[Multicenter Survey on Phantom Entrance Surface Air Kerma of Angiography and IVR in Japan].

PURPOSE: In DRLs 2020, the entrance surface air kerma (Ka,e) was set to 17 mGy/min as the reference dose rate in fluoroscopy. But, Ka,e in fluoroscopy for different regions and Ka,e in exposure was not set. A multicenter survey was conducted to evaluate Ka,e by each area. METHODS: Ka,e for each area was analyzed for 79 facilities attending this survey (274 machines and 461 protocols). When the protocols were changed by the difference in disease, angiography, or IVR, the difference rate of Ka,e was evaluated. Ka,e before and after modifying the incident air kerma at the patient entrance reference point (Ka,r) and air kerma area product (PKA) difference rate were calculated when protocols were changed, considering the DRLs 2020. RESULTS: There were dose differences in Ka,e by each area. Compared to DRLs 2020, 36 protocols from 13 facilities modified their protocols, all of which reduced Ka,e. CONCLUSION: Although reducing Ka,e does not necessarily reduce Ka,r, and PKA, comparison of Ka,e by each area is expected to optimize medical exposure protection, including evaluation of quality control.

[Development of Dose Calculation Application for Computed Tomography Dose Management When Facility Protocols Differ from Diagnostic Reference Level (DRL)].

PURPOSE: In this study, we aimed to develop an application that computes dose values resembling diagnostic reference level (DRL) conditions when disparity prevents direct dose comparisons between the national diagnostic reference levels in Japan 2020 (Japan DRLs_2020) and facility-specific computed tomography (CT) protocols. METHODS: We developed an application using the R programming language and RStudio software that computes dose values and median values based on Japan DRLs_2020 imaging conditions following extraction of necessary information for dose calculations from the Radiation Dose Structured Report (RDSR) and Digital Imaging and Communications in Medicine (DICOM) tags. To ensure a user-friendly experience, we used the Shiny package to develop a graphical user interface that enables the application to operate seamlessly in web browsers. RESULTS: The developed application successfully facilitated the calculation of dose and median values that aligned with the Japan DRLs_2020 for protocols whose imaging range and acquisition timing differed from those of the Japan DRLs_2020. CONCLUSION: By calculating dose values that align with DRL conditions, our application contributes to the implementation and optimization of dose management in CT for facilities that use diverse imaging protocols.

Data analysis of average glandular dose in mammography toward revision of the diagnostic reference level of Japan.

Diagnostic reference level (DRL) for mammography for 2015 and 2020 has been published by J-RIME. More new dose studies are needed to revise the next DRL. In preparation for the next revision of the DRL for mammography, this study investigated data from the Japan Central Organization on Quality Assurance of Breast Cancer Screening on the mean average glandular dose (AGD) for institutional image accreditation in 2019-2023 and the relationship between the average at eligible institutions to date and the type of breast X-ray system. The 95th percentile values of the AGD distributions for the Computed Radiography (CR) and Flat Panel Detector (FPD) systems were 2.5 mGy and 2.0 mGy, respectively. Moreover, it is assumed that AGD is decreasing due to the spread of FPD systems, and it is expected that the further spread of FPD systems and systems with W/Rh target/filter will reduce AGD in future.

An audit of patient radiation doses during interventional cardiology procedures in Uttarakhand, India, and establishment of local diagnostic reference levels.

The objective of this study was to investigate patient radiation doses by a dose audit of three common interventional cardiology (IC) procedures: coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA) and CA-PTCA procedures performed in IC centres in the Uttarakhand state of India, for the establishment of local diagnostic reference levels (DRLs) and the estimation of average effective dose (Eav) for these procedures. For each procedure, the values of kerma-area product (PKA), reference air kerma (Ka,r), fluoroscopy time (FT) and the number of cine images were recorded from 1233 CA, 458 PTCA and 736 CA-PTCA procedures performed over a 12-month period at 13 IC centres of the state. From the recorded dose data, 0.6%, 1.53% and 7.9% patients were identified to have exceeded the PKA trigger level of 500 Gy cm2 for possible skin injury for CA, PTCA and CA-PTCA procedures, respectively. The 3rd quartile of the distribution of the recorded PKA values for each type of procedure was calculated to estimate local DRL values. The estimated values of DRLs and Eav were 37, 153 and 224 Gy cm2, and 6.72, 23.97 and 34.79 mSv for CA, PTCA and CA-PTCA procedures, respectively. For about 77% of the surveyed centres, the recorded patient doses were in agreement with the international standards. The local DRLs proposed in this study may be used to achieve patient dose optimization during IC procedures and the obtained patient dose data may also be archived into national dose database for the establishment of national DRLs.

[Development of a X-ray Exposure Dose Control Tool for CT Examination by Using Spreadsheet Software].

PURPOSE: We developed X-ray dose monitoring and optimization software for computed tomography (CT) by using a spreadsheet software. METHODS: The analysis was carried out on 1,212 patients using 2,128 CT examinations at our institution, in the period of April 2020 to April 2022. These cases were extracted in the limitation of patient's weight in the range of 50 to 70 kg. The individual radiation report, including CTDIvol and DLP, on the console displayed by a CT system was used and manually transferred to our software. The X-ray dose distribution was evaluated by using a boxplot chart and a scatter plot, and the data were referred to Japan DRLs 2020 (National Diagnostic Reference Levels in Japan 2020). RESULTS: Almost all patient's doses in our institution were distributed in the acceptable ranges in comparison with the Japan DRLs 2020. Neither extremely high nor low dose data were recorded. However, seven cases recorded outlier dose values. Three cases were caused by errors during manually inputting the data. Four from seven cases were explored the reason to record outlier dose values. CONCLUSION: Our software on a spreadsheet software worked well to explore the CT dose data, such as CTDIvol and DLP. Our software was able to find cases that were recorded as outlier dose values, but their values were not extremely high/low values. The cautionary notice of either high or low dose, as a function of our software, will be able to keep our patient's CT dose in the universal-standard "justification and optimization" level.

Development of acceptable quality radiation dose levels for common computed tomography examinations: A focused multicenter study in United Arab Emirates.

Purpose: Diagnostic Reference Level (DRL) is a practical tool for radiation dose optimization, yet it does not indicate the patient size or image quality. The Acceptable Quality Dose (AQD) introduced to address the limitations of the DRLs and it is based on image quality, radiation dose, and patient weight. The aim of this study is to establish the AQD for adult patients' undergoing Computed Tomography (CT) examinations (Head, chest, abdomen). Methods: This study is conducted in the four main hospitals at the Ministry of Health and Prevention. Patient information and exposure parameters were extracted. All the acceptable images are scored for their quality assessments. Data is classified as seven weight groups, <50, 50-59, 60-69, 70-79, 80-89, 90-99, and ≥100 kg. The mean ± SD, median, and 75th are calculated for the CTDIvol and DLP for each weight group per examination. Results: Out of 392, 358 CT examinations are scored with acceptable quality. The median CTDIvol values for the weight groups are obtained as 24.6, 25.4, 25.4, 25.0, 26.0, 27.0, and 29.0 mGy. Moreover, median DLP values are obtained as 576.7, 601.0, 616.5, 636.1, 654.0, 650.0, 780.0, and 622.5 mGy.cm, respectively, for head CT without Contrast Media (CM). Similar calculation for head CT with (CM), chest without CM, abdomen without CM, and chest and abdomen (with and without CM) CTs are presented. Conclusion: Images with bad, unacceptable and higher than necessary qualities contribute to increasing patient dose and increasing the DRLs. The AQD for the selected examinations were lower than the proposed DRLs in the United Arab Emirates. The integration of image quality and patients size in the assessment of the AQD values provide effective model to compare radiation dose indices within facility and compare with others. The obtained results may be useful in terms of improving dose and the diagnostic quality in the national and international levels.

[Scientific Research Group Report: Nationwide Survey on Radiation Exposure of Pediatric CT Examination in Japan (2018)].

PURPOSE: To understand the latest pediatric computed tomography (CT) exposure required for the revision of national DRLs. METHODS: A questionnaire was sent to 409 facilities where the members of the Japanese Society of Radiological Technology and the Japanese Society of Pediatric Radiology are enrolled. We investigated the imaging conditions, CTDIvol, and DLP of the pediatric head, chest, and abdominal CT examinations. RESULTS: In all, 43 facilities (11%) responded to our survey. multi detector-row CT (MDCT) systems were available in all surveyed facilities. More than 98% of the MDCT systems had more than 64 detector rows. The CTDIvol of all CT protocols was lower than the NDRL due to the progress of updating to MDCTs with radiation exposure reduction functions such as an iterative reconstruction, but the DLP of head and abdominal CT protocols of some age group were higher than NDRL. CONCLUSION: It is necessary to review the imaging protocol with the attending physician and radiologist and consider further optimization of medical exposure.

Chest X-rays of newborns in a medical facility: variation between the entrance skin dose measurements using the indirect and direct methods for clinical dose audit.

PURPOSE: This study aims to determine the mean and 75th percentile entrance skin dose (ESDcal) from anteroposterior (AP) chest X-rays using machine parameters (indirect method). Also, a comparison was made between the ESDcal and already determined thermoluminescent dosimeter (TLD) measurements (ESDTLD) from a previous study from the same patients' data. In addition, the results were compared to similar articles, where the direct and indirect methods were used in estimating ESD to newborns. MATERIALS AND METHODS: The study determined the digital radiography (DR) X-ray machine output using a calibrated XR Multidetector (silicon photodiode). X-ray machine milliampere-seconds (mAs), peak kilovoltage (kVp), focus to detector distance (FDD) and focus to skin distance (FSD) were used from a previous study. The mean kVp and mAs were 56.63 (52-60) and 5.7 (5-6.3) and the patient thickness was 9.5 (8-11.5) cm. RESULTS: The mean ESDs of the newborn between 0 and 28 days were 0.67 ± 0.09 mGy, and the 75th percentile was 0.75 mGy. The effective dose (E) for the 40 patients was 0.19 mSv and the estimated prenatal cancer risk ranged from (5-24.7) 10-6 Sv-1. The variation between the indirect and the direct methods for assessing ESD was 39.6 (33.7-45.1)%. CONCLUSION: The 75th percentile ESD was the highest compared to the American College of Radiology-American Association of Physicists in Medicine-Society for Pediatric Radiology (ACR-AAPM-SPR), European Commission (EC) and United Kingdom (UK) reports. Comparison of both methods for assessing ESD was within 40% as compared to other studies. Based on the above results, the indirect method can be implemented for clinical dose audit.

Measuring the dose-width product and proposing the local diagnostic reference level in panoramic dental radiography: a multi-center study from Iran.

OBJECTIVE: Although radiation exposure associated with dental radiography is relatively low, patient exposure must be kept practically low. Therefore, it is necessary for each country to establish its own diagnostic reference levels (DRLs) suitable for its equipment and practice. In the present study, dose-width product (DWP) values for panoramic dental radiography were measured and a local DRL was established. METHODS: Five panoramic devices from five radiology clinics of Kashan, Iran were selected to measure the DWP values of panoramic dental radiography. To investigate the DWP values, the parameters of each patient's exposure (e.g., tube voltage, tube current, and exposure time) at these five radiology clinics were extracted. Then, the dose value received by each patient was measured based on a CT pencil chamber. Finally, the overall median DWP values for the patients with small, medium, and large sizes were obtained, and these values were considered as the local DRLs for panoramic dental radiography. RESULTS: A total of 99 adult patients were included in the present study. The findings demonstrated that the median and third-quartile DWP values for these five radiology clinics ranged from 42.3 to 94.3 and 49.7 to 142.8 mGy mm, respectively. The local DRL values, which were established as the overall median DWP values, were 43.4, 52.0, and 80.3 mGy  mm for the adults with small, medium, and large sizes, respectively. CONCLUSION: The local DRL proposed in this study for the adult with standard/medium size was lower than those proposed by other reports and seemed acceptable for panoramic radiography in Kashan, Iran.

An audit of radiation doses received by paediatric patients undergoing computed tomography investigations at academic hospitals in South Africa.

BACKGROUND: Diagnostic reference levels (DRLs) are a crucial element of auditing radiation doses in paediatric computed tomography (CT). Currently, there are no national paediatric CT DRLs in South Africa. OBJECTIVES: The aim of this article was to establish local paediatric DRLs for CT examinations at two academic hospitals and to compare paediatric CT radiation output levels with established DRLs in the developed and developing world. METHOD: Computed Tomography Dose Indexvolume (CTDIvol) and dose length product (DLP) values were collected from CT examinations performed at two university hospitals for patients aged 0-15 years, during 01 November 2016-30 April 2017. The 75th percentile of the data distribution was calculated for each CT examination type and age group, further categorised into routine working hours and after-hours for both hospitals and statistically compared. RESULTS: Of the 1031 CT examinations performed, CT brain examination was the most common (755/1031; 72.23%). DLP values were increased in the after-hours categories compared to regular working hours at both hospitals. The largest increase was in the 0-1 year age group (150.56%). With the exception of CT Chest and CT abdomen in the 0-1 year age group, the CTDIvol and DLP values compared favourably to international standards. CONCLUSION: Most of the calculated DRLs are acceptable and internationally comparable. This likely indicates effective reduction techniques and protocols. Computed tomography body examination protocols for 0-1 year patients should be reviewed. Strategies should be implemented to limit higher doses in after-hours examinations.

[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.

[Nationwide Survey of Medical Radiation Exposure on Cardiovascular Examinations in Japan].

PURPOSE: It is very important to manage the radiation dose of cardiovascular interventional (CVI) procedures. Overseas, the diagnostic reference levels for cardiac interventional procedures were established with the air kerma at the patient entrance reference point (Ka,r) and the air kerma-area product (PKA). Although the Japan DRLs 2015 was established by the Japan Network for Research and Information on Medical Exposure (J-RIME), the Japan DRL for CVIs were established by fluoroscopic dose rates of 20 mGy/min at the patient entrance reference point with 20 cm thickness polymethyl methacrylate (PMMA) phantom. In the present our study, we performed a questionnaire survey of indicated values of angiographic parameters in CVI procedures. METHODS: A nationwide questionnaire was sent by post to 765 facilities. Question focused on angiographic technology, exposure parameters and radiation doses as the displayed dosimetric parameters on the angiographic machine. RESULTS: The recovery rate was 22.8% at 175 out of 765 facilities. In total 1728 cases of the coronary angiography (CAG), 1703 cases of the percutaneous coronary intervention (PCI), 962 cases of the radiofrequency catheter ablation (RFCA) and 377 cases of pediatric CVI. The 75th percentile value of Ka,r, PKA, fluoroscopy time (FT) and number of cine images (CI) for CAG, PCI, RFCA and pediatric CVI were 702, 2042, 644, and 159 mGy, respectively, 59.3, 152, 81.3, and 14.9 Gy・cm2, respectively, 10.2, 35.6, 61.1, and 35.6 min, respectively and 1503, 2672, 722, and 2378 images, respectively. Our investigation showed that the angiographic parameters were different in several CVI procedures. CONCLUSIONS: The displayed dosimetric parameters on the angiographic machine in CVI procedures showed different values. We should classify the dosimetric parameters for each procedure.

[Multi-facility Survey on Accuracy and Calibration Method for Dose Area Product Meter of Angiography Systems].

In many facilities, the displayed dose of dose-area product (DAP) is used for the dose management of interventional radiology. In this study, we investigated the measured dose at the patient entrance reference point (interventional reference point) and the displayed dose on each angiography systems. Also, we investigated the calibration method of each DAP. The errors of the measured dose and the displayed dose were less than 35%, but that dispersion was wide between the systems. The calibration methods varies according to a system. And even in the same manufacturer, the calibration methods were different. Therefore, to use the displayed dose of DAP for patient dose management, we need to compare that with the measured dose regularly. The differences of calibration methods induce the wide dispersion of the errors of the measured and the displayed dose. So the standardization of the calibration method in each manufacturer is expected.

Estimation of entrance surface air kerma due to diagnostic X-ray examinations of adult patients in Uttarakhand, India and establishment of local diagnostic reference levels.

It is well established that diagnostic X-ray practices must be optimised to keep patient radiation dose as low as compatible with providing the diagnostic information required. For effective optimisation of diagnostic exposures, the International Commission on Radiological Protection (ICRP) introduced the concept of diagnostic reference levels (DRLs) in 1996. The present study aimed to carry out an extensive dose survey of diagnostic radiography installations in the Uttarakhand region of India to establish local DRL Values for the different diagnostic practices. During the survey, air kerma values were measured for 297 diagnostic X-ray machines installed at 270 medical centres in the region and the entrance surface air kerma (K a,e) was estimated for ten commonly performed radiographic projections. These included chest posterior-anterior (PA), cervical spine anterior-posterior (AP), skull PA, abdomen AP, KUB (kidney, ureter and bladder), lumbar spine AP, lumbar spine lateral (LAT), pelvis AP, thoracic spine AP, and thoracic spine LAT. Wide variations were observed in the estimated values of K a,e for individual projections. The third quartile of the distribution of the median values of the estimated K a,e for a given projection was calculated to establish local DRL Values. The majority of the acquired dose data were found to be comparable to or less than the proposed national and international DRLs. The local DRL Values reported in this study may be used to improve radiological practice by reducing patient doses during radiography examinations. The obtained data may also contribute to a national patient dose database for establishing future national DRLs.

Examination of Dose Reduction Using Image Noise Reduction Technology in Cardiovascular X-ray Systems.

The aim of this study is to establish radiation exposure dose reduction protocols during cardiac intervention by decreasing the entrance dose at flat panel detector (FPD) with image quality evaluations. For measuring entrance surface dose (ESD), we have used a Radical 9015 dosimeter (6 cc ion chamber) placed under 20 cm thick acrylic plates at the patient's entrance reference point. We performed an image quality assessment based on quantitative as well as visual evaluation of the images obtained via current and dose reduction protocols. The visual evaluation was performed by measuring the signal to noise ratio and contrast using a cine/digital angiography cardiac phantom. The quantitative evaluation was performed by cardiologists and radiological technologists using the five-point scale method. For the dose reduction protocol, we used an image noise reduction technique to prevent the deterioration of image quality. The ESDs for the fluoroscopy and digital cine in the dose reduction protocol were 18.0 mGy/min and 0.18 mGy/frame, respectively, which corresponded to 81% and 49% of the ESD in the current protocol. Our results reveal that the ESD for fluoroscopy was lower than the diagnostic reference level (20 mGy/min) for interventional radiology. We recommend a lower dose setting and the maintenance of image quality using noise reduction techniques. This will ensure use of a lower FPD entrance dose compared to the initial dose setting currently recommended by manufacturers.

Establishment of local diagnostic reference levels for quality control in intraoral radiography.

OBJECTIVE: To investigate the dosage and imaging conditions for patients undergoing intraoral radiography at Meikai University Hospital and establish assurance and quality control data. METHODS: Tube voltage, exposure time, and air kinetic energy released per unit mass (air kerma) of three intraoral radiography units were measured. To calculate the patient entrance dose (PED) for each radiograph using Insight film, we extracted data for 1063 patients from their exposure records. The PED was compared with the diagnostic reference level (DRL) from the European Commission and the UK. RESULTS: The tube voltage of the three units was maintained at 60 ± 2 kV. Differences in exposure time were less than 1.7 % for all units. The air kerma rates were well maintained within a 4.2 % error. Based on the patient data, there were no significant differences in the mean exposure times for males and females for all anatomical sites. The mean PED ranged from 1.09 ± 0.31 mGy for the mandibular incisors to 2.42 ± 0.33 mGy for the maxillary molars. The mean PED at the mandibular molars using InSight film was 1.59 ± 0.20 mGy, being less than the recommended value based on the DRL for intraoral radiography in the UK. CONCLUSIONS: We concluded that radiographic conditions at the hospital have been properly maintained. This basic quality control data may assist other dental radiation facilities to reduce patient dosage.