Eye lens dose in spine surgeons during myelography procedures: a dosimetry study.

To determine the eye lens dose (3 mm dose equivalent [Hp(3)]) received by spine surgeons during myelography and evaluate the effectiveness of radiation-protective glasses and x-ray tube system positioning in reducing radiation exposure. This study included spine surgeons who performed myelography using over- or under-table x-ray tube systems. Hp(3) was measured for each examination using a radio-photoluminescence glass dosimeter (GD-352M) mounted on radiation-protective glass. This study identified significantly high Hp(3) levels, especially in the right eye lens in spinal surgeons. The median Hp(3) values in the right eye were 524 (391-719) and 58 (42-83)µSv/examination for over- and under-table x-ray tube systems, respectively. Further, Hp(3)AK, which was obtained by dividing the cumulative air kerma from Hp(3), was 8.09 (6.69-10.21) and 5.11 (4.06-6.31)µSv mGy-1for the over- and under-table x-ray tube systems, respectively. Implementing radiation-protective glasses resulted in dose reduction rates of 54% (50%-57%) and 54% (51%-60%) for the over- and under-table x-ray tube systems, respectively. The use of radiation protection glasses significantly reduced the radiation dose in the eye lens during myelography, with the most effective measures being the combination of using radiation protection glasses and an under-table x-ray tube system.

Occupational radiation dose on the hand of assisting medical staff in diagnostic CT scans.

Chronic radiation exposure increases the risk of skin damage of medical personnel engaged in radiology. However, hand dose measurements in computed tomography (CT) for diagnostic purposes have not been evaluated. The occupational radiation dose to the hands of CT assistants was herein investigated to evaluate its compliance with the equivalent dose limit for the hand (500 mSv/year). The occupational doses of nine CT assistants were measured in 89 cases (April 2017-May 2018) by installing radio-photoluminescence glass dosemeters (GD-302 M) (70-µm dose-equivalent conversion coefficient = 0.37) on the dorsal aspect of both hands. The occupational dose to the hand was the highest with head holding (right: 1.14 mSv/CT scan, left: 1.07 mSv/CT scan). Considering the results for annual work, even for head holding, the hand dose of the CT-assisting personnel was insignificant. However, CT assistants should be mindful of the possibility of locally higher doses to hands.

DOSE MEASUREMENT PRECISION OF AN RPLD-BASED EYE LENS DOSEMETER APPLICABLE TO THE MEDICAL SECTOR.

We demonstrate a practical calibration method and its applicability for a commercially available radiophotoluminescence dosemeter (RPLD), i.e. the GD-352M (AGC Techno Glass, Shizuoka, Japan) to eye lens dose monitoring, by performing the calibration according to the ISO recommendations. The calibration was then verified through a series of experiments. For verification of the derived calibration factor (1.21 ± 0.04, k = 1) of the RPLD, we performed standard irradiations in the ISO narrow series X-ray reference fields and the simulation measurements in the actual radiation fields in a hospital. The TLD-based commercially available dosemeters, DOSIRIS™ was also put on the ISO cylinder phantom and the RANDO phantom together with the GD-352M in the verification experiments. The personal dose equivalents Hp(3) obtained from the GD-352M and those obtained from the DOSIRIS™ were in good agreement with each other. Our results demonstrate the proper calibration of a commercially available RPLD that is applicable to the additional monitoring of the lens of the eyes for medical staff.

The Effect of Pre-Operative Verbal Confirmation for Interventional Radiology Physicians on Their Use of Personal Dosimeters and Personal Protective Equipment.

Interventional radiology (IR) physicians must be equipped with personal passive dosimeters and personal protective equipment (PPE); however, they are inconsistently used. Therefore, we aimed to explore practical measures to increase PPE usage and ascertain whether these measures could lead to an actual decrease in exposure doses to IR physicians. Dosimeters and PPE were visually inspected. Then, a pre-operative briefing was conducted as a direct intervention, and the use of dosimeters and PPE was verbally confirmed. Finally, the intervention effect was verified by measuring the use rates and individual exposure doses. Because of the intervention, the use rate markedly improved and was almost 100%. However, both the effective dose rate (effective dose/fluoroscopy time) and the lens equivalent dose rate (lens equivalent dose/fluoroscopy time) showed that the intervention led to a statistically significant increase in exposure (effective dose rate: p = 0.033; lens equivalent dose rate: p = 0.003). In conclusion, the proper use of dosimeters and PPE raised the radiation exposure values for IR physicians immediately after the intervention, which was hypothesized to be due to the inclusion of exposure overlooked to date and the changes in the dosimeter management method from a single- to a double-dosimeter approach.

CONTRIBUTION OF ORGAN-BASED TUBE CURRENT MODULATION TO THE REDUCTION OF LENS EXPOSURE DOSE IN HEAD 4D CT IMAGING: A PHANTOM STUDY.

The purpose of this study was to evaluate the effectiveness of organ effect modulation (OEM) in reducing the lens dose in 4D computed tomography (CT) of the head in volume-acquisition (NVA) mode. Six radiophotoluminescent dosemeters were placed on the head of a RANDO phantom. The doses absorbed by the organs and image noise change rate were determined. The lens doses without OEM (i.e. in the OEMoff case) were higher than those with the same target standard deviation and volume-computed tomography dose index (CTDIvol) as in the OEMoff case (p < 0.01). The image noise change rate was 11%. OEM reduced the lens dose during head 4D CT imaging in the NVA mode by 18%. Furthermore, the feasibility of lens dose reduction while ensuring sufficient image quality was confirmed under the condition in which OEM was employed with the same CTDIvol as in the OEMoff case.

Strategy to Reduce the Collective Equivalent Dose for the Lens of the Physician's Eye Using Short Radiation Protection Curtains to Prevent Cataracts.

A short curtain that improves on the low versatility of existing long curtains was developed as a dedicated radiation protective device for the over-table tube fluorographic imaging units. The effect of this short curtain in preventing cataracts was then examined. First, the physician lens dose reduction rate was obtained at the position of the lens. Next, the reduction rate in the collective equivalent dose for the lens of the physician's eye was estimated. The results showed that lens dose reduction rates with the long curtain and the short curtain were 88.9% (literature-based value) and 17.6%, respectively, higher with the long curtain. In our hospital, the reduction rate in the collective equivalent dose for the lens of the physician's eye was 9.8% and 17.6% with a procedures mixture, using the long curtain where technically possible and no curtain in all other procedures, and the short curtain in all procedures, respectively, higher with the short curtain. Moreover, a best available for curtains raised the reduction rate in the collective equivalent dose for the lens of the physician's eye a maximum of 25.5%. By introducing the short curtain, it can be expected to have an effect in preventing cataracts in medical staff.

A multicenter study of radiation doses to the eye lenses of clinical physicians performing radiology procedures in Japan.

PURPOSE: We investigated occupational dose to the lens of the eye for physicians engaged in radiology procedures. We evaluated the potential for compliance with the new-equivalent dose limits to the lens of the eye. Further, a "multiple radiation protection" protocol was proposed according to the basic principles of occupational health, and its effectiveness was estimated. METHODS: Physicians engaged in radiology procedure at medical facilities in Japan were included in this study. The eye lens dose (3-mm dose equivalent: Hp (3)) for each participant was measured using a small radio-photoluminescence glass dosimeter mounted on lead glasses. Physicians were directed to procedure multiple radiation protection measures to evaluate their usefulness. RESULTS: The Hp (3) was reduced by multiple radiation protection in all physicians. In particular, the Hp (3) reduced from 207.7 to 43.2 µSv/procedure and from 21.6 to 10.2 µSv/procedure in cardiovascular internal physician and cerebrovascular physician, respectively, after the implementation of the proposed multiple radiation protection measures. The dose reduction rate of these measures was 53% (range: 37%-79%). CONCLUSIONS: The radiation doses received by the eye lenses of physicians engaged in radiology procedure may exceed the dose limits to the lens of the eye if radio-protective equipment and imaging conditions are not properly controlled. However, based on the lens equivalent dose data, the implementation of "multiple radiation protection" according to the basic principles of occupational health can ensure compliance with the new-equivalent dose limits to the lens of the eye without placing an undue burden on individual physicians or medical facilities.

Development and assessment of an educational application for the proper use of ceiling-suspended radiation shielding screens in angiography rooms using augmented reality technology.

PURPOSE: An augmented reality (AR) application to help medical staff involved in interventional radiology (IR) learn how to properly use ceiling-suspended radiation shielding screens was created, and its utility was tested from the perspective of learner motivation. METHOD: The distribution of scattered radiation in an angiography room was visualized with an AR application in three settings: when a ceiling-suspended radiation shielding screen is not used (incorrect); when there is a gap between the bottom edge of the shielding screen and the patient's torso (incorrect); and when there is no gap between the bottom edge of the shielding screen and the patient's torso (correct). This AR application was used by 33 medical staff, after which an Instructional Materials Motivation Survey (IMMS) based on the John Keller's ARCS (four categories of Attention, Relevance, Confidence, and Satisfaction) Motivation Model, consisting of 36-items with responses on a 5-point (1-5) Likert scale, was conducted. RESULTS: The overall score was a high 4.67 ± 0.30 (mean ± standard deviation). Physician's scores tended to be lower than those of other medical staff in the categories of Attention, Relevance, and Satisfaction (not statistically significant). CONCLUSIONS: The AR application to learn how to properly use ceiling-suspended radiation shielding screens was highly rated from the perspective of learner motivation.

Occupational radiation dose to the lens of the eye of medical staff who assist in diagnostic CT scans.

PURPOSE: We investigated occupational dose to the lens of the eye for CT-assisting personnel for diagnostic purposes using a radio-photoluminescent glass dosimeter (RPLD) and evaluate compliance with the new equivalent dose limit for the lens of the eye (20 mSv/year). Further, we proposed the implementation of "multiple protective measures" and estimated its effect. METHOD: An eye lens dosimeter clip was developed specifically to attach RPLDs inside radiation safety glasses in an L-shape. Using a total of six RPLDs attached to the radiation safety glasses, the 3-mm dose-equivalent (Hp(3)) to the lens of the eye for medical staff (n = 11; 6 intensive care physicians, 2 pediatricians, 3 radiological technologists) who assisted patients during CT scan for "diagnostic" purpose (n = 91) was measured. We evaluated the dose reduction efficiencies with radiation safety glasses and bag-valve-mask extension tube. We also estimated the protection efficiency with radiation protection curtain introduced in front of the staff's face via the phantom experiment. RESULTS: Without wearing radiation safety glasses, Hp(3) to the lens of the eye was greatest for intensive care physicians (0.49 mSv/procedure; allowing 40 procedures to be performed annually), followed by pediatricians (0.30 mSv/procedure; 66 procedures annually) and radiological technologists (0.28 mSv/procedure; 71 procedures annually). Use of each type of protective tools: radiation safety glasses (0.07-mm-Pb), bag-valve-mask extension tube (20 cm) and radiation protective curtain (0.25-mm-Pb), reduced Hp(3) to the lens of the eye by 51%, 31% and 61%, respectively. CONCLUSION: Intensive care physicians perform most assisted ventilations with the bag-valve-mask during "diagnostic" CT scans, and may exceed the equivalent dose limit for the lens of the eye if radiation safety glasses are not worn. If "multiple protective measures" are implemented, compliance with the equivalent dose limit for the lens of the eye should be achievable without placing significant burdens on physicians or medical institutions.

Optimization of the Maximum Skin Dose Measurement Technique Using Digital Imaging and Communication in Medicine-Radiation Dose Structured Report Data for Patients Undergoing Cerebral Angiography.

Understanding the maximum skin dose is important for avoiding tissue reactions in cerebral angiography. In this study, we devised a method for using digital imaging and communication in medicine-radiation dose structured report (DICOM-RDSR) data to accurately estimate the maximum skin dose from the total air kerma at the patient entrance reference point (Total Ka,r). Using a test data set (n = 50), we defined the mean ratio of the maximum skin dose obtained from measurements with radio-photoluminescence glass dosimeters (RPLGDs) to the Total Ka,r as the conversion factor, CFKa,constant, and compared the accuracy of the estimated maximum skin dose obtained from multiplying Total Ka,r by CFKa,constant (Estimation Model 1) with that of the estimated maximum skin dose obtained from multiplying Total Ka,r by the functional conversion factor CFKa,function (Estimation Model 2). Estimation Model 2, which uses the quadratic function for the ratio of the fluoroscopy Ka,r to the Total Ka,r (Ka,r ratio), provided an estimated maximum skin dose closer to that obtained from direct measurements with RPLGDs than compared with that determined using Estimation Model 1. The same results were obtained for the validation data set (n = 50). It was suggested the quadratic function for the Ka,r ratio provides a more accurate estimate of the maximum skin dose in real time.

[Evaluation of patient dose from diagnostic X-ray using glass badges].

Radiography is used in medical practices based on the principles of justification and optimization. Patients' exposure doses should be kept as low as still allows for image quality that does not disturb the diagnostic processes. To optimize diagnostic radiological procedures, the international commission on radiological protection (ICRP) advocated the establishment of diagnosis reference levels (DRLs) in the new basic recommendation (Publication 103) in 2007 by stating that "The DRL should be expressed as a readily measurable patient-dose-related quantity for the specified procedure." In this context, a simple and standardized dosimetric method is needed to verify the adaptability of a radiation dose to the DRLs. As a measuring instrument that has good availability, high accuracy, and easy operability, we adopted the glass badge system, which has been used for individual exposure dose management. We evaluated the accuracy of the system as a tool of simplified dosimetry of diagnostic X-rays by comparing it to the standard dosimetry of an ionization chamber. In an energy range of 50 to 140 kV for X-ray exposure, the glass badge showed values within 7% of or closer to those measured by the standard ionization chamber. Moreover, the glass badge measurement was independent of the rectification modes of the X-ray tubes. In conclusion, glass badge measurement is feasible for verifying diagnostic X-ray doses in relation to DRLs and can be widely used in hospitals and clinics.