Masahiro Fukushi

Learn More
We aimed to determine the difference in tumor volume associated with the reconstruction model in positron-emission tomography (PET). To reduce the influence of the reconstruction model, we suggested a method to measure the tumor volume using the relative threshold method with a fixed threshold based on peak standardized uptake value (SUVpeak). The efficacy(More)
The first objective in this study was to identify the errors of incidents and accidents that occurred in general and mobile X-ray examinations. Based on the analysis of results, the second purpose in this study was to propose useful measures to prevent such errors. As much as 553 radiological technologists in the Gunma Prefecture were surveyed on their(More)
OBJECTIVE Improvement in the diagnostic accuracy of lymph node (LN) metastases of colorectal cancer by optimizing the reconstruction parameters was studied, including a phantom study and clinical studies. METHODS In the experimental study, the contrast ratio was evaluated using a standard image quality phantom, changing the iteration number of ordered(More)
In cardiac imaging with 201Tl, the collimator for low energy high resolution is generally used, and also the energy window, which is set on the spectral display of a pulse height analyzer of a scintillation camera, is chosen 70 +/- 12.5 keV. The purpose of this study is to discuss those conditions in 201Tl imaging with the scintillation camera. Two types of(More)
OBJECTIVE We studied the improvement of the detect-ability of lymph node (LN) metastases from colorectal cancer in (18)F-fluorodeoxyglucose positron emission tomography (FDG PET)/computed tomography (CT) by analyzing the acquired counts with a statistical method. METHODS Thirty-nine metastatic LNs from 32 cases with colorectal cancer were included in this(More)
OBJECTIVE Strontium-89 ((89)Sr) chloride has been used to treat metastases in bone. A method to visualize the distribution of (89)Sr chloride with a scintillation camera was developed in 1996. Studies using bremsstrahlung imaging have shown that (89)Sr accumulates in bone and that the bremsstrahlung generated from biological tissue surrounding bone does not(More)
The monitoring of absorbed dose rate in air has been carried out continually at various locations in metropolitan Tokyo after the accident of the Fukushima Daiichi Nuclear Power Plant. While the data obtained before the accident are needed to more accurately assess the effects of radionuclide contamination from the accident, detailed data for metropolitan(More)
The optimal injection dose for imaging of the pelvic region in 3D FDG PET tests was investigated based on the noise-equivalent count (NEC) rate with use of an anthropomorphic pelvis phantom. Count rates obtained from an anthropomorphic pelvis phantom were compared with those of pelvic images of 60 patients. The correlation between single photon count rates(More)
OBJECTIVE This work assessed the usefulness of fully three-dimensional ordered subset expectation maximization (3D-OSEM) algorithm for lymph node (LN) metastases from lung cancer. 3D-OSEM images were evaluated by comparing them with those reconstructed by conventional algorithms, such as conventional OSEM algorithm (2D-OSEM) for 2D acquisition and Fourier(More)
A car-borne survey was made in metropolitan Tokyo, Japan, in December 2014 to estimate external dose. This survey was conducted for all municipalities of Tokyo and the results were compared with measurements done in 2003. The ambient dose rate measured in the whole area of Tokyo in December 2014 was 60 nGy h(-1) (23-142 nGy h(-1)), which was 24% higher than(More)