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Technological differences between computed radiography (CR) and digital radiography (DR) systems can influence patient doses and exposure parameters in pelvic x-ray examinations. The presence of radiosensitive organs in the pelvic region underscores the need to optimize these parameters for both CR and DR systems. This prospective study aimed to compare the patient doses and exposure parameters for adult patients undergoing pelvic x-ray examinations using CR and DR systems, based on data from Sri Lanka. The study included data from 56 x-ray examinations, with 25 using CR and 31 using DR. Patient demographic characteristics and exposure parameters (kVp: kilovoltage peak, mAs: tube current-exposure time product) were recorded, and patient doses were measured in terms of the kerma-area product (PKA) using a PKA meter. Despite similar mean weight and body mass index (BMI), the CR systems showed significantly higher mean kVp (7.4%), mAs (16.4%), and PKA (29.7%) than the DR systems (CR - kVp: 73.2, mAs: 37.8, PKA: 2.29 Gy cm2; DR - kVp: 67.8, mAs: 31.6, PKA: 1.61 Gy cm2). The Mann-Whitney U test revealed statistically significant differences in PKA and kVp between the CR and DR systems (p < 0.05). Furthermore, even with lower patient weight and BMI, the mean mAs and PKA in this study were substantially higher than those reported in the literature for both CR and DR systems. These results suggest the need to optimize current mAs settings for the studied hospitals and introduce radiographic system-specific exposure parameters and reference dose levels for pelvic x-ray examinations in order to enhance patient protection.

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The goal of our study was to clarify the effect of low pulse rate fluoroscopy applying in percutaneous coronary intervention (PCI) on devices' visibility and radiation dose. Four types of fluoroscopy conditions combined with two pulse rates (7.5 and 15 pulses/s) and two types of adaptive temporal filters (ATFs) (weak and strong) were used. Samples for visibility evaluation were acquired with moving phantom and devices such as stent, balloon, and guidewire. Trailing artifacts and the visibility of stent were evaluated by Scheffe's method of paired comparisons. Incident air kerma (Ka,r) and kerma area product (PKA) in the clinic were obtained under two fluoroscopic pulse rate conditions (7.5 and 15 pulses/s). As a result, in 7.5 pulses/s fluoroscopy, trailing artifacts were decreased by using weak ATF with the median value of PKA and Ka,r reduced by about 50%, but stent visibility was decreased compared to 15 pulses/s. Therefore, a combination of 7.5 pulses/s fluoroscopy and suitable ATF can bring dose reduction with avoiding trailing artifacts, but dose per pulse should be adjusted to maintain the stent visibility.

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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.

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Diagnostic reference levels (DRLs) and achievable doses (ADs) provide guidance to optimise radiation doses for patients undergoing medical imaging procedures. This multi-centre study aimed to compare institutional DRLs (IDRLs) across hospitals, propose ADs and multi-centric DRLs (MCDRLs) for four common x-ray examinations in Sri Lanka, and assess the potential for dose reduction. A prospective cross-sectional study of 894 adult patients referred for abdomen anteroposterior (AP), kidney-ureter-bladder (KUB) AP, lumbar spine AP, and lumbar spine lateral (LAT) x-ray examinations was conducted. Patient demographic information (age, sex, weight, BMI) and exposure parameters (tube voltage, tube current-exposure time product) were collected. Patient dose indicators were measured in terms of kerma-area product (PKA) using a PKAmeter. IDRLs, ADs, and MCDRLs were calculated following the International Commission on Radiological Protection guidelines, with ADs and MCDRLs defined as the 50th and 75th percentiles of the median PKAdistributions, respectively. IDRL ranges varied considerably across hospitals: 1.42-2.42 Gy cm2for abdomen AP, 1.51-2.86 Gy cm2for KUB AP, 0.83-1.65 Gy cm2for lumbar spine AP, and 1.76-4.10 Gy cm2for lumbar spine LAT. The proposed ADs were 1.82 Gy cm2(abdomen AP), 2.03 Gy cm2(KUB AP), 1.27 Gy cm2(lumbar spine AP), and 2.21 Gy cm2(lumbar spine LAT). MCDRLs were 2.24 Gy cm2(abdomen AP), 2.40 Gy cm2(KUB AP), 1.43 Gy cm2(lumbar spine AP), and 2.38 Gy cm2(lumbar spine LAT). Substantial intra- and inter-hospital variations in PKAwere observed for all four examinations. Although ADs and MCDRLs in Sri Lanka were comparable to those in the existing literature, the identified intra- and inter-hospital variations underscore the need for dose reduction without compromising diagnostic information. Hospitals with high IDRLs are recommended to review and optimise their practices. These MCDRLs serve as preliminary national DRLs, guiding dose optimisation efforts by medical professionals and policymakers.

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Diagnostic reference levels (DRLs) are a pivotal strategy to be implemented since pediatric interventional cardiology procedures are increasing. This work aimed to propose an initial set of Brazilian DRLs for pediatric interventional diagnostic and therapeutic (D&T) procedures. A retrospective study was carried out in four Brazilian states, distributed across the three regions of the country. Data were collected from pediatric patients undergoing cardiac interventional procedures (CIPs), including their age and anthropometric characteristics, and at least four parameters (number of images, exposure time, air kerma-area product-PKA, and cumulative air kerma). Data from 279 patients undergoing CIPs were gathered (147 diagnostic and 132 therapeutic procedures). There were no significant differences in exposure time and the number of images between the D&T procedures. A wide range of PKA was observed when the therapeutic procedures were compared to diagnostics for all age groups. There were significant differences between the D&T procedures, whether grouping data by patient weight or age. In terms of cumulative air kerma, it was noted that no value exceeded the level to trigger a monitoring process for patients. This study shows that it is possible to adopt them as the first proposal to establish national DRLs considering pediatric patient groups.

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PURPOSE: National diagnostic reference levels in Japan 2020 (DRLs 2020) have been published. In the field of angiography, in addition to the fluoroscopic dose rate, incident air kerma at the patient entrance reference point displayed on the equipment (Ka,r: mGy) and air kerma-area product displayed on the equipment (PKA: Gycm2) were set. A questionnaire survey was conducted at each facility in the Tokai region to confirm the status of medical radiation dose control in the region. METHOD: A questionnaire survey was conducted at each facility in the Tokai region. The items were fluoroscopic dose rate in each area (head and neck, cardiac, chest and abdomen, and limbs), DA and DSA dose rates, and dose area product meter (Ka,r, PKA) for the main procedures in each area. RESULT: The median values in this study were lower than those in the DRLs 2020, indicating that appropriate dose control is being implemented in the Tokai region. The trends of fluoroscopic and radiographic dose rates were different in each area, and there was some variation among the facilities. CONCLUSION: We believe that the incorporation of fluoroscopic and radiographic dose rates by area into the DRLs will facilitate more appropriate dose control at each facility in the future.

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The aim of this work was to propose a preliminary local diagnostic reference levels (DRL) for pediatric interventional cardiology (PIC) procedures in Argentina, for different ranges of age and weight. This work has been conducted in the framework of the "Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean" (OPRIPALC) program coordinated by the World Health Organization and the Pan American Health Organization in cooperation with the International Atomic Energy Agency to ensuring that radiation exposures of pediatric patients are the minimum necessary during fluoroscopy-guided interventional procedures. The local DRL values presented in this paper by weight group and age group were 7.1 Gy·cm2 (<5 kg), 10.7 Gy·cm2 (5-15 kg), 18.0 Gy·cm2 (15-30 kg), 15.9 Gy·cm2 (30-50 kg), and 28.2 Gy·cm2 (50-80 kg) and 5.3 Gy·cm2 (<1), 11.2 Gy·cm2 (1 to 5<), 19.6 Gy·cm2 (5 to 10<), and 21.4 Gy·cm2 (10 to 16<), respectively. Our dose results are among the values found in other international studies; however, there is great potential for dose optimization.

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Effective dose is sometimes used to compare medical radiation exposure to patients and natural radiation for providing explanations about radiation exposure to patients, but its calculation is lengthy and requires dedicated measuring devices. The purpose of this study was to identify the most suitable conversion coefficient for conversion of easily measurable dose to effective dose in posterior-anterior chest radiography, and to evaluate its accuracy by direct measurement. We constructed an examination environment using Monte Carlo simulation, and evaluated the variation in conversion coefficients from incident air kerma (IAK), entrance-surface air kerma (ESAK), and air kerma-area product (KAP) to effective dose when the irradiation field size and radiation quality were changed. Effective doses were also measured directly using thermoluminescence dosimeters and compared with the effective dose obtained from conversion coefficients. The KAP conversion coefficient most effectively suppressed the effect of irradiation field size, and was then used to set conversion coefficients for various half-value layers. The optimal conversion coefficient was 0.00023 [mSv/(mGy·cm2)] at 120 kVp (half-value layer = 5.5 mmAl). Evaluation of the direct measurements obtained with various radiation qualities revealed that the accuracy of the conversion coefficient was maintained at ≤ 11%. The proposed conversion coefficient can be easily calculated even in facilities that do not have equipment for measuring effective dose, and might enable the use of effective dose for providing explanations about radiation exposure to patients.

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The goal of the present study was to propose the first local diagnostic reference levels (DRLs) for interventional pediatric cardiology procedures in a large hospital in Colombia. The data collection period was from April 2020 to July 2022. The local DRLs were calculated as the 3rd quartile of patient-dose distributions for the kerma-area product (Pka) values. The sample of collected clinical procedures (255) was divided into diagnostic and therapeutic procedures and grouped into five weight and five age bands. The Pka differences found between diagnostic and therapeutic procedures were statistically significant in all weight and age bands, except for the 1-5-year age group. The local DRLs for weight bands were 3.82 Gy·cm2 (<5 kg), 7.39 Gy·cm2 (5-<15 kg), 19.72 Gy·cm2 (15-<30 kg), 28.99 Gy·cm2 (30-<50 kg), and 81.71 Gy·cm2 (50-<80 kg), respectively. For age bands, the DRLs were 3.97 Gy·cm2 (<1 y), 9.94 Gy·cm2 (1-<5 y), 20.82 Gy·cm2 (5-<10 y), 58.00 Gy·cm2 (10-<16 y), and 31.56 Gy·cm2 (<16 y), respectively. In conclusion, when comparing our results with other existing DRL values, we found that they are similar to other centers and thus there is scope to continue optimizing the radiation dose values. This will contribute to establishing national DRLs for Colombia in the near future.

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The establishment of diagnostic reference levels (DRLs) is an effective tool for optimising radiation doses delivered to patients during medical imaging procedures. This study aimed to compare the institutional DRLs (IDRLs) and propose a multi-centric diagnostic reference level (MCDRL) for chest x-ray examinations in adult patients in Sri Lanka. A prospective cross-sectional study was conducted with 1091 adult patients across six major tertiary care hospitals. Data on patient characteristics, such as age, sex, weight, and body mass index, and exposure parameters, such as tube voltage (kVp) and the product of tube current and exposure time (mAs), were collected. Patient doses were measured in terms of kerma-area product (PKA) using a PKAmeter mounted on the collimator of the x-ray tube. IDRLs were computed for each hospital according to the International Commission on Radiological Protection guidelines, and the 75th percentile PKAwas used to propose the MCDRL. The relationship between patient weight and exposure parameters was examined using Spearman's rank correlation to investigate the radiographic practice among hospitals. Results showed that IDRLs varied from 0.10 to 0.26 Gy cm2. The proposed MCDRL was 0.23 Gy cm2, substantially higher than the recently published DRLs from other countries. The median kVp ranged from 95 to 104, while mAs ranged from 2.5 to 5.6. Large variations in the PKAand exposure parameters were observed within and among hospitals. The elevated PKAvalues observed in this study were mostly due to the use of high mAs in clinical practice. The weak correlation observed between patient weight and exposure parameters suggests the need to standardise examination protocols concerning patient size. The observed dose variations demonstrate the need for the establishment of national DRLs. Until then, the proposed MCDRL can be considered as the benchmark dose level for chest x-ray examinations in Sri Lanka.

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The purpose was to investigate air-kerma area product (PKA) and entrance surface air-kerma rate ([Formula: see text]a,e) on the effect of the shape of automatic dose rate control (ADRC) in the presence of a wedge compensation filter. We compared and evaluated the variability of the X-ray output using a combination of wedge compensation filters and the ADRC. Two ADRC shapes (round and square) and three poly-methyl-methacrylate thicknesses (15, 20, and 25 cm) were used. A wedge compensation filter was inserted 2 cm at a time, up to 6 cm. When the wedge compensation filter was inserted to 6 cm for 20 cm of poly-methyl-methacrylate, the X-ray output fluctuated significantly. The PKA was reduced by 39% when the wedge compensation filter was inserted to 6 cm and by 59% when it was inserted to 4 cm under round-type for 20 cm poly-methyl-methacrylate. The shape of the ADRC affects [Formula: see text]a,e and PKA.

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BACKGROUND: Fluoroscopy-guided diagnostic and interventional cardiology (IC) procedures help to identify and treat several problems associated with the heart. However, these procedures expose patients, cardiologists, radiographers, and nurses to radiation doses. Due to the risk that ionizing radiation poses, concerns have been raised and studies are continually being done to ensure that optimization is achieved during such procedures. This study assessed patient radiation dose during diagnostic and interventional cardiology procedures as well as right heart studies at a tertiary hospital in Ghana to formulate the facility's diagnostic reference levels (DRLs) for optimization purposes. As this study was the first of its kind in Ghana, it was a vital step towards dose optimization within the local department, as well as contributing to future DRLs in Ghana. METHODS: The study collected dose (air kerma, and kerma area product (KAP) and procedural data, and assessed any correlation between parameters such as fluoroscopy time and KAP, and between body mass index (BMI) and KAP. The DRL values were determined as the 75th percentile level for the dose distribution for the various IC procedures including percutaneous coronary interventions (PCI), coronary angiography (CA), and right heart catheterization (RHC). Data were analyzed using SPSS version 23. RESULTS: CA was the most frequently performed IC procedure (77.3%), while RHC was the least recorded (3.3%). The highest mean KAP was observed during the PCI procedure. The proposed diagnostic reference levels (DRLs) were 162.0 Gy.cm2 (PCI), 69.4 Gy.cm2 (CA), 39.8 Gy.cm2 (RHC) and 159.9 Gy.cm2 (CA+PCI). Patients who presented for the CA+PCI and RHC procedures received the highest and lowest mean KAP of 159.9 Gy.cm2 and 39.8 Gy.cm2 of radiation respectively. CONCLUSION: This study, therefore, concludes that there is a need for dose optimization of radiation exposures for IC procedures at the cardiothoracic center in Ghana.

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PURPOSE: The purpose of this study was to evaluate the accuracy of incident air kerma (Ka,r) and air kerma-area product (PKA) displayed on over-couch-type X-ray fluoroscopic systems by comparing them with the measured values. METHODS: An ionizing chamber was placed at the patient entrance reference point to measure the Ka,r. The PKA was calculated by multiplying the Ka,r by the irradiation area. These measured values were compared with the displayed values. RESULTS: The differences between measured and displayed Ka,r and PKA were less than ±35%, which was the criteria of the Japanese Industrial Standards (JIS). However, the accuracy of the displayed values differed depending on the manufacturer and the device. CONCLUSION: Although no error exceeding the JIS criteria was observed, it is necessary to understand the characteristics of the X-ray fluoroscopic systems related to displayed dose and to manage the systems by performing dose measurements periodically.

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The present study was conducted as part of a comprehensive work to establish National Diagnostic Reference Levels (NDRLs) in Sri Lanka for the first time. DRLs can be used as an effective optimization tool for identifying unusually high or low patient doses during X-ray examinations. This study aims to propose institutional DRLs (IDRLs) by measuring the kerma-area product (KAP) of adult patients undergoing routine projection X-ray examinations. The median and the 75th percentile KAP values obtained were compared with that of the single institution KAP values reported from India and Greece. This descriptive cross-sectional study was conducted in a public hospital in Uva province, Sri Lanka, with 400 adult patients aged 18-87 years and weighing 58 ± 20 kg. The patient-specific information (age, sex, weight, and height) and corresponding exposure parameters (tube voltage and current-exposure time product) were obtained. The KAP values were measured, and descriptive statistics were utilized for data analysis. The median KAP values obtained were proposed as IDRLs. The IDRLs in Gy.cm2 were 0.23 for cervical spine anterior-posterior (AP), 0.19 for cervical spine lateral (LAT), 0.10 for chest posterior-anterior (PA), 0.06 for knee joint AP, 0.05 for knee joint LAT, 1.47 for KUB AP, 0.85 for lumbar spine AP, 1.97 for lumbar spine LAT, 0.29 for shoulder joint AP, 0.61 for skull PA, and 0.60 for skull LAT examinations. The maximum to minimum ratio of KAP values ranged from 2.4 for KUB AP to 6.3 for the cervical spine AP examinations. The median and the 75th percentile of most of the examinations were comparable to corresponding KAP values reported by the countries mentioned above, except for the skull PA and LAT examinations. Accordingly, interquartile ranges of exposure parameters are recommended for skull examinations to improve the optimization of patient doses.

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The goal of the present study was to propose a set of preliminary regional diagnostic reference levels (DRLs) for pediatric interventional cardiology (IC) procedures in Latin America and the Caribbean countries, classified by age and weight groups. The study was conducted in the framework of the Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean program coordinated by the World Health Organization and the Pan American Health Organization in cooperation with the International Atomic Energy Agency. The first step of the program was focused on pediatric IC. Dose data from diagnostic and therapeutic procedures were collected between December 2020 and December 2021. Regional DRLs were set as the third quartile of patient dose data (kerma area product) collected in 18 hospitals from 10 countries in an initial sample of 968 procedures. DRLs were set for four age bands and five weight ranges. The values obtained for the four age bands (<1 yr, 1 to <5 yr, 5 to <10 yr and 10 to <16 yr) were 2.9, 6.1, 8.8 and 14.4 Gy cm2for diagnostic procedures, and 4.0, 5.0, 10.0 and 38.1 Gy cm2for therapeutic procedures, respectively. The values obtained for the five weight bands (<5 kg, 5 to <15 kg, 15 to <30 kg, 30 to <50 kg and 50 to <80 kg) were 3.0, 4.5, 8.1, 9.2 and 26.8 Gy cm2for diagnostic procedures and 3.7, 4,3, 7.3, 16.1 and 53.4 Gy cm2for therapeutic procedures, respectively. While initial data were collected manually as patient dose management systems (DMSs) were not available in most of the hospitals involved in the program, a centralized automatic DMS for the collection and management of patient dose indicators has now been introduced and is envisaged to increase the sample size. The possibility of alerting on high dose values and introducing corrective actions will help in optimization.

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The aim of this systematic review is to undertake a critical appraisal of the evidence in the published literature concerning the conversion factors between kerma-area product (PKA) and effective/organ dose (DCED_PKA, DCHT_PKA) for cardiac interventional fluoroscopy procedures performed in adults and paediatric patients and to propose reference conversion factors to help standardize dose calculations. A search strategy utilizing MeSH headings in three databases identified 59 (adult) and 37 (paediatric) papers deemed eligible for the review. Exclusion criteria were adopted to select data only from publications which established DCED_PKAin patients using the ICRP 103 tissue weighting factors. A time restriction from January 2007 was introduced in the search to capture the evolving trends of utilization of fluoroscopy-guided intervention technologies only in recent years. The suggested DCED_PKAand DCHT_PKAwere synthesized by calculating the weighted averages of the values reported by the authors with weights corresponding to the study sample size. Eighteen studies for both adult (9) and paediatric (9) patients matching the search terms fulfilled the inclusion criteria. The suggested value for DCED_PKAin adult patients amounts to 0.24 mSv Gy-1cm-2. The suggested values for DCHT_PKAranged from a minimum of 0.15 mSv Gy-1cm-2for the female breast to a maximum of 0.97 mSv Gy-1cm-2for the lungs. The suggested values for DCED_PKAin paediatric patients ranged from 3.45 mSv Gy-1cm-2for the new-born to 0.49 mSv Gy-1cm-2in the 15 years age class. The suggested values for DCHT_PKAranged from a minimum of 0.33 mSv Gy-1cm-2for bone marrow in the 15 years age class to a maximum of 11.49 mSv Gy-1cm-2for the heart in the new-born. To conclude, values of DCED_PKA/DCHT_PKAwere provided for calculating effective/organ doses in cardiac interventional procedures. They can be useful for standardizing dose calculations, hence for comparison of the radiation detriment from different imaging procedures and in the framework of epidemiologic studies.

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BACKGROUND: Diagnostic reference levels (DRLs) are required to optimize medical exposure. However, data on DRLs for interventional fluoroscopic procedures are lacking, especially in gastroenterology. This study aimed to prospectively collect currently used radiation doses and help establish national DRLs for fluoroscopy-guided gastrointestinal procedures in Japan. METHODS: This multicentre, prospective, observational study collected actual radiation dose data from endoscopic retrograde cholangiopancreatography (ERCP), interventional endoscopic ultrasound (EUS), balloon-assisted enteroscopy (BAE), enteral metallic stent placement, and enteral tube placement from May 2019 to December 2020. The study outcomes were fluoroscopy time (FT: min), air kerma at the patient entrance reference point (Ka,r: mGy), air kerma area product (PKA: Gycm2), and radiation dose rate (RDR: mGy/min). Additionally, the basic settings of fluoroscopy equipment and the factors related to each procedure were investigated. This study was registered in the UMIN Clinical Trial Registry (UMIN 000036525). FINDINGS: Overall, 12959 fluoroscopy-guided gastrointestinal procedures were included from 23 hospitals in Japan. For 11162 ERCPs, the median/third quartile values of Ka,r (mGy), PKA (Gycm2), and FT (min) were 69/145 mGy, 16/32 Gycm2, and 11/20 min, respectively. Similarly, these values were 106/219 mGy, 23/41 Gycm2 and 17/27 min for 374 interventional EUSs; 53/104 mGy, 16/32 Gycm2 and 10/15 min for 523 metallic stents; 56/104 mGy, 28/47 Gycm2, and 12/18 min for 599 tube placements; and 35/81 mGy, 16/43 Gycm2 and 7/15 min for 301 BAEs, respectively. For the overall radiation dose rate, the median/third quartile values of RDR were 5.9/9.4 (mGy/min). The RDR values at each institution varied widely. INTERPRETATION: This study reports the current radiation doses of fluoroscopy-guided gastrointestinal procedures expressed as DRL quantities. This will serve as a valuable reference for national DRL values. FUNDING: This work was supported by a clinical research grant from the Japanese Society of Gastroenterology.

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Objective@#To investigate the reference level of surface radiation dose of digital radiography (DR) among adult examinees in Beilun District, Ningbo City, so as to provide insights into the optimization of the parameters of DR systems and rational management of the radiation dose.@*Methods@#Based on the cloud imaging system covering 14 DR systems in 11 public hospitals in Beilun District, the diagnosis of adults receiving DR and DR systems check were collected from May 2020 to April 2021. The air kerma-area product ( PKA ) was selected as a measure, and the local diagnostic reference level ( LDRL ), the regional median dose ( RMD ), the regional lowest dose predicted level ( LDPL ) and the typical dose in the DR imaging room were defined using the quartile method according to the examination site, projection direction and radiography positions. The PKA value was transformed into incident air kerma ( Ka, e ), and compared with the recommended value in the Requirements for Radiological Protection in Diagnostic Radiology ( GBZ 130-2020 ).@*Results@#DR was performed among 133 065 person-times from May 2020 through April 2021 in Beilun District. The greatest RMD was found on abdomen AP DR in the supine position ( 120 μGy·m2 ), and the lowest RMD was seen on chest PA DR in the standing position ( 17 μGy·m2 ). The maximums of typical dose in the DR imaging room on chest PA ( 33 vs. 30 μGy·m2 ), abdomen AP ( 161 vs. 153 μGy·m2 ) and pelvis AP DR ( 164 vs. 162 μGy·m2 ) were greater than LDRL in the supine position, and the minimums of typical dose on chest PA ( 10 vs. 11 μGy·m2 ) and chest LAT DR ( 33 vs. 34 μGy·m2 ) were lower than LDPL in the standing position. Following transformation into Ka, e, the LDRL ranged from 0.27 to 3.80 mGy, and the maximums of typical dose ranged from 0.25 to 3.55 mGy, which was much lower than the recommended dose proposed in the national criteria.@*Conclusions@#The reference level of surface radiation dose of DR is established among adults in Beilun District, which is lower than the recommended dose in the national criteria of China. Such a reference level may be employed by medical institutions for optimization of the parameters of DR systems. Key words： digital radiography radiation dose diagnostic reference level air kerma-area product

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The purpose of this study was to establish a simple measurement method to verify the accuracy of incident air kerma (Ka, r) and air kerma area product (PKA) displayed on an over-couch-type X-ray fluoroscopy system. A dosimeter was located at the patient entrance reference point, and the irradiation field size was set to 10×10 cm. A lead plate was placed on the couchtop to protect the image receptor, and the duration of fluoroscopy was set to 1 min. The Ka, r was measured with the proposed method and the Japanese Industrial Standards (JIS) method on three X-ray fluoroscopy units of different manufactures. The effect of backscattered X-rays from the lead plate was calculated using Monte Carlo methods. The errors of the displayed Ka, r and PKA to the measured Ka, r and PKA with our proposed method were calculated. There was no significant difference in the measured Ka, r between the proposed method and the JIS method in all units. The effect of backscattered X-ray was ≤0.5%. The errors of displayed Ka, r and PKA to those measured were in the range of 3.4 to 15.7% and -4.1 to 20.3%, respectively, which met the tolerance for accuracy of ±35% in accordance with the JIS method. We found that our proposed method was simple and that the accuracy of measured values was comparable to that of the JIS method.

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PURPOSE: This study aimed to evaluate the effect of equalization filters (EFs) on the kerma-area product ( K A P Q K M ) and incident air-kerma ( K a , i , Q K M ) using a kerma-area product (KAP) meter. In addition, potential underestimations of the K a , i , Q K M values by EFs were identified. MATERIALS AND METHODS: A portable flat-panel detector (FPD) was placed to measure the X-ray beam area (A) and EFs dimension at patient entrance reference point (PERP). Afterward, a 6-cm3 external ionization chamber was placed to measure incident air-kerma ( K a , i , Q e x t ) at PERP instead of the portable FPD. KAP reading and K a , i , Q e x t were simultaneously measured at several X-ray beam qualities with and without EFs. The X-ray beam quality correction factor by KAP meter ( k Q , Q 0 K M ) was calculated by A, K a , i , Q e x t and KAP reading to acquire the K A P Q K M and K a , i , Q K M . Upon completion of the measurements, K A P Q K M , K a , i , Q K M , and K a , i , Q e x t were plotted as functions of tube potential, spectral filter, and EFs dimension. Moreover, K a , i , Q K M / K a , i , Q e x t values were calculated to evaluate the K a , i , Q K M underestimation. RESULTS: The k Q , Q 0 K M values increased with an increase in the X-ray tube potential and spectral filter, and the maximum k Q , Q 0 K M was 1.18. K A P Q K M and K a , i , Q K M decreased as functions of EFs dimension, whereas K a , i , Q e x t was almost constant. K a , i , Q K M / K a , i , Q e x t decreased with an increase in EFs dimension but increased with an increase in tube potential and spectral filter, and the range was 0.55-1.01. CONCLUSIONS: K a , i , Q K M value was up to approximately two times lower than the K a , i , Q e x t values by EFs. When using the K a , i , Q K M value, the potential K a , i , Q K M underestimation with EFs should be considered.

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