National Diagnostic Reference Levels Research Articles

Establishment of local diagnostic reference levels for computed tomography with cloud-based automated dose-tracking software in Türkiye

The purpose of this study is to establish local diagnostic reference levels (LDRLs) for computed tomography (CT) procedures using cloud-based automated dose-tracking software. The study includes the dose data obtained from a total of 104,272 examinations performed on adult patients (>18 years) using 8 CT scanners over 12 months. The protocols included in our study were as follows: head CT without contrast, cervical spine CT without contrast, neck CT with contrast, chest CT without contrast, abdomen-pelvis CT without contrast, lumbar spine CT without contrast, high-resolution computed tomography (HRCT) of the chest, and coronary CT angiography (CTA). Dose data were collected using cloud-based automatic dose-tracking software. The 75th percentiles of the distributions of the median volume CT dose index (CTDIvol) and dose length product (DLP) values were used to determine the LDRLs for each protocol. The LDRLs were compared with national DRLs (NDRLs) and DRLs set in other countries. Inter-CT scanner variability, which is a measure of how well clinical practices are standardized, was determined for each protocol. Median values for each protocol were compared with the LDRLs for dose optimization in each CT scanner. The LDRLs (for DLP and CTDIvol, respectively) were 839 mGy.cm and 41.2 mGy for head CT without contrast, 530.6 mGy.cm and 19.8 mGy for cervical spine CT without contrast, 431.9 mGy.cm and 15.5 mGy for neck CT with contrast, 364.8 mGy.cm and 9.3 mGy for chest CT without contrast, 588.9 mGy. cm and 11.2 mGy for abdomen-pelvis CT without contrast, 713 mGy.cm and 24.3 mGy for lumbar spine CT without contrast, 326 mGy.cm and 9.5 mGy for HRCT, and 642.3 mGy.cm and 33.4 mGy for coronary CTA. The LDRLs were comparable to or lower than NDRLs and DRLs set in other countries for most protocols. The comparisons revealed the need for immediate initiation of an optimization process for CT protocols with higher dose distributions. Furthermore, protocols with high inter-CT scanner variability revealed the need for standardization. There is a need to update the NDRLs for CT protocols in Turkey. Until new NDRLs are established, local institutions in Turkey can initiate the optimization process by comparing their dose distributions to the LDRLs established in our study. Automated dose-tracking software can play an important role in establishing DRLs by facilitating the collection and analysis of large datasets.

Characterisation of Portuguese radiotherapy departments: Organisation, occupational exposure values and diagnostic reference levels for breast and prostate computed tomography planning

IntroductionPortugal currently hosts 24 active radiotherapy departments, 8 public and 16 privates, presenting potential radiation exposure risks to multidisciplinary teams. Patients in these treatments also face ionising radiation during treatment planning and verification. MethodsAuthorisation and ethical approval were secured for a national online survey, disseminated to radiotherapy departments across Portugal. The survey encompassed three sections: equipment, staff, and radiographer role characterisation; occupational exposure values for one month; and exposure parameters, including computed tomography (CT) dose values [CT dose index (CTDIvol) and dose length product (DLP)] for breast and prostate cancer CT planning. Local Diagnostic Reference Levels (DRLs) derived were based on the 75th percentile of median dose values. ResultsThe study garnered a 50% response rate from public institutions, 12,5% from private and 25% from all active radiotherapy institutions in Portugal. All departments employ Three-Dimensional Conformal Radiation Therapy (3D–CRT) and incorporate Intensity Modulated Radiation Therapy (IMRT) and/or Volumetric Modulated Arc Therapy (VMAT) irradiation techniques. Additionally, half of the departments also perform Brachytherapy (BT). Radiographers demonstrated an occupational dose of zero mSv. CT planning dose values were 13 mGy and 512 mGy cm for breast CT and 16 mGy and 689 mGy cm for prostate CT, pertaining to CTDIvol and DLP, respectively. ConclusionMost aspects of national radiotherapy characterisation align with the established literature. Occupational exposure values exhibited consistency across radiotherapy modalities. An approach to national DRLs was formulated for breast and prostate CT planning, yielding values congruent with recent European studies. Implications for practiceThis study offers vital insights for analysing occupational contexts and risk prevention, serving as the initial characterisation of the national radiotherapy landscape. It also pioneers the calculation of DRLs for CT planning in radiotherapy to optimise procedures.

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.

Age-based diagnostic reference levels and achievable doses for paediatric CT: a survey in Shanghai, China

Computed tomography (CT) is extensively utilised in medical diagnostics due to its notable radiographic superiority. However, the cancer risk associated with CT examinations, particularly in children, is of significant concern. The assessment of cancer risk relies on the radiation dose to examinees. Diagnostic reference levels (DRLs) and achievable doses (ADs) were used to assess the level of radiation dose in CT examinations widely. Although the national DRLs of paediatric CT have been explored in China, few local DRLs at the city level have been assessed. To set up the local DRLs and ADs of paediatric CT, we investigated the radiation dose level for paediatric CT in Shanghai. In this survey, a total of 3061 paediatric CT examinations underwent in Shanghai in 2022 were selected by stratified sampling, and the dose levels in terms of volume CT dose index (CTDIvol) and the dose-length product (DLP) were analysed by 4 age groups. The DRLs and ADs were set at the 75th and 50th percentile of the distribution and compared with the previous studies at home and abroad. The survey results revealed that, for head scan, the DRLs of CTDIvol were from 25 to 46 mGy, and the levels of DLP were from 340 to 663 mGy·cm. For chest, the DRLs of CTDIvol were from 2.2 to 8.3 mGy, and the levels of DLP were from 42 to 223 mGy·cm. For abdomen, the DRLs of CTDIvol were from 6.3 to 16 mGy, and the levels of DLP were from 181 to 557 mGy·cm. The ADs were about 60% lower than their corresponding DRLs. The levels of radiation doses in children-based hospitals were higher than those in other medical institutions (P < 0.001). In conclusion, there was still potential for reducing radiation dose of paediatric CT, emphasising the urgent need for optimising paediatric CT dose in Shanghai.

Prospective dose monitoring using a manual dose management system: experience in brain computed tomography from a tertiary hospital in Nigeria.

A manual radiation dose management system was developed to track the radiation dose and scan parameters of patients for brain computed tomography (CT). Radiation dose in volume computed tomography dose index (CTDIvol) and dose length product (DLP) were monitored to identify procedures that may require optimisation using notification values. The data were analysed and compared with national and international diagnostic reference levels (DRLs). A total of 596 brain CTs were monitored and grouped as <1: 36, 1-<5: 38, 5-<10: 25, 10-<15: 31 and adult: 466. The CTDIvol notification value identified the following number of examinations having high CTDIvol in <1y: 1, 1-<5: 1, 5-<10: 0, 10-<15: 0 and adult (>15): 11. Furthermore, the DLP notification values identified the following examinations with high DLP in <1y: 1, 1-<5:1, 5-<10:1, 10-<15: 1 and adults (>15): 18. The established local paediatric DLP DRLs were 2-3 times higher than the international paediatric DLP DRLs. This calls for a total protocol review and optimisation considering the local CT practices for paediatric imaging.

Towards the establishment of national diagnostic reference levels for abdomen, KUB, and lumbar spine x-ray examinations in Sri Lanka: a multi-centric study

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 PKA meter. 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 PKA distributions, respectively. IDRL ranges varied considerably across hospitals: 1.42–2.42 Gy cm2 for abdomen AP, 1.51–2.86 Gy cm2 for KUB AP, 0.83–1.65 Gy cm2 for lumbar spine AP, and 1.76–4.10 Gy cm2 for 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 PKA were 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.

Local Diagnostic Reference Levels for Adult Computed Tomography Urography Exams.

A Computed Tomography Urography (CTU) scan is a medical imaging test that examines the urinary tract, including the bladder, kidneys, and ureters. It helps diagnose various urinary tract diseases with precision. However, patients undergoing CTU imaging receive a relatively high dose of radiation, which can be a concern. In our research paper, we analyzed the Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP) for 203 adult patients who underwent CTU at one of the most important regional centers in Bosnia and Herzegovina that sees a large number of patients. Our study included the distribution of age and sex, the number of phases within one examination, and different clinical indications. We compared our findings with the results available in the scientific literature, particularly the recently published results from 20 European countries. Furthermore, we established the local diagnostic reference levels (LDRLs) that can help set the national diagnostic reference levels (NDRLs). We believe our research is a significant step towards optimizing the protocols used in different hospitals in our country.

Impact of Implementing National Diagnostic Reference Levels on Radiation Dose Optimization in Adult Chest CT Scans: A Comparative Analysis

The management and optimization of radiation dose in computed tomography (CT) examinations is of paramount importance, especially when the safety of patients is concerned. This study evaluated the effect of implementing national diagnostic reference levels (NDRLs) for radiation dose optimization in 1,991 adult chest CT scans at a major Saudi hospital. Data was analyzed before and after NDRL implementation, with 21.5% of scans using contrast and 78.5% without. Before implementation, 11.1% used contrast and 36.7% did not; after implementation, 10.4% used contrast and 41.7% did not. The majority (83.5%) of scans passed NDRL criteria [CTDIvol and DLP are set at 12 (mGy) and 430 (mGy·cm)], with higher pass rates for contrast (91.8%) versus non-contrast (81.5%) scans. Effective dose (ED) was compared before and after NDRL implementation. For non-contrast scans, ED declined 2.43% from 12.37±5.25 mSv to 12.07±4.99 mSv after implementation (non-significant, p&gt;0.05). For contrast scans, ED declined more substantially, 6.77% from 9.6±4.61 mSv to 8.95±4.44 mSv (non-significant, p&gt;0.05). The findings highlight higher NDRL compliance in procedures with contrast and show areas for dose optimization improvement in procedures without contrast. Results suggest NDRLs provide guidance for optimizing radiation dose, but other factors like patient characteristics, protocol settings, and quality assurance programs should also be considered to ensure doses are as low as reasonably achievable (ALARA) without compromising diagnostic quality. Regular monitoring and review of CT protocols is recommended to avoid unintended consequences of dose reduction. Continued optimization is encouraged to reduce dose while ensuring quality.

Updating national diagnostic reference levels for computed tomography in Greece: Challenges on patient protection optimisation

The escalating use of Computed Tomography (CT) imaging necessitates establishment and periodic revision of Diagnostic Reference Levels (DRLs) to ensure patient protection optimization. This paper presents the outcomes of a national survey conducted from 2019 to 2022, focusing on revising DRLs for adult CT examinations. Dosimetric data from 127 scanners in 120 medical facilities, representing 25% of the country's CT scanners, were collected, emphasizing geographic distribution and technology representation. Τhe parameters used for DRLs were the CTDIvol and the DLP of a typical acquisition of the region of interest (scan DLP). In addition to the 7 CT examination for which the DRL values were revised, establishment of DRLs for neck, cervical spine, pelvic bones-hips, coronary artery calcium (Ca) score and cardiac computed tomography angiography (CCTA) examinations was performed.Revised DRLs exhibited a 15 % average decrease in CTDIvol and a 7 % average decrease in scan DLP from the initial DRLs. This reduction of dosimetric values is relatively low compared to other national studies. The findings revealed wide variations in dosimetric values and scan lengths among scanners, emphasizing the need for standardization and optimization. Incorporation of advanced technologies like Iterative Reconstruction (IR) showcased potential for further dose reduction, yet challenges in uniform implementation persist. The study underscores the importance of ongoing optimisation efforts, particularly in the context of increased CT utilization and evolving technology. The revised DRLs have been officially adopted in Greece, emphasizing the commitment to safe and effective CT practices.

Establishment and utilisation of national diagnostic reference level for adult computed tomography examinations in Ghana.

The International Atomic Energy Agency, as part of the new regional project (RAF/9/059), recommend the establishment of diagnostic reference levels (DRLs) in Africa. In response to this recommendation, this project was designed to establish and utilise national DRLs of routine computed tomography (CT) examinations. These were done by estimating CT dose index and dose length product (DLP) from a minimum of 20 patient dose report of the most frequently used procedures using 75th percentile distribution of the median values. In all, 22 centres that formed 54% of all CT equipment in the country took part in this study. Additionally, a total of 2156 adult patients dose report were randomly selected, with a percentage distribution of 60, 12, 21 and 7% for head, chest, abdomen-pelvis and lumber spine, respectively. The established DRL for volume CT dose index were 60.0, 15.7, 20.5 and 23.8mGy for head, chest, abdomen-pelvis and lumber spine, respectively. While the established DRL for DLP were 962.9, 1102.8, 1393.5 and 824.6mGy-cm for head, chest, abdomen-pelvis, and lumber spine, respectively. These preliminary results were comparable with data from 16 other African countries, European Commission and the International Commission on Radiological Protection. Hence, this study would serve as a baseline for the establishment of a more generalised regional and national adult DRLs for Africa and other developing countries.

National and local diagnostic reference levels for adult 18F-FDG and CT in Jordanian PET/CT: findings and implications in practice

This study aims to report the findings of Jordanian national diagnostic reference level (NDRL) survey for fluorodeoxyglucose (18F-FDG) and local diagnostic reference level (LDRL) of computed tomography (CT) used for attenuation correction and anatomical localisation (AC-AL); and AC and diagnostic CT (AC-DX) within the context of whole-body WB and half-body HB adult oncology PET/CT scanning. Two-structured questionnaires were prepared to gather the necessary information: dosimetry data, patient demographics, equipment specification, and acquisition protocols for identified 18F-FDG PET/CT procedures. The NDRL and achievable dose were reported based on the 75th and 50th percentiles for 18F-FDG administered activity (AA), respectively. The LDRL was reported based on the 50th percentile for (CTDIvol) and (DLP). Data from 562 patients from four Jordanian PET/CT centres were collected. The survey revealed that Jordanian NDRL for AA (303 MBq) was within the acceptable range compared to the published-peer NDRL data (240–590 MBq). However, the 18F-FDG AA varied across the participated PET/CT centres. The reported LDRL CTDIvol and DLP of CT used for (AC-AL) was 4.3 mGy and 459.3 mGy.cm for HB CT scan range, and 4.1 mGy and 659.9 mGy.cm for WB CT scans. The reported LDRL for CTDIvol and DLP for HB CT was higher when compared with the United Kingdom (3.2 mGy and 310 mGy.cm). Concurrently, in the context of WB CT, the reported values (i.e. CTDIvol and DLP) were also higher than both Kuwait (3.6 mGy and 659 mGy.cm) and Slovenia (3.6 mGy and 676 mGy.cm). The reported HB CT(AC-DX) was higher than Nordic, New Zealand and Swiss NDRLs and for WB (AC-DX) CT it was higher than Swiss NDRLs. This study reported the first Jordanian NDRL for 18F-FDG and LDRL for HB and WB CT associated with 18F-FDG PET/CT scans. This data is useful for Jordanian PET/CT centres to compare their LDRL to the suggested DRLs and utilise it in the process of optimising CT radiation doses.

Establishment of Diagnostic Reference Levels in Portuguese Interventional Radiology departments

PurposeTo establish Portuguese Diagnostic Reference Levels (DRLs), for six body fluoroscopy guided interventional procedures (FGIP). MethodA retrospective study was conducted in five interventional departments most representative of Interventional Radiology (IR) practice. Dose values, in terms of air kerma area product (PKA in Gy.cm2), air kerma at the patient entrance reference point (Ka,r in mGy), and exposure parameters (fluoroscopy time (FT) and number of cine runs) were collected. Examinations were selected per procedure (at least 20), according to the antero-posterior and lateral diameter mean value (±5 cm), measured on previous Computed Tomography (CT) examinations. ResultsData of 489 body FGIP show a large variation on dose values per procedure and per department. National DRLs in terms of PKA were 20.2 Gy.cm2 for Percutaneous transhepatic biliary drainage (PTBD), 98.2 Gy.cm2 for Bronchial artery embolisation (BAE), 247.7 Gy.cm2 for Transarterial chemoembolisation (TACE), 331.6 Gy.cm2 for Inferior epigastric arteries embolisation (IEAE), 312.0 Gy.cm2 for Transjugular intrahepatic portosystemic shunt (TIPS) and 19.3 Gy.cm2 for Endovascular treatment of femoral popliteal arteries (ETFPA). ConclusionsThis is the first study reporting Interventional Radiology DRLs in Portugal and we propose preliminary national estimates for the six more common body FGIP. The results of this study will be presented and discussed with all Portuguese IR departments, to promote procedures optimisation.

Enhancing Nuclear Medicine Practice in Saudi Arabia: Advocating for Comprehensive Guidelines and Local Diagnostic Reference Levels.

Diagnostic reference levels(DRLs) were initially introducedbythe International Commission on Radiation Protection (ICRP). It refers to the measured quantity ofadministered activity (MBq) in nuclear medicine imaging studies and is a type of investigation level. DRL is recommended to prevent excessive radiation exposure to patients while maintaining adequate image quality. It should not be implemented as a dose constraint or dose limit.The Saudi Food and Drug Authority (SFDA) is the primary government body responsible for reporting national diagnostic reference levels (NDRLs) for diagnostic medical imaging technologies in Saudi Arabia. Only NDRLs for computed tomography, general X-ray, and mammography have been published and enforced locally.This study aims to establish local DRLs for nuclear medicine imaging procedures at King Abdulaziz University Hospital, Saudi Arabia, preparing for compliance proof once required by local authorities. Data were collected from all machines, and sixcommon protocols were studied, with datafrom 50 patientsof standard body size for each identified protocol. The study was conducted retrospectively, and the 50thpercentile was then calculated for each scan. Both protocols for renal scansadministered the lowest doses to patients (130 MBq and 148 MBq), respectively. The highest dose administered to patients was found to be in bone scans (1110 MBq). The study establishes local DRLs for nuclear medicine imaging in our institution. Median activity dosages in renal, thyroid, and parathyroid imaging were comparable to locally and internationally published DRLs. However, they are higher in cardiac and bone imaging comparedto local Saudi DRL and DRL in the European Union and the USA, likely due to the adopted protocols. These highlight the need for modifying the protocols to fulfill optimization efforts. These findings serve as a foundation for compliance with future regulatory requirements, ensuring patient safety and maintaining imaging quality in Saudi healthcare.

An Approach to Establishing Diagnostic Reference Levels in Interventional Pediatric Cardiology from Different Regions of Brazil.

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.

Establishment of local diagnostic reference levels for CT colonography at a tertiary hospital.

Diagnostic reference levels (DRLs) are an important metric in identifying abnormally high radiation doses in diagnostic examinations. National DRLs for CT colonography do not currently exist in South Africa, but there are efforts to collect data for a national DRL project. This study investigated radiation doses for CT colonography in adult patients at a large tertiary hospital in South Africa with the aim of setting local DRLs. Patient data from two CT scanners (Philips Ingenuity and Siemens Somatom go.Top) in the period March 2020 - March 2023 were obtained from the hospital's picture archiving and communication system (PACS) (n = 115). Analysis involved determining the median computed tomography dose index-volume (CTDIvol) and dose-length product (DLP) values. The findings were compared with DRLs established internationally. Ingenuity median CTDIvol was 20 mGy and DLP was 2169 mGy*cm; Somatom median CTDIvol was 6 mGy and DLP was 557 mGy*cm. Ingenuity exceeded the United Kingdom's (UK) recommended DRLs by 82% and 214%, respectively. Somatom median CTDIvol and DLP were 45% and 19% lower than UK NDRLs. Somatom's tin filter and other dose reduction features provided significant dose reduction. These data were used to set DRLs for CT colonography at the hospital; CTDIvol: 6 mGy and DLP: 557 mGy*cm. In addition to informing radiation protection practices at the level of the institution, the established local DRLs contribute towards implementing regional and national DRLs.

National survey to update the diagnostic reference levels in interventional radiology procedures in Italy: working methodology.

Interventional Radiology (IR) deals with the diagnosis and treatment of various diseases through medically guided imaging. It provides unquestionable benefits to patients, but requires, in many cases, the use of high doses of ionizing radiation with a high impact on radiation risks to patients and to overall dose to the population. The International Commission on Radiological Protection introduced Diagnostic reference levels (DRLs) as an effective tool to facilitate dose verification and optimize protection for patients undergoing radiological procedures. In addition, EURATOM Council Directive 2013/59 and its Italian transposition (Legislative Decree 101/2020) have reiterated that DRLs must be established for many common radiological diagnostic procedures to compare the radiation dose delivered for the same diagnostic examination. Within this framework, Istituto Superiore di Sanità-Italian National Institute of Health (ISS)-, in collaboration with relevant Italian Scientific Societies, has provided documents on DRLs in radiological practices such as diagnostic and IR and diagnostic nuclear medicine. These reference documents enable National Hospitals to comply national regulation. The implementation of DRLs in IR is a difficult task because of the wide distribution of doses to patients even within the same procedure. Some studies have revealed that the amount of radiation in IR procedures is influenced more by the complexity of the procedure than by the weight of the patient, so complexity should be included in the definition of DRLs. For this reason, ISS promoted a survey among a sample of Italian Centers update national DRL in IR procedures with related complexity factors than can be useful for other radiological centers and to standardize the DRLs values. In the present paper the procedural methodology developed by ISS and used for the survey will be illustrated.

Evaluation of radiation dose and establishment of local DRLs for adult during abdominopelvic CT scan imaging for university hospital centers, Morocco

Objective: In this study, we have planned to establish the local Diagnostic Reference Levels (DRLs) for the five University Hospital Centers in Morocco and to propose a national DRL for abdominopelvic CT examinations for adult patients. Materials and methods: Data were collected using a specially designed form, which included patient demographics, exposure parameters and dosimetric indicators such as dose-length product (DLP) and CT volume dose index (CTDIvol). The establishment of local and national DRL in terms of CTDIvol and DLP was carried out in accordance with the methodology described in Report 135 of the International Commission on Radiological Protection (ICRP). The effective dose was assessed using the DLP and the dose conversion factor appropriate for this location. Results: A total of 300 patients undergoing abdominopelvic examinations at the five Moroccan university hospitals were collected for this study. Patients' mean age, weight and BMI were (50.97 ± 15.05) years (67.94 ± 11.41) Kg and (25.71 ± 3.03) Kg/m2 respectively. The local DRL, in terms of DLP were 551.56, 2293.33, 709.02, 843.52 and 1059.62 mGy-cm and in terms of CTDIvol were 11,05, 46,40, 13,14, 12,01, 9,88 mGy respectively for UHC-1, UHC-2, UHC-3, UHC-4 and UHC-5 hospitals. The proposed National DRL, defined as a single value for the 75th percentile on the aggregation of data from the five centers, for abdominopelvic scan CT was 773.20 mGy.cm and 12.05 mGy for DLP and CTDIvol, respectively. Conclusion: The Moroccan DRL was comparable to those of other countries, ranking 10th among 21 countries. However, we are still seeking to reduce and optimize radiation dose while maintaining good image quality for reliable diagnosis, and this can be achieved by enhancing radiographers' and radiologists' knowledge of radiation protection, protocol justification, and optimization through rigorous hospital radiation audits at national level.

Establishment of local diagnostic reference levels for breast cancer CT protocols in radiotherapy in a single Moroccan center

The objective of this study was to establish local diagnostic reference levels (LDRLs) for breast cancer computed tomography imaging in radiotherapy (CT-RT) at a single hospital in Morocco. Data were collected from 106 adult breast cancer patients aged between 33 and 78 yr during five months. Data were obtained using a Hitachi Supria 16-slice CT simulator at a regional oncology center in Morocco. CT-RT images are intended for 3D conformal radiotherapy treatment planning. Dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were evaluated by determining the 75th percentile as diagnostic reference levels for CT-RT breast cancer. LDRLs for CT-RT breast cancer have been determined in terms of DLP and CTDIvol, and they were 330.4 mGy.cm and 6.8 mGy, respectively. The DRLs were compared with other Europeans study. DRLs for this study were lower than those for the United Kingdom (UK), Croatia and Slovenia. The results of this study can be a reference for the establishment of local and national DRLs in Morocco and the optimization of CT-RT breast cancer procedures.

Radiological imaging protection: a study on imaging dose used while planning computed tomography for external radiotherapy in Japan.

Previous studies have primarily focused on quality of imaging in radiotherapy planning computed tomography (RTCT), with few investigations on imaging doses. To our knowledge, this is the first study aimed to investigate the imaging dose in RTCT to determine baseline data for establishing national diagnostic reference levels (DRLs) in Japanese institutions. A survey questionnaire was sent to domestic RT institutions between 10 October and 16 December 2021. The questionnaire items were volume computed tomography dose index (CTDIvol), dose-length product (DLP), and acquisition parameters, including use of auto exposure image control (AEC) or image-improving reconstruction option (IIRO) for brain stereotactic irradiation (brain STI), head and neck (HN) intensity-modulated radiotherapy (IMRT), lung stereotactic body radiotherapy (lung SBRT), breast-conserving radiotherapy (breast RT), and prostate IMRT protocols. Details on the use of motion-management techniques for lung SBRT were collected. Consequently, we collected 328 responses. The 75th percentiles of CTDIvol were 92, 33, 86, 23, and 32mGy and those of DLP were 2805, 1301, 2416, 930, and 1158mGy·cm for brain STI, HN IMRT, lung SBRT, breast RT, and prostate IMRT, respectively. CTDIvol and DLP values in institutions that used AEC or IIRO were lower than those without use for almost all sites. The 75th percentiles of DLP in each treatment technique for lung SBRT were 2541, 2034, 2336, and 2730mGy·cm for free breathing, breath holding, gating technique, and real-time tumor tracking technique, respectively. Our data will help in establishing DRLs for RTCT protocols, thus reducing imaging doses in Japan.

Establishment of local diagnostic reference levels for abdomen and chest radiographies in the region of Algarve, Portugal

PurposeTo assess doses variabilities in the same abdomen and chest RX exams for adults, to check the need for dose harmonization. To calculate Diagnostic Reference Levels (DRL), mandatory in the European Union, for the Algarve district in Portugal. Our results can be a valuable reference for the Portuguese official determination of DRLs, still in progress. MethodWe considered 4,936 abdomen and 41,320 chest radiographs of adults, covering 7 health centres and 35 radiographers in Algarve. Entrance skin dose (ESD) was calculated for each radiograph and the corresponding uncertainty estimated. Mean doses per centre and per technician, and their uncertainties, were calculated to access dose variabilities. DRLs, set at the 3rd quartile of the total ESD distribution, were determined for a standard patient and for intervals of body mass index (BMI) to study their correlation with patient anatomical variations. Standard quartile errors were estimated. ResultsOur results suggest significant dispersion in applied ESDs among different centres and radiographers. Estimates of DRLs also show small fluctuations across years and an important dependence on BMI intervals. For a standard patient, they are 8.7 ± 0.1 (abdomen) and 0.44 ± 0.01 (chest), while the European DRLs are, respectively, 5.1 and 0.2 (all in mGy). ConclusionsResults suggest that there is room for dose optimization and harmonization with European DRLs, urging a national dose survey and the establishment of official national DRLs. Official DRLs in intervals of BMI would be quite beneficial, to avoid unnecessary dose exposures.