[Questionnaire Survey of Radiation Protection Education in Hospitals].

PURPOSE: The present study aimed to investigate the current situation of radiation protection education for designated radiation workers in hospitals. METHODS: A web-based questionnaire survey was conducted at 1,883 hospitals nationwide with 200 or more beds. RESULTS: Responses from 186 hospitals were included in the analysis. Seven hospitals (6.7%) regulated by the Act on the Regulation of Radioisotopes and six hospitals (7.4%) regulated by only the Ordinance on Prevention of Ionizing Radiation Hazards did not implement radiation protection education. In approximately 6% of the hospitals, designated radiation workers-including physicians, nurses, and radiological technologist-did not attend the education program. The education program attendance rate of physicians was lower than that of nurses. In more than 90% of the hospitals, the frequency of the periodical education program was once every year and lecture time spanned one or less than one hour. The topics of lecture in more than 90% of the hospitals were health effects of radiation and methods of radiation protection for occupational exposure. The radiological technologist was the instructor of the education program in approximately 70% of the hospitals. CONCLUSION: The implementation of radiation protection for designated radiation workers varied from hospital to hospital, and some hospitals did not comply with laws and regulations. Effective and efficient radiation protection education models should be implemented in hospitals.

CRISPR/Cas9 genome editing for comparative genetic analysis related to soy sauce brewing in Aspergillus sojae industrial strains.

Aspergillus sojae has traditionally been used in soy sauce brewing. Genetic modification techniques have been established in A. sojae, but it is difficult to apply them to various industrial strains. Although we have previously developed a CRISPR/Cpf1 system for genetic modification of A. sojae, another genome editing system was required for versatile modification. In addition, repetitive genetic modification using the CRISPR system has not been established in A. sojae. In this study, we demonstrated mutagenesis, gene deletion/integration, and large deletion of a chromosomal region in A. sojae using the CRISPR/Cas9 system. We also successfully performed repetitive genetic modification using a method that involved forced recycling of genome-editing plasmids. Moreover, we demonstrated that the effects of genetic modification related to soy sauce brewing differed among A. sojae industrial strains. These results showed that our technique of using the CRISPR/Cas9 system is a powerful tool for genetic modification in A. sojae.

[Recent Trends in Medical Radiation Protection].

In recent years, the field of medical radiation protection has entered an era of drastic changes. In addition to international trends, it may also be related to the increased awareness of radiation and radiation effects among the Japanese people due to the Fukushima nuclear accident in March 2011. As a result, with the revision of laws and regulations, strict control is required for medical radiation safety management and management of radiation workers. As a recent movement on radiation protection, this article reviews the changes in the threshold dose and dose limit of the lens of the eye, medical radiation safety management due to revision of medical law enforcement regulations, diagnostic reference levels, domestic and international trends regarding gonad shielding during radiography, trends toward new ICRP recommendation, and risk communication from recent trends in medical radiation protection.

[Consideration of Lens of the Eye Protection during Mammography with the Eyelid and the Face Guard].

PURPOSE: In 2011, the International Commissionon Radiological Protection (ICRP) recommended reducing the threshold dose for the lens. Therefore, it is important to reduce the lens exposure dose in medical exposures. In a cranio-caudal (CC) view of mammography, the patient' s lens receives scattered radiation. In this study, we investigated scatter dose around the lens during mammography and reviewed the simple and easy protection methods of the lens. METHODS: Optically stimulated luminescence (OSL) dosimeters were placed in front of the device to obtain scattered radiation intensity distribution. The human phantom was placed in the same way as the CC positioning, and BR-12 phantoms with a thickness of 40 mm was placed on the FPD. Then, the scatter dose around the lens was measured using an OSL dosimeter. In order to confirm the change in the scatter radiation dose by the face guard (FG) and eyelid, we measured and compared under the same conditions the presence of FG and adipose tissue about 1 mm thick assuming the eyelid. RESULTS: Scatter radiation intensity decreased around the FG. When the FG was installed, the scatter dose was reduced about 33%, and when the adipose tissue was pasted on the OSL dosimeter, the scatter dose was reduced about 29%. CONCLUSION: This study suggested that eye closure during mammography was effective in reducing lens exposure. In the future, we would like to expect further protective effects by increasing the thickness of FG and reviewing the materials.

[Proposal for Reduction Measures of Eye Lens Exposure Based on Actual Exposure Management in Radiation-exposed Medical Staff].

PURPOSE: To investigate the actual condition of the crystalline lens equivalent dose and effective dose according to the type of job and the type of duties in a medical institution. We also sought to clarify effective exposure reduction strategies. METHODS: Equivalent crystalline lens doses, effective doses, job type, and duties for 8656 persons · year were obtained from 17 medical facilities. We analyzed the relationship between the effective dose and the crystalline lens equivalent dose in uniform exposure control and non-uniform exposure control conditions. Exposure data were obtained for 13 unique job types and duties. RESULTS: The ratio of the lens equivalent dose to the effective dose of non-uniform exposure managers was 2 to 6 times and varied depending on the occupation. The percentage of persons whose annual lens equivalent dose exceeded 20 mSv was 4.75% for medical doctors, 1.17% for nurses, and 0.24% for radiological technologists. Highly exposed tasks included doctors in cardiology and gastroenterology performing angiography and endoscopy, nurses in endoscopy, and radiological technologists in radiography and CT examinations. CONCLUSION: Thorough unequal exposure control for operations with high crystalline lens exposure, radiation protection education, and effective use of proper personal protective equipment such as the use of radiation protection glasses may reduce lens exposure levels.

The 2020 national diagnostic reference levels for nuclear medicine in Japan.

The diagnostic reference levels (DRLs) are one of several effective tools for optimizing nuclear medicine examinations and reducing patient exposure. With the advances in imaging technology and alterations of examination protocols, the DRLs must be reviewed periodically. The first DRLs in Japan were established in 2015, and since 5 years have passed, it is time to review and revise the DRLs. We conducted a survey to investigate the administered activities of radiopharmaceuticals and the radiation doses of computed tomography (CT) in hybrid CT accompanied by single photon emission computed tomography (SPECT)/CT and positron emission tomography (PET)/CT. We distributed a Web-based survey to 915 nuclear medicine facilities throughout Japan and survey responses were provided by 256 nuclear medicine facilities (response rate 28%). We asked for the facility's median actual administered activity and median radiation dose of hybrid CT when SPECT/CT or PET/CT was performed for patients with standard habitus in the standard protocol of the facility for each nuclear medicine examination. We determined the new DRLs based on the 75th percentile referring to the 2015 DRLs, drug package inserts, and updated guidelines. The 2020 DRLs are almost the same as the 2015 DRLs, but for the relatively long-lived radionuclides, the DRLs are set low due to the changes in the Japanese delivery system. There are no items set higher than the previous values. Although the DRLs determined this time are roughly equivalent to the DRLs used in the US, overall they tend to be higher than the European DRLs. The DRLs of the radiation dose of CT in hybrid CT vary widely depending on each imaging site and the purpose of the examination.

A multicenter study of radiation doses to the eye lenses of medical staff performing non-vascular imaging and interventional radiology procedures in Japan.

PURPOSE: This study aimed to measure the eye lens doses received by physicians and other medical staff participating in non-vascular imaging and interventional radiology procedures in Japan. MATERIAL AND METHODS: From October 2014 to March 2017, 34 physicians and 29 other medical staff engaged in non-vascular imaging and interventional radiology procedures at 18 Japanese medical facilities. These professionals wore radioprotective lead glasses equipped with small, optically stimulated luminescence dosimeters and additional personal dosimeters at the neck during a 1-month monitoring period. The Hp(3) and the Hp(10) and Hp(0.07) were obtained from these devices, respectively. The monthly Hp(3), Hp(10), and Hp(0.07) for each physician and other medical staff member were then rescaled to a 12-month period to enable comparisons with the revised occupational equivalent dose limit for the eye lens. RESULTS: Among physicians, the average annual Hp(3) values measured by the small luminescence dosimeters on radioprotective glasses were 25.5 ± 38.3 mSv/y (range: 0.4-166.8 mSv/y) and 9.3 ± 16.6 mSv/y (range: 0.3-82.4 mSv/y) on the left and right sides, respectively. The corresponding values for other medical staff were 3.7 ± 3.1 mSv/y (range: 0.4-10.4 mSv/y) and 3.2 ± 2.7 mSv/y (range: 0.5-11.5 mSv/y), respectively. CONCLUSIONS: The eye lens doses incurred by physicians and other medical staff who engaged in non-vascular imaging and interventional radiology procedures in Japan were provided. Physicians should wear radioprotective glasses and use additional radioprotective devices to reduce the amount of eye lens doses they receive.

[Examination of Effectiveness Verification and Additional Items in Angiography and IVR of DRLs 2015].

Japanese Diagnostic Reference Levels (DRLs) were released as "Japan DRLs 2015" from Japan Network for Research and Information on Medical Exposure (J-RIME) in June 2015. In "Japan DRLs 2015", DRLs in angiography and interventional procedures are set at a fluoroscopic dose rate of 20 mGy/min at the interventional reference point using a phantom. In order to achieve optimization with DRLs, then it need to be revised regularly. Therefore, we (research group to examine the effect of Japan DRLs 2015 and the necessity of additional items in angiography and vascular interventions) examined the effects of "Japan DRLs 2015" on angiography and interventional procedures. And we also investigated for DRLs revision in the future. As a result, it turned out that it is important to create DRLs in medical procedures that can be effectively used in clinical settings.

[A Questionnaire Survey on the Levels of Perception and Implementation on Diagnostic Reference Levels in Japan (Japan DRLs 2015)].

In June 2015, Japanese diagnostic reference levels (Japan DRLs 2015) was released by Japan Network for Research and Information on Medical Exposures (J-RIME). After six months the release of Japan DRLs 2015, we have conducted a questionnaire and received 222 responses from hospital staff regarding their perception level, and implementation on Japan DRLs 2015 at their facilities. 131 people (59.0%) were familiar with Japan DRLs 2015, of which 56 people (29.2%) were not currently implementation of them. A total of 66 people (30.1%) understood how to implement Japan DRLs 2015. There were 35 people (18.2%) who heard of diagnostic reference levels (DRLs) for the first time through this survey. Those are the levels of perception and implementation on Japan DRLs 2015 became clear. It is necessary to compare the dose levels used at each facility with Japan DRLs 2015 to optimize patient protection during medical exposure. It is essential to continue to grow the medical community's understanding of DRLs with the expanded perception and implementation of this survey as an opinion poll across Japan.

Angular dependence of shielding effect of radiation protective eyewear for radiation protection of crystalline lens.

Radiation protective (RP) eyewear effectively protects crystalline lenses from radiation exposure. A drawback of RP eyewear is the angular dependence of the shielding effect, which results from the design of the eyewear. In this study, 21 models of RP eyewear with different designs and lead equivalences were assessed. Each piece of RP eyewear was hung on a Styrofoam phantom that imitated the head, and a 0.125-cc ionization chamber dosimeter was placed at the position of the crystalline lens. The differences in angular dependence of the shielding effect were evaluated by changing the irradiation angle, and parameters that improved the angular dependence of the shielding effect-sufficient lead equivalence, large coverage design, and minimum gap between the crystalline lens and the RP eyewear-were identified. Thus, the findings highlight the importance of selecting RP eyewear according to the angular distribution and the nature of radiation exposure in the workplace for radiation workers.

[Investigation of patient exposure doses in diagnostic radiography in 2011 questionnaire].

We report here the results of a dose evaluation based on information obtained in a 2011 questionnaire as compared with an investigation made in 2007. Briefly, in general radiography, the dose used in most examinations in 2011 was lower than in 2007. However, since the entrance surface dose for chest X-rays showed an increase, there is a need to standardize the taking of digital images to be able to decrease the dose. Although computed tomography dose index volume (CTDIvol) in CT examinations was higher than that revealed in the 2007 investigation, there is potential for dose reduction.

[Summary of results of the patient exposures in diagnostic radiography in 2011 questionnaire-focus on radiographic conditions-].

We carried out a questionnaire survey to research on radiographic conditions in 3000 institutes. We discussed on radiographic conditions to estimate patient exposures. The collection rate was 24.7%. Most of the institutes shifted to the use of high-voltage generator, digital devices, and filmless equipment. We did not see a shift in this survey of radiographic conditions compared with the 2007 survey.