Purpose: We have been using a paper-based hard copy print (paper print) system of X-ray images, in which digital imaging and communications in medicine (DICOM) data can be directly output on papers from medical imaging systems or from a picture archiving and communication system (PACS) server, and they are utilized as patient referral materials or for preoperative planning. The purpose of this study was to compare the display performance of X-ray images on the printed paper and that on the liquid crystal display (LCD). Methods: We measured contrast response to verify consistency of image appearance on both display systems. The contrast resolution was assessed by a CDRAD phantom. The spatial resolution was assessed by an X-ray test chart. Results: The contrast response of the paper printer was not concordant with the grayscale standard display function (GSDF). The difference between the measured contrast response and the ideal GSDF on the paper was large in the high-density area. The low-contrast resolution on the paper was inferior to that on the LCD. The spatial resolving power on the paper was superior to that on the LCD. Conclusion: The display performance of the paper printer for X-ray images was clarified. X-ray images printed on the paper should be used carefully taking account of their characteristics of display performance.

Purpose: In imaging examinations of patients with hearing impairment, poor image quality due to poor respiratory arrest is a problem directly related to diagnostic imaging. Although there have been studies of non-sound instructions, there have been few quantitative studies using changes in brightness. The purpose of this study was to investigate whether changes in room brightness can be used as a respiratory cessation indicator. Methods: Fourteen patients were imaged using the 2D FIESTA and LAVA-Flex methods on an MRI system under free respiration, voice-guided cessation of respiration (voice instruction), and room brightness change (light/dark instruction), and compared. Results: The positional fluctuation of the top of the liver by the 2D FIESTA method showed a large positional fluctuation under free breathing, while the positional fluctuation was small under voice instruction and light/dark instruction. The images obtained by the LAVA-Flex method was significantly degraded by motion artifacts under free breathing, whereas there were fewer motion artifacts under voice instruction and light/dark instruction, and the two were the same with no significant difference in visual evaluation. Conclusion: The visual cessation of respiration instruction by changing the brightness of the room is as effective as the audible cessation of respiration instruction, suggesting that it can be applied clinically.

Purpose: Respiratory-triggered-diffusion-weighted imaging (R-DWI) of the liver often results in poor image quality under the diaphragmatic dome on the cephalic side of the liver (hepatic dome) secondary to magnetic field inhomogeneity in liver magnetic resonance imaging (MRI). Hence, the usefulness of additional breath-hold-DWI (B-DWI) focusing on the hepatic dome was investigated. Methods: A total of 22 patients (14 men and 8 women; mean age 69.0±11.7 years) who underwent ethoxybenzyl (EOB)-MRI at our hospital between July and August, 2022 using a 3.0 T MRI system were included. One radiologist and three radiology technologists visually assessed the visibility of R-DWI and B-DWI in the hepatic dome on a 4-point scale (1 to 4). Additionally, the apparent diffusion coefficient (ADC) values of the hepatic parenchyma on each DWI were compared. Results: B-DWI improved visibility in the hepatic dome compared to R-DWI (2.67±0.71 vs. 3.25±0.43, p<0.05). No significant difference was found in the ADC values for each DWI. Conclusion: B-DWI has excellent visibility in the hepatic dome and is expected to complement R-DWI. Therefore, B-DWI is very useful as an additional imaging in EOB-MRI.

Purpose: The purpose of this study was to evaluate the residual radioactivity in the syringe and route of administration of a low fluid volume ^99mTc-macro aggregated albumin (MAA) intended for pediatric nuclear medicine examinations. Method: We evaluated the residual characteristics, as the effect of elapsed time from drawing up of radiopharmaceuticals to plastic syringe to administration, and the effect of volume of ^99mTcO₄⁻ solution to be labeled, the effect of rinsed times of plastic syringe, effect of dose of calculated by consensus guidelines for pediatric nuclear medicine and residual location in injection sets with ^99mTc-MAA. Residual radioactivity was measured using planar images obtained by the gamma camera. Results: Residual radioactivity rate of ^99mTc-MAA, ^99mTc-MAG₃, ¹²³I-IMP showed 41.3±1.6%, 14.4±0.6%, 14.6±2.0%, respectively. ^99mTc-MAA clearly showed a higher residual rate. Residual radioactivity rate increased with the extension of the elapsed time, and reached a high value of 41.3% in 30 minutes. Residual radioactivity rate was dependent on the different volume of ^99mTcO₄⁻ to be labeled (4.0 ml and 8.0 ml). Residual radioactivity rate did not change when the number of rinsed was more than one. Residual rate was around 40% at all doses of calculated by consensus guidelines for pediatric nuclear medicine. Conclusion: ^99mTc-MAA showed the highest residual radioactivity rate among radiopharmaceuticals used in pediatric nuclear medicine examinations. The factor that most affected the residual radioactivity rate of ^99mTc-MAA was the elapsed time from draw up to the plastic syringe to administration.

Three-dimensional (3D) images, which are acquired by X-ray computed tomography (CT), are widely used in medical diagnosis and treatment. Recently, advances in image processing functions of 3D image analysis workstations have made it possible to confirm actual procedures, approach lesions from directions that are not visible during surgery, and observe important structures by moving images on the workstation. This is useful in providing a variety of information on the pathology in advance. However, depending on the manipulation of the creator, the 3D images provided can vary greatly in terms of the omission of blood vessels and tumors, the background color, the colors of organs, and the presentation including rotation directions and angles. In this study, we decided to create a manual for 3D image creation using our web hosting service to standardize the 3D images to be provided. In particular, dynamic content using the HyperText Markup Language (HTML) was created and posted to provide a useful support tool for 3D image creation. In addition, the data can be accessed via the Internet within the hospital, making them widely available in clinical and educational settings.

Purpose: The aim of this study was to investigate the leakage radiation dose rate on the surface of an auto infusion device in ¹⁸F-fludeoxyglucose (FDG) positron emission tomography. Method: We preliminary measured the radioactivity of delivery-supplied FDG drugs. Leakage radiation doses on the six (front, rear, right, left, top, and bottom) surface points of the auto infusion device were measured ninety minutes before the assay time using an energy-compensated gamma scintillation survey meter and an ionization chamber-type survey meter. Result: Leakage radiation doses on the front, rear, right, left, and top surfaces were less than 7 µSv/h and satisfied specification of the auto infusion device. However, a leakage dose exceeding 40 µSv/h was detected on the bottom surface.