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.

The International Commission on Radiological Protection recommends adaptation of the diagnostic reference levels as an indicator of optimization of protection, and diagnostic reference levels of 2015 were also published in Japan in 2015 (Japan DRLs 2015). The entrance surface dose (ESD) is evaluated to the published standard subject thickness in Japan DRLs 2015. However, the standard radiographic settings of each facility may not be a radiographic condition of the standard subject thickness of Japan DRLs 2015. We measure and record the thickness of the subject in every examination, and it can solve this problem, but it is difficult to carry out it in the actual clinical scene. In this study, we aimed to estimate the subject thickness by using chest clinical images and to calculate ESD for each radiography. We evaluated and compared with Japan DRLs 2015 using these data. The subject thickness was estimated from 200 cases of digital imaging and communications in medicine (DICOM) image obtained by both the frontal and lateral views of the chest radiography. Also, at the same time, the radiographic settings were acquired from the information of the DICOM tag. The subject thickness was 23.60 cm on the average, and the median of the ESD was 0.104 mGy. Also, the median of the ESD at the standard subject thickness of 20 cm in Japan DRLs 2015 was 0.075 mGy. The ESD can be calculated without measuring the body thickness of the patient of every examination by using the method of this study.

Purpose: To assess the dose reduction of radiologists by using angular beam modulation (ABM) and radiation protection drape during computed tomography (CT) fluoroscopy. Materials and Methods: The phantom was set on the lower that is 15 cm from the isocenter position. We measured the radiation exposure around the phantom with radiophotoluminescence glass dosimeters. The space radiation dose rate was measured with an ionization chamber dosimeter in the CT room. Results: The dose rate of finger radiation exposure was 67% at assumed assist tool position with ABM. And the dose rate of finger radiation exposure with the combination of ABM and radiation protection drape was 33%. The space dose rate of exposure with the combination of ABM and radiation protection drape was 49% at 150 cm. Conclusion: The combination of ABM and radiation protection drape can reduce finger radiation exposure at assumed assist tool position. The space dose rate of the standing position of radiologists can get a clear dose of radiation reduction by the combination of both.

With shortening of the gantry of magnetic resonance imaging (MRI) systems, large field-of-view (FOV) imaging has become difficult because static magnetic field nonuniformity and gradient magnetic field nonlinearity exacerbate geometric distortion of MR images. However, results of earlier studies have demonstrated that view angle tilting (VAT) can reduce severe image distortion attributable to local susceptibility effects of metals. Although VAT is usually applied to local magnetic field nonuniformity, in principle VAT is expected to correct distortion also for peripheral images in large-FOV MRI. Results from this phantom experiment using VAT with large-FOV verified the effectiveness of distortion correction. The experiment using VAT showed reduction of maximum distortion from 23.6 to −1.9 mm. Furthermore, results of a volunteer study confirmed the distortion correction capability of VAT: it reduced distortion and improved visibility of the anatomical structure. In conclusion, experimentally obtained results underscore VAT effectiveness for improving distortion in large-FOV MRI.

The purpose of this study was to evaluate the enhancement profile of 1.0M gadobutrol (high concentration: HC) in comparison to 0.5M gadopentetate dimeglumine and gadoterate meglumine (low concentration: LC) in dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of prostate. In total, 48 patients who were diagnosed with prostate cancer by radiologist were included. Each patient was examined after intravenous injection of 0.1 mmol/kg body weight contrast agent with flow rate of 1.5 (HC) or 3.0 mL/s (LC). Circular regions of interest were placed at prostate cancer (PCa) and normal peripheral zone (normal PZ) in DCE-MRI. The enhancement curves were calculated as a relative enhancement. Statistical analysis was performed by Mann-Whitney U test (p<0.05 were considered significant). As a result, the enhancement at first phase of HC was significantly lower compared with LC in PCa (HC, 0.47; LC, 0.85; p=0.029), and in normal PZ (HC, 0.12; LC, 0.22; p=0.033). The enhancement of HC in PCa was significantly higher compared with LC at late phase. Although not significant, a similar tendency was observed in normal PZ. The present study suggested that the enhancement profile with HC was higher at late phase but the rise of the enhancement curve with HC tended to be delayed.

Purpose: The purpose of the study was to examine the metal artifact-reducing effects of single energy metal artifact reduction (SEMAR) at different rotation time. Methods: Helical and volume scans were employed to photograph a self-made phantom at various rotation time. Metal artifacts were examined using artifact index (AI) values and visual scores. Results: At rotation times of 0.35, 0.4, 0.5, 0.6, 0.75, and 1.0 s/rotation on the helical scans (SEMAR-ON), AI values were 66.6, 64.3, 39.7, 39.7, 40.8, and 15.4, respectively, and visual scores were 3.2, 3.4, 3.0, 3.1, 3.0, and 2.8, respectively. Similar results were obtained on the volume scans. Specifically, the AI values reduced with a decreasing rotation time, although the visual scores did not significantly differ with a rotation time changes. Conclusion: The metal artifact-reducing effects of SEMAR are not altered by the rotation time.

A survey on recognition, utilization, and evaluation for diagnostic reference levels (DRLs) after establishing Japan DRLs 2015 in the field of X-ray computed tomography (CT) was conducted for members of Japanese Society of Radiological Technology using web-based questionnaire system. The survey consisted of provincial branches to which respondents belong, their occupation, years of professional experience, years of experience in X-ray CT section, recognition of DRLs, and utilization and evaluation of DRLs in the field of X-ray CT section. Each survey item had one to eight questions. A total of 369 members completed the questionnaire. Among them, 295 out of 369 (79.9%) members knew that DRLs were released in Japan. After establishing the DRLs, 226 of 330 (68.5%) and 123 of 319 (38.6%) members investigated the doses used for adult and pediatric CT at their facilities, respectively. Although 345 of 369 (93.5%) members answered that DRLs are necessary for the field of X-ray CT, only 142 of 369 (38.5%) members thought that the established DRLs are enough to use in the field of X-ray CT. The survey has clarified the current status of recognition, utilization, and evaluation for DRLs in the field of X-ray CT after establishing the DRLs in Japan.

A 3D printing emerges as a common procedure in clinical radiology practice after installation of a module that converts the digital imaging and communications in medicine (DICOM) dataset into stereolithography (STL) data on medical workstations. However, they did not conventionally provide the appropriate filtering, sculpting, hollowing out, and Boolean (subtraction) operations on STL data. These functions are indispensable to handle the STL data to fabricate the smooth, low-cost, and sophisticated models. Here are some tips for handling the 3D data with three software packages through making a sample lumbar spine model. Because they are all free- and open-source software with the exception of Boolean operations, they could make it easy for anyone to fabricate their 3D model imaged by CT or MRI. We tested the loop subdivision surface algorithms for the smoothing, the sculpting function for removing a sharp prick, and the hollowing function to save the cost. Computer-aided design (CAD) is also used to fabricate the devices in medical research. We designed and developed a cap attached to a glass dosimeter to show the effectiveness of CAD in radiological research. Lastly, we discuss the important matters for 3D printing and examples of the clinical applications.