Nihon Hoshasen Gijutsu Gakkai zasshi最新文献

Purpose: In DRLs 2020, in addition to the fluoroscopic dose rate, air kerma at the patient entrance reference point (K_a,r) and air kerma-area product (P_KA) by types of medical treatment and diseases were set as DRL quantity. We surveyed the current equipment setting dose at each facility and the exposure dose in clinical practice. We considered the optimal DRL classification of K_a,r and P_KA for the next DRLs update.

Methods: We conducted a questionnaire survey of 428 facilities in Japan with angiography devices and analyzed the obtained angiography dose data.

Results: Fluoroscopic dose rate, K_a,r, and P_KA were lower values compared to past studies and DRLs 2020 data, and significant differences were observed in K_a,r and P_KA by procedure.

Conclusion: Equipment setting doses have been optimized at each facility, and it is expected that radiological protection will be optimized by setting DRL values that reflect the current situation.

Purpose: This study aimed to evaluate whether low-dose CT imaging using an Sn filter can provide image quality sufficient for the differential diagnosis of cranial deformities in infants while maintaining an effective dose comparable to that of conventional radiography.

Methods: We calculated the effective dose for both head X-ray imaging and low-dose CT with an Sn filter. Phantom images acquired using a CT scanner equipped with an Sn filter were evaluated for bone suture visibility at various conditions (from 10 mAs to 50 mAs, every 10 mAs) using a 4-point visual grading scale. In addition, a visual assessment of low-dose CT versus standard-dose CT was performed for infants with cranial deformities.

Results: The effective dose for 2-directional X-ray imaging was 0.011 mSv. At 50 mAs, the effective dose for low-dose CT was 0.008 mSv, with good visibility of the bone sutures, showing nearly equivalent effective doses. The visual assessment results did not differ significantly between low-dose CT and normal-dose CT for infants with cranial deformities (P>0.05).

Conclusion: Low-dose CT using an Sn filter can visualize the infant skull at an effective dose equivalent to conventional X-ray imaging, and the image quality was found to be sufficient for the differential diagnosis of cranial deformities.

Purpose: To investigate the accuracy of proton density fat fraction (PDFF) measurement using chemical shift-encoded MRI (CSE-MRI) with fast imaging techniques in a phantom.

Methods: A 1.5T imaging system (Prodiva; Philips Healthcare) and PDFF phantom (Fat Fraction Phantom Model 300; Calimetrix) were used in this study. The acquisitions without fast imaging techniques (conventional acquisition), with parallel imaging in phase-encode direction (SENSE acquisition), with compressed sensing (CS-SENSE acquisition), and with parallel imaging in both phase-encode and slice-encode direction (Dual-SENSE acquisition) were performed. The following acceleration factors in SENSE and CS-SENSE acquisition were used: 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, and 8.0. For Dual-SENSE acquisition, the same acceleration factors (1.5, 2.0, 3.0, 4.0, 5.0) were set in each of the two directions. The relationships between reference PDFF values and PDFF measurements obtained using each acquisition were assessed using linear regression analysis and Bland-Altman analysis.

Results: According to the linear regression analysis, the slopes and intercepts of regression lines were from 0.87 to 1.02 and from 0.06% to 3.55%, respectively. According to Bland-Altman analysis, there were fixed bias between reference PDFF values and PDFF measurements obtained using SENSE acquisition with reduction factor 8.0 and Dual-SENSE acquisition with reduction factor 5.0. For CS-SENSE acquisition with reduction factor from 7.0 to 8.0, SENSE acquisition with reduction factor from 3.0 to 8.0, and Dual-SENSE acquisition with reduction factor from 2.0 to 5.0, some vials had ±1.5% or more errors between the reference PDFF values and PDFF measurements in the range of 0% to 50% PDFF.

Conclusion: In CS-SENSE acquisition, the accuracy of PDFF measurement was maintained within 1.5% up to a reduction factor 6.0. The accuracy of PDFF measurement was maintained within 1.5% up to a reduction factor 2.0 in SENSE acquisition and a reduction factor 1.5 in Dual-SENSE acquisition.

Purpose: The purpose of this study was to evaluate the accuracy of dose information obtained from the digital imaging and communications in medicine (DICOM) using the study description for dose management in nuclear medicine (nuclear medicine SD), and to investigate the feasibility of nuclear medicine SD.

Methods: Single-photon emission nuclear medicine examinations and radionuclide therapy from June 1 to June 30 in 2021 (our hospital master period) and 2023 (nuclear medicine SD period) were included. The dose information in the radioisotope administration record was taken as the true value, and the agreement rate of the examination type, radiopharmaceutical, and dose in the dose management system and the error rate of the dose in the nuclear medicine SD period were calculated.

Results: The agreement rate of examination type and radiopharmaceutical was improved from 37.5% to 97.0% by using nuclear medicine SD, and the agreement rate of dose was 54.0%.

Conclusion: The use of nuclear medicine SD has remarkably improved the integrity of dose information. Dose consistency can be improved by unifying the checking system and the input method of dose information. The feasibility of nuclear medicine SD seems to be high in many facilities, and it may contribute to information collaboration among multi-center facilities and enable centralization of dose management systems.