereology, 2003

Table 1 Comparison of the recovery periods from aphthae, and the adhesion and phagocytosis rates ... more Table 1 Comparison of the recovery periods from aphthae, and the adhesion and phagocytosis rates of patients in group I and group II before and after treatment Group 1 n = 26 Group 2 n = 22

Clinical Nuclear Medicine, 2009

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare clinical entity where tumor cell embo... more Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare clinical entity where tumor cell embolisms in pulmonary circulation induce thrombotic microangiopathy (TMA), respiratory failure, and subacute cor pulmonale. We describe 3 cases of PTTM that presented as the initial manifestation of metastatic gastric adenocarcinoma with TMA and pulmonary infiltrates. All 3 cases had similar clinical and laboratory features, which included moderate thrombocytopenia without renal failure, hemolysis with extremely high serum lactate dehydrogenase levels, leukoerythroblastosis in peripheral blood smear, altered coagulation tests, lymphadenopathies, and interstitial pulmonary infiltrates. All patients died within 2 weeks of diagnosis. Two cases were initially misdiagnosed as idiopathic thrombotic thrombocytopenic purpura and treated with plasma exchange with no response. One patient had bone marrow infiltration by malignant cells. Autopsies revealed PTTM associated with gastric disseminated adenocarcinoma (signet-ring cell type in 2 patients and poorly differentiated type in 1). PTTM should be considered in the differential diagnosis of patients with fulminant microangiopathic hemolytic anemia, such as atypical thrombotic thrombocytopenic purpura, mainly those with pulmonary infiltrates, disseminated intravascular coagulation, or Trousseau syndrome.

Clinical Nuclear Medicine, 2013

The purpose of this study was to propose a new index that quantifies the heterogeneity of myocard... more The purpose of this study was to propose a new index that quantifies the heterogeneity of myocardial uptake on gated myocardial perfusion SPECT (GMPS) with ²⁰¹Tl and investigate its utility in diagnosing multivessel coronary artery disease (CAD). In 51 patients with CAD, adenosine-stress ²⁰¹Tl GMPS and coronary angiography (CAG) were performed. On the basis of the American Heart Association&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s 17-segment model, segmental percentage uptake on stress, and redistribution images of GMPS were measured at end-systole and end-diastole. The coefficient of variance (CV) of 17 segmental percentage uptake for each patient was used as an estimate of the heterogeneity of myocardial uptake. According to the results of CAG, patients were divided into insignificant coronary artery stenosis (insignificant-CAD), single-vessel CAD, and multivessel CAD groups. The differences in CV among the 3 groups were analyzed by 1-way analysis of variance and Tukey-Kramer test. The diagnostic capability for multivessel CAD was analyzed using the receiver operating characteristics (ROC) curve analysis. Stress end-diastolic CV for patients with multivessel CAD [mean (SD), 18.1% (3.5%)] was significantly greater than that for single-vessel CAD [12.8% (2.9%), P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001] and insignificant-CAD [10.1% (0.9%), P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001]. Stress end-systolic CV for patients with multivessel CAD [23.4% (5.2%)] was significantly greater than that for insignificant-CAD [16.5% (4.1%), P=0.002], whereas there was no difference between single-vessel [20.9% (6.1%)] and multivessel CAD. Using an optimal cutoff of stress end-diastolic CV diagnosed multivessel CAD with a sensitivity of 84%, a specificity of 92%, an accuracy of 88%, and an area under the curve of 0.89. The heterogeneity of myocardial percentage uptake on ²⁰¹Tl GMPS was correlated with the severity of CAD. Stress end-diastolic CV value is a candidate index for differentiating patients with multivessel CAD from single-vessel CAD and insignificant-CAD.

British Journal of Dermatology, 2006

Annals of Nuclear Medicine, 2012

A 26-year-old female who had had a hydatidiform mole at 20 years of age showed high levels of ser... more A 26-year-old female who had had a hydatidiform mole at 20 years of age showed high levels of serum human chorionic gonadotropin. Because pelvic ultrasound did not show any gestational sac in her uterus, she was suspected to have had an extrauterine pregnancy and a spontaneous abortion. About 6 months later, a pulmonary nodule in the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s right upper lung field was found on a routine chest X-ray film. Contrast- enhanced CT scans revealed a solitary lobulated nodule 2.0 × 1.3 × 3.0 cm in diameter in the S2 segment of the right lung. CT suggested a vessel malformation. Positron emission tomography using 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG-PET) was performed and showed weak FDG accumulation (SUVmax = 2.0) in the nodule, which did not positively indicate malignancy. Because a follow-up CT showed a rapid increase in the size of the nodule, partial resection of S2 segment in the right upper lobe was performed. The histopathological diagnosis was a metastasis from choriocarcinoma. The tumor consisted largely of necrosis and hemorrhage, and it was considered to be a major cause of the unusual FDG-PET and CT findings.

Radiology and Medical Diagnostic Imaging

Aim: The purpose of this study was to assess the impact of the collimator in viewing the dopamine... more Aim: The purpose of this study was to assess the impact of the collimator in viewing the dopamine transporter, using 123I ioflupane single-photon emission computed tomography (DaT-SPECT) images utilizing a Monte Carlo simulation. Methods: For the purpose of this study, the Monte Carlo simulation of electrons and photons (MCEP)- SPECT was used. A numerical phantom was created from a real basal ganglia phantom and installed within the code. The specific binding ratios (SBRs) were 5.03 and 2.01 for the background concentration of 7.44 kBq/mL or 7.04 and 3.03 for a background concentration of 5.56 kBq/mL. The simulated images were evaluated using a recovery coefficient (RC). Initially, we simulated the performance of 14 collimators without resolution correction to investigate the impact of the collimator dimension. The effects of two resolution correction methods (collimator broad correction (CBC) and three-dimensional frequency– distance relationship (3D-FDR)) on two reconstruction met...

European Radiology

Objectives To examine the utility of FDG-PET/MRI in patients with epilepsy by comparing the diagn... more Objectives To examine the utility of FDG-PET/MRI in patients with epilepsy by comparing the diagnostic accuracy of PET/MRI and PET/CT in epileptogenic zone (EZ) detection. Methods This prospective study included 31 patients (17 males, 14 females) who underwent surgical resection for EZ. All patients were first scanned using FDG-PET/CT followed immediately with FDG-PET/MRI. Two series of PET plus standalone MR images were interpreted independently by five board-certified radiologists. A 4-point visual score was used to assess image quality. Sensitivities and visual scores from both PETs and standalone MRI were compared using the McNemar test with Bonferroni correction and Dunn’s multiple comparisons test. Results The EZs were confirmed histopathologically via resection as hippocampal sclerosis (n = 11, 35.5%), gliosis (n = 8, 25.8%), focal cortical dysplasia (n = 6, 19.4%), and brain tumours (n = 6, 19.4%) including cavernous haemangioma (n = 3), dysembryoplastic neuroepithelial tumo...