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Tamio Aburano

Publications and source records attributed to Tamio Aburano.

At least 19 recordsLinked to original sources
PubMed2006

[Survey and analysis of radiation safety management systems at medical institutions--second report: radiation measurement, calibration of radiation survey meters, and periodic check of installations, equipment, and protection instruments].

We carried out a questionnaire survey to determine the actual situation of radiation safety management measures in all medical institutions in Japan that had nuclear medicine facilities. The questionnaire consisted of questions concerning the evaluation of shielding capacity; radiation measurement; periodic checks of installations, equipment, and protection instruments; and the calibration of radiation survey meters. The analysis was undertaken according to region, type of establishment, and number of beds. The overall response rate was 60 percent. For the evaluation of shielding capacity, the outsourcing rate was 53 percent of the total. For the radiation measurements of "leakage radiation dose and radioactive contamination" and "contamination of radioactive substances in the air," the outsourcing rates were 28 percent and 35 percent of the total, respectively (p<0.001, according to region and establishment). For the periodic check of radiation protection instruments, the implementation rate was 98 percent, and the outsourcing rate was 32 percent for radiation survey meters and 47 percent for lead aprons. The non-implemented rate for calibration of radiation survey meters was 25 percent of the total (p<0.001, according to region and establishment). The outsourcing rate for calibration of radiation survey meters accounted for 87 percent of the total, and of these medical institutions, 72 percent undertook annual calibration. The implementation rate for patient exposure measurement was 20 percent of the total (p<0.001, according to number of beds), and of these medical institutions 46 percent recorded measurement outcome.

Calibration↗
PubMed2006

Cerebral activation during withholding urine with full bladder in healthy men using 99mTc-HMPAO SPECT.

UNLABELLED: The aim of this study was to identify the brain areas that control urinary continence in healthy men by 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) SPECT. METHODS: SPECT scans were performed on 15 right-handed healthy male volunteers, 24-45 y old. Each subject was scanned twice without movement in a supine position, and 444 and 555 MBq 99mTc-HMPAO were separately injected intravenously during the following 2 conditions: resting state with an empty bladder and urine-withholding state with a full bladder. The final image during urine withholding was obtained by subtracting the first scan data from the second scan data. The images were analyzed by statistical image analysis software and displayed on Z-score images at a significance threshold of P < 0.05 with correction for multiple comparisons. RESULTS: In the urine-withholding state, as compared with resting, there was a significant increase in tracer activity in the bilateral inferior frontal gyri and the right superior and the middle temporal gyri. Among the regions, the right inferior frontal gyrus was distinctly prominent. When the threshold value was decreased to P < 0.005 without correction, there was a vast network of cortical and subcortical regions involved during urine withholding. CONCLUSION: Our results suggest that the right inferior frontal gyrus plays an important role in brain control of urinary continence. This study also suggests that brain control of continence can be confirmed by statistical image analysis software using SPECT.

Adult↗
PubMed2005

Three-dimensional magnetic resonance imaging after ultrasonography for assessment of fetal gastroschisis.

A 24-year-old woman (Gravida I, Para I) at estimated 32 weeks of pregnancy was referred to our department for evaluation of a suspected fetal gastroschisis. Ultrasound scan revealed multiple loops of dilated bowel outside the fetal abdomen and absence of membrane surrounding the herniated loops of the intestines. Three-dimensional (3D) magnetic resonance imaging was performed to obtain more information on the bowel both outside and inside the abdomen. Images were constructed with T1-weighted fat-suppressed 3D fast low-angle shot sequences using a maximum intensity projection algorithm. The 3D images made possible the realization of fetal bowel conditions with greater definition and accuracy.

Adult↗
PubMed2005

[Survey and analysis of radiation safety management systems at medical institutions--initial report: radiation protection supervisor, radiation safety organization, and education and training].

In this study, a questionnaire survey was carried out to determine the actual situation of radiation safety management systems in Japanese medical institutions with nuclear medicine facilities. The questionnaire consisted of questions concerning the Radiation Protection Supervisor license, safety management organizations, and problems related to education and training in safety management. Analysis was conducted according to region, type of establishment, and number of beds. The overall response rate was 60%, and no significant difference in response rate was found among regions. Medical institutions that performed nuclear medicine practices without a radiologist participating accounted for 10% of the total. Medical institutions where nurses gave patients intravenous injections of radiopharmaceuticals as part of the nuclear medicine practices accounted for 28% of the total. Of these medical institutions, 59% provided education and training in safety management for nurses. The rate of acquisition of Radiation Protection Supervisor licenses was approximately 70% for radiological technologists and approximately 20% for physicians (regional difference, p=0.02). The rate of medical institutions with safety management organizations was 71% of the total. Among the medical institutions (n=208) without safety management organizations, approximately 56% had 300 beds or fewer. In addition, it became clear that 35% of quasi-public organizations and 44% of private organizations did not provide education and training in safety management (p<0.001, according to establishment).

Education, Nursing↗
PubMed2005

Impaired cardiac sympathetic nerve function in patients with Kawasaki disease: comparison with myocardial perfusion.

Kawasaki disease (KD) is a leading cause of CAD in children. The impairment of cardiac sympathetic nerve function (CSNF) in the adult patients with coronary artery disease (CAD) could often be seen. However, little is known concerning the impairment of CSNF in KD patients. We investigated CSNF and its relationship with myocardial perfusion in KD patients. Eleven children with KD and 4 controls were studied with 123I-metaiodobenzylguanidine (MIBG) and stressed 201Tl single photon emission computed tomography. By the findings on coronary artery angiography (CAG), the patients were divided into 2 groups: A, without stenosis; B, with significant stenosis and/or old myocardial infarction. CSNF was evaluated from the uptake of 123I-MIBG. While myocardial perfusion was evaluated from 201Tl uptake. The numbers of patients in the groups A and B were 7 and 4. Perfusion defect was found in 0, and 2 patients in group A (0%), and B (50%). 123I-MIBG defects were found in 1 and 4 patients in the group A (14%) and B (100%). There were excellent concordances between the finding of 201Tl and 123I-MIBG in group A. While in group B, the coronary territories with 123I-MIBG defects were significantly more than those with perfusion defects (p < 0.05). In KD patients, the impairment of CSNF might be subsequent to coronary artery stenosis and was more severe than the injury of myocardial perfusion.

3-Iodobenzylguanidine↗
PubMed2005

Evaluation of normal fatty replacement of the thymus with chemical-shift MR imaging for identification of the normal thymus.

PURPOSE: To clarify the influences of age and gender on normal fatty replacement of the thymus in childhood, adolescence, and early adulthood using chemical-shift MRI. MATERIALS AND METHODS: A total of 95 normal subjects (52 males and 43 females, mean age = 15.6 years, range = 7-25 years) who underwent chemical-shift MRI of the thymus were assessed prospectively. Signal intensity loss (SIL) of the thymus was determined by dividing the thymus/muscle ratio on the opposed-phase image by that on the in-phase image. We evaluated SIL for its correlation with age and gender, and assessed SIL of the thymus with uncommon morphological features. RESULTS: A significant correlation was found between SIL and age (r = 0.750, P < 0.001). There was no significant difference in SIL between the genders. No significant SIL was identified in any of the subjects aged 10 years or less. However, significant SIL was found in 70.8% of those aged 11-20 years, 100% of those aged 21 years or more, and 46.2% of subjects with uncommon morphological features of the thymus. CONCLUSION: Chemical-shift MRI can depict physiologic fatty infiltration within the normal thymus in subjects over 11 years of age. It is crucial to correlate these normal age-related findings with clinical cases in order to avoid misinterpretation.

Adolescent↗
PubMed2004

Correct localization of epileptogenic focus with I-123 iomazenil cerebral benzodiazepine receptor imaging: a case report of temporal lobe epilepsy with discordant ictal cerebral blood flow SPECT.

A 26-year-old female with intractable epileptic seizures was studied with I-123 iomazenil cerebral benzodiazepine receptor, I-123 IMP inter-ictal and Tc-99m ECD ictal cerebral blood flow SPECT. The ictal cerebral blood flow SPECT indicated the location of the seizures to be in the left temporal lobe, where increased regional cerebral blood flow was noted in marked contrast to the inter-ictal SPECT. Ictal electroencephalograms (EEGs) recorded with scalp and sphenoidal electrodes also suggested the left temporal lobe as the location of the seizures. On I-123 iomazenil SPECT, however, decreased benzodiazepine receptor density was demonstrated in the right temporal lobe. MRI showed mild atrophy and abnormal signal intensity in the right temporal lobe. Ictal EEGs recorded with intracranial electrodes revealed that abnormal electrical activity of the brain always emerged from the right temporal lobe and then propagated to the contralateral side. Based on the findings of intracranial EEGs, partial resection of the right anterior temporal lobe including hippocampus was performed. After the surgery, no seizure occurred. Pathological examination of the surgical specimens revealed hippocampal sclerosis. This case suggested that cerebral benzodiazepine receptor imaging with I-123 iomazenil can be helpful for correct localization of epileptogenic foci.

Adult↗
PubMed2004

Optimization of the uptake method for estimating renal clearance of 99mTc mercaptoacetyltriglycine.

OBJECTIVE: To improve the estimation of 99mTc mercaptoacetyltriglycine clearance in the renal uptake method by optimizing the conditions of renal depth, background, threshold for renal boundary determination, and time interval for integrating renal counts. METHODS: Dynamic renal imaging was performed in 232 patients with dual energy window acquisition (main, 140 +/- 14keV; sub, 122.5 3.5keV). For drawing renal regions of interest (ROIs), cut-off methods with 50% and 70% of the highest renal pixel counts were used. For drawing the backgrounds, circumferential and lateral-inferior quadrant peri-renal ROIs were used. For setting the time interval, periods of 1-2, 1-2.5, 1.5-2.5, 1.5-3 and 2-3 min post-injection were used. For determining renal depth, three methods of a theoretical exponential function using scatter fraction, Tønnesen's formula, and linear combination of scatter fraction and Tønnesen's formula were used. The scatter fraction was calculated using the counts in renal ROIs in the two energy windows. Using every combination of these conditions, renal uptake was calculated. As a reference, one-sample clearance was calculated from a blood sample taken at 30 min post-injection following Bubeck's formula. According to the methods for estimating renal depth, three non-linear regression models were derived to convert renal uptake to clearance. Using one-sample clearance and integrated renal counts as dependent and independent variables, data were fitted to the models to determine the necessary constants. The correlations between the model estimated clearances and one-sample clearance were investigated. RESULTS: One-sample clearance ranged from 11 to 404 ml x min(-1) per 1.73 m2. More than half of the regression using renal depth determined by the scatter fraction alone failed to converge. Among the successfully converged regressions, all model estimated clearances showed significant correlations (P<0.01) with one-sample clearance. The best correlation was observed in the model using renal depth determined by the combination of scatter fraction and Tønnesen's formulas, renal ROIs by 50% cut-off, lateral-inferior background and time interval of 2-3 min (r=0.898, P<0.001). CONCLUSION: The renal uptake method for estimating the clearance of mercaptoacetyltriglycine can be improved by the processing conditions proposed here.

Adolescent↗
PubMed2004

Evaluation of the response of metastatic brain tumors to stereotactic radiosurgery by proton magnetic resonance spectroscopy, 201TlCl single-photon emission computerized tomography, and gadolinium-enhanced magnetic resonance imaging.

OBJECT: The goal of this study was to investigate the usefulness of proton (1H) magnetic resonance (MR) spectroscopy to evaluate the response of metastatic brain tumors to stereotactic radiosurgery (SRS) in comparison with Gd-enhanced MR imaging and single-photon emission computerized tomography with administration of thallium-201 chloride (201TlCl-SPECT). METHODS: Forty patients with a total of 47 metastatic brain tumors were evaluated. The primary lesion was identified in all cases. Stereotactic radiosurgery was effective in 37 lesions. All patients were examined using Gd-enhanced MR imaging before and after SRS. Thalium-201 chloride was administered to 27 patients with 34 tumors and SPECT images were obtained. Proton MR spectroscopy was performed in 36 patients who harbored 43 tumors. On Gd-enhanced MR images, a decrease in the volume of the Gd-enhanced lesion and a change in the enhanced effect in the lesion after treatment were recognized as showing the effectiveness of SRS between 1 and 3 months or more (mean 8.54 +/- 3.58 weeks). In 201TlCl-SPECT studies, the ratio of lesion to normal brain decreased from 2 weeks to 2 months (mean 5.03 +/- 2.77 weeks) after radiosurgery. On 1H-MR spectroscopy images a high choline (Cho) peak and a lipid-dominant (Lip) peak were observed in 25 lesions and a high Cho peak and a lactate-dominant (Lac) peak were observed in 12 lesions before SRS. A decrease in the Cho peak, a disappearance of the Lac peak, and an increase in the Lip peak were observed between 1 week and 1 month (mean 2.76 +/- 1.62 weeks) after treatment. CONCLUSIONS: Based on histopathological findings obtained at autopsy or at surgery, we assume that a high Cho peak may be observed in viable tumor tissue and a Lip peak in areas of necrosis. The results indicate that 1H-MR spectroscopy is potentially a more sensitive tool in evaluating the response to SRS than 201TlCl-SPECT or Gd-enhanced MR imaging and that it can be used earlier for this purpose than those other imaging methods.

Adult↗
PubMed2004

[Survey and analysis of radiation safety education at radiological technology schools].

We carried out a questionnaire survey of all radiological technology schools, to investigate the status of radiation safety education. The questionnaire consisted of questions concerning full-time teachers, measures being taken for the Radiation Protection Supervisor Qualifying Examination, equipment available for radiation safety education, radiation safety education for other departments, curriculum of radiation safety education, and related problems. The returned questionnaires were analyzed according to different groups categorized by form of education and type of establishment. The overall response rate was 55%, and there were statistically significant differences in the response rates among the different forms of education. No statistically significant differences were found in the items relating to full-time teachers, measures for Radiation Protection Supervisor Qualifying Examination, and radiation safety education for other departments, either for the form of education or type of establishment. Queries on the equipment used for radiation safety education revealed a statistically significant difference in unsealed radioisotope institutes among the forms of education. In terms of curriculum, the percentage of radiological technology schools which dealt with neither the shielding calculation method for radiation facilities nor with the control of medical waste was found to be approximately 10%. Other educational problems that were indicated included shortages of full-time teachers and equipment for radiation safety education. In the future, in order to improve radiation safety education at radiological technology schools, we consider it necessary to develop unsealed radioisotope institutes, to appoint more full-time teachers, and to educate students about risk communication.

Data Collection↗
PubMed2004

[Imaging findings of pulmonary vascular disorders in portal hypertension].

PURPOSE: The purpose of this study was to demonstrate and compare the imaging findings of hepatopulmonary syndrome and portopulmonary hypertension. MATERIALS AND METHODS: We retrospectively reviewed the imaging findings of five patients with hepatopulmonary syndrome and four patients with portopulmonary hypertension. We evaluated chest radiographs, chest and abdominal computed tomography (CT) scans, 99mTc-macroaggregated albumin (MAA) lung perfusion scans, and pulmonary angiograms. RESULTS: In patients with hepatopulmonary syndrome, the presence of peripheral pulmonary vascular dilatation was detected by chest radiograph, chest CT scan, and pulmonary angiogram, especially the basilar segment. 99mTc-MAA lung perfusion scan showed extrapulmonary tracer distribution (brain, thyroid, and kidney), which revealed pulmonary R-L shunting. In patients with portopulmonary hypertension, chest radiographs and chest CT scans showed the classic findings of primary pulmonary hypertension. In patients with both disorders, extrahepatic features of portal hypertension including ascites, splenomegaly, and portosystemic collateral vessels were seen on abdominal CT. CONCLUSION: In conclusion, chest radiographs and CT in hepatopulmonary syndrome usually showed peripheral pulmonary vascular dilatation, whereas those in portopulmonary hypertension showed central pulmonary artery dilatation. The extrahepatic features of portal hypertension might be helpful for the diagnosis of both disorders.

Adolescent↗
PubMed2003

Primary clear cell sarcoma (malignant melanoma) in the right radius.

Clear cell sarcoma (malignant melanoma) originating in bone is an extremely rare occurrence, which has been reported twice previously. It is challenging to differentiate this neoplasm from skeletal metastasis of malignant melanoma because it shows no specific imaging, pathological or immunohistochemical features. However, this differentiation is clinically important due to significant differences in patient management. In this article, we present the case of a 55-year-old man with primary clear cell sarcoma arising in the right radius.

Bone Neoplasms↗
PubMed2003

Estimation with Tc-99m tetrofosmin SPECT of salvaged myocardial mass after emergent reperfusion therapy in acute myocardial infarction.

OBJECTIVES: The purpose of this study was to validate a new quantitative index of salvaged myocardial mass calculated from Tc-99m tetrofosmin SPECT for evaluating the therapeutic effect of emergent reperfusion therapy in acute myocardial infarction (AMI). METHODS: Tc-99m tetrofosmin SPECT was performed before and after emergent percutaneous transluminal coronary angioplasty (PTCA) in eight patients with AMI. In the pre-PTCA study, Tc-99m tetrofosmin was injected before emergent PTCA. Two weeks after the PTCA, post-PTCA study was performed. As a quantitative index of salvaged myocardial mass, salvaged myocardial volume (SMV) was defined as the difference of myocardial functional volume between the SPECT studies before and after the PTCA. To investigate the clinical significance of SMV, SMV was compared with the grade of therapeutic efficacy determined visually from pre- and post-PTCA SPECT images and clinical parameters, namely peak creatine phosphokinase level (pCK) and the time from the onset of the AMI to reperfusion (RPT). RESULTS: SMV showed a significant correlation with the visual grade of therapeutic efficacy (r = 0.737, p < 0.037) and a trend toward significant correlation with pCK (r = -0.622, p < 0.1). SMVs in early- and late-reperfusion groups (RPT < or = 6 hr and RPT > 6 hr) were 30.0 +/- 14.0 and -6.2 +/- 25.5 ml, showing a greater mean SMV value in the early-reperfusion group (p < 0.07). CONCLUSION: SMV could be used as a quantitative index of salvaged myocardial mass for evaluating the therapeutic effect of emergent reperfusion therapy.

Aged↗
PubMed2003

Comparison of myocardial fatty acid metabolism with left ventricular function and perfusion in cardiomyopathies: by 123I-BMIPP SPECT and 99mTc-tetrofosmin electrocardiographically gated SPECT.

OBJECTIVE: To investigate myocardial fatty acid metabolism and its relationship with left ventricular (LV) function and perfusion in hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). METHODS: Thirty-nine patients with cardiomyopathies (58 +/- 14 y), comprising 15 DCM and 24 HCM, and 9 age-matched healthy controls were studied with 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and 99mTc-tetrofosmin (TF) electrocardiographically gated SPECT. As parameters of myocardial fatty acid metabolism, the heart-to-mediastinum ratio (H/M) and global washout of BMIPP were calculated from early and delayed planar images, while regional BMIPP uptake and washout were calculated from SPECT. In TF study, the H/M (H/M-TF) and LV ejection fraction (LVEF) were calculated as global parameters of perfusion and function, while regional TF uptake and wall thickening index were calculated as regional parameters of perfusion and function using the Quantitative Gated SPECT software. The differences in the parameters and the correlations between the parameters from the 2 studies were investigated by one-way ANOVA and multiple linear regression analysis. RESULTS: BMIPP uptake was decreased (p < 0.05), and its washout was increased (p < 0.05) in DCM and HCM. In multiple linear regression analysis, global BMIPP parameters showed no significant correlation with LVEF (p > 0.05), but showed a significant correlation with H/M-TF (p < 0.05) in DCM and HCM. According to the partial correlation coefficient, early H/M was the only significant factor (p < 0.05) for predicting H/M-TF in DCM and HCM. Multiple linear regression analysis on regional parameters showed regional BMIPP parameters had no correlation with regional function (p > 0.05) but had a significant correlation with regional perfusion (p < 0.0001) in DCM. In HCM, regional BMIPP parameters showed significant multiple linear correlations with both regional function (p < 0.005) and perfusion (p < 0.0001). According to the partial correlation coefficients, delayed regional BMIPP uptake was the most significant factor for predicting regional function in HCM, while early regional BMIPP uptake was the only or the most significant factor for predicting regional perfusion in DCM and HCM, respectively. CONCLUSION: In DCM, BMIPP uptake and washout could not reflect LV function. In HCM, regional delayed BMIPP uptake might be useful for evaluating regional function. In DCM and HCM, early BMIPP uptake might be largely determined by myocardial perfusion.

Adolescent↗
PubMed2003

Improved accuracy in estimation of left ventricular function parameters from QGS software with Tc-99m tetrofosmin gated-SPECT: a multivariate analysis.

UNLABELLED: The purpose of this study was to verify whether the accuracy of left ventricular parameters related to left ventricular function from gated-SPECT improved or not, using multivariate analysis. METHODS: Ninety-six patients with cardiovascular diseases were studied. Gated-SPECT with the QGS software and left ventriculography (LVG) were performed to obtain left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV). Then, multivariate analyses were performed to determine empirical formulas for predicting these parameters. The calculated values of left ventricular parameters were compared with those obtained directly from the QGS software and LVG. RESULTS: Multivariate analyses were able to improve accuracy in estimation of LVEF, EDV and ESV. Statistically significant improvement was seen in LVEF (from r = 0.6965 to r = 0.8093, p < 0.05). Although not statistically significant, improvements in correlation coefficients were seen in EDV (from r = 0.7199 to r = 0.7595, p = 0.2750) and ESV (from r = 0.5694 to r = 0.5871, p = 0.4281). CONCLUSION: The empirical equations with multivariate analysis improved the accuracy in estimating LVEF from gated-SPECT with the QGS software.

Adolescent↗
PubMed2003

Characterization of the normal and hyperplastic thymus on chemical-shift MR imaging.

OBJECTIVE: We designed our study to prospectively assess a potential role for chemical-shift MR imaging in identifying a thymus that has not been completely replaced by fat tissue. CONCLUSION: The thymic tissue revealed homogeneous decrease in intensity on opposed-phase MR images relative to that seen on in-phase images in 15 healthy volunteers and two patients with hyperplastic thymus. Chemical-shift MR imaging may be useful in identifying normal thymic tissue and the hyperplastic thymus in early adulthood.

Adolescent↗