International Diagnostic Reference Levels Research Articles

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.

Evaluation of X-ray doses in paediatrics multislice computed tomography

The present paper aims to examine the doses delivered to children at the paediatric Computer Tomography (CT) unit in the radiology service of the Mother and Child Hospital (MCH) in the Mohammed VI University Hospital Centre (Med VI UHC) of Marrakech, Morocco, and to compare our values with the dosimetric data of the published literature. This investigation included 440 CT examinations of the head, chest, and abdomen-pelvis in paediatric patients whose ages ranged from 1 to 5 yr (AG1y­5y), 5 to 10 yr (AG5y­10y), and 10 to 15 yr (AG10y­15y). We estimated the 75th percentile values of the Volume Computed Tomography Dose Index CTDIvol (mGy) and the Dose-Length-Product DLP (mGy.cm). The obtained results showed that the calculated 75th percentile of DLP for head CT are less than the National Diagnostic Reference Levels (DRLs) observed in Japan, Belgium, Germany, French, United Kingdom, United State, and China. However, the proposed DRLs for the abdomen-pelvis, and chest CT are significantly higher compared with international DRLs.

Assessment of diagnostic reference levels for paediatric cardiac computed tomography in accordance with European guidelines

Recently, paediatric cardiac computed tomography (CCT) has caused concerns that diagnostic image quality and dose reduction may require further improvement. Consequently, this study aimed to establish institutional (local) diagnostic reference levels (LDRLs) for CCT for paediatric patients, and assess the impact of tube voltage on proposed DRLs in terms of the volume computed tomography index (CTDIvol) and dose length product (DLP). In addition, effective doses (EDs) of exposure were estimated. A population of 453 infants, whose mass and age were less than 12 kg and 2 years, respectively, were considered from January 2018 to August 2021. Based on previous studies, this number of patients was considered to be sufficient for establishing LDRLs. A group of 245 patients underwent CCT examinations at 70 kVp tube voltage with an average scan range of 23.4 cm. Another set of 208 patients underwent CCT examinations at 100 kVp tube voltage with an average scan range of 15.8 cm. The observed CTDIvol and DLP values were 2.8 mGy and 54.8 mGy.cm, respectively. The mean effective dose (ED) was 1.2 mSv. It is concluded that provisional establishment and use of DRLs for cardiac computed tomography in children are crucial, and further research is needed to develop regional and international DRLs.

Establishment of institutional diagnostic reference level for Computed Tomography dose on 160 slicer Computed Tomography scan at Lady Reading Hospital Peshawar.

To set institutional diagnostic reference level for computed tomography of multiple anatomical regions using dose length product as dosimeter parameter and to compare results with international diagnostic reference level. The retrospective study was conducted at the Radiology Unit of Lady Reading Hospital, Peshawar, Pakistan, and comprised dose data of patients who underwent computed tomography from June 1 to August 31, 2018. The mean, 25th, 50th and 75th percentile of dose distribution of common computed tomography examinations was calculated and compared with other established diagnostic reference levels. Data was analysed using SPSS 20. Of the 1001 scans, 143(14.2%) related to brain, 275(27.5%) abdomen-pelvis, 133(13.3%) kidney-ureter-bladder, 186(18.58%) thorax, 85(8.49%) triphasic, 126(12.58%) musculoskeletal, and 53(5.29%) cardiac. Institutional diagnostic reference levels for the computed tomography unit was established as 50th percentile of dose length product for different regions brain 339, abdomen-pelvis 298, thorax 165, kidney-ureter-bladder 302, triphasic 633, musculoskeletal 366 and cardiac 403. Both 50th and 75th percentile values of dose length product for each individual body region was lower than international Diagnostic reference levels. The diagnostic reference level will be used in routine computed tomography practice at the institution, and will act as the baseline for developing the national diagnostic reference levels.

Systematic Review on Diagnostic Reference Levels for Computed Tomography Examinations in Radiation Therapy Planning

Background: In August 2017, the European Commission awarded the "European Study on Clinical Diagnostic Reference Levels (DRL) for X-ray Medical Imaging" project to the European Society of Radiology to provide up-to-date Diagnostic Reference Levels based on clinical indications. This work aimed to conduct an extensive literature review by analyzing the most recent studies published and the data provided by the National Competent Authorities to understand the current situation regarding Diagnostic Reference Levels based on clinical indications for Radiation Therapy Computed Tomography. Objective: To review the literature on established DRLs and methodologies for establishing Diagnostic reference levels in radiation therapy planning computed tomography (RTCT). Methods: Eligibility criteria: A cohort study (observational design) reporting DRLs in adult patients undergoing computed tomography (CT) for radiation therapy for the region head and neck or pelvis were included. The comprehensive literature searches for the relevant studies published between 2000 and 2021 were performed using PubMed, Scopus, CINHAL, Web of Science, and ProQuest. Results: Three hundred fifty-six articles were identified through an extensive literature search. Sixty-eight duplicate reports were removed. The title and abstract of 288 studies were assessed and excluded if they did not meet the inclusion criteria. Sixteen of 288 articles were selected for full-text screening (studies conducted between 2000 and 2021). Five articles were included in the review after the full-text screening. Conclusions: A globally approved standard protocol that includes scanning techniques, dose measurement method, and DRL percentile needs to be established to make a valuable and accurate comparison with international DRLs.

An audit of patient radiation doses in interventional radiology at a South African hospital.

Interventional radiology (IR) is becoming more relevant in patient care and is associated with increased patient radiation exposure and radiation-induced adverse effects. Diagnostic reference levels (DRLs) are crucial for radiation control. There is a paucity of published DRLs for IR in South Africa and sub-Saharan Africa. This study aimed to determine local DRLs for fluoroscopically-guided IR procedures and compare the achieved DRLs with published local and international DRLs. Retrospective, descriptive, single-centre study. Kerma air product (KAP), reference point air kerma (Ka,r) and fluoroscopy time (FT) were collected for patients (12 years and older) who underwent IR procedures at a university hospital from 01 January 2019 to 31 December 2019. The 75th percentile of the distribution of each dose parameter (KAP, Ka,r and FT) per procedure was calculated and taken as the local diagnostic reference levels (LDRL). The established LDRLs were compared to published DRLs. A total of 564 cases were evaluated. The 13 most frequent procedures (with 15 or more cases) represented 86.1% (487/564). Percutaneous transhepatic biliary drainage was the most common procedure (n = 146, 25.9%). Diagnostic cerebral angiogram DRLs exceeded the published DRL data ranges for all parameters (DRL 209.3), and interventional cerebral angiogram exceeded published ranges (DRL 275). Uterine artery embolisation (UAE) exceeded these ranges for KAP and Ka,r. (KAP-954.9 Gy/cm2, Ka,r-2640.8 mGy). The LDRLs for diagnostic cerebral angiogram, interventional cerebral angiogram and UAE exceeded published international DRL ranges. These procedures require radiation optimisation as recommended by the International Commission on Radiological Protection (ICRP). In addition to informing radiation protection practices at the level of the institution, the established LDRLs contribute towards Regional and National DRLs.

Estimation of radiation dose associated with bone SPECT/CT and establishing local diagnostic reference levels using size-specific dose estimate

Single-photon emission computed tomography (SPECT) and X-ray computed tomography (CT) is used to diagnose and monitor the skeletal system. However, due to the combination of injected activity and CT radiation dose, its usage is linked to an increase in patient radiation exposure. This study aims to estimate the radiation dose received by patients while undergoing bone SPECT/CT and to establish its local diagnostic reference level (LDRL). In this retrospective study, data from 30 patients who had undergone bone scans were obtained from two hospital imaging devices. The effective doses (E) of the radiopharmaceutical agent and CT components were calculated. Furthermore, the patients' anteroposterior thickness at the midline and lateral widths were measured from their CT images to determine the size-specific dose estimate (SSDE). The mean age of the patients was 53.53 ± 16 years. They were administered an injection activity of 740 MBq of 99mTc-Methyl diphosphonate for SPECT, yielding an E of 2.78 mSv. The mean CTDIvol, DLP, SSDE, and E values for the CT component were 8.76 ± 3.25 mGy, 350 ± 138 mGy cm, 13 ± 4 mGy, and 4.90 ± 1.94 mSv, respectively. Patients received a combined dose of 7.68 mSv from the radiopharmaceuticals and CT. The proposed LDRL for SPECT was comparable to international DRLs, but the CT LDRL was slightly higher. An SSDE-based LDRL is proposed. Moreover, the overall patient dose can be reduced even further by optimizing the injected activity and CT imaging factors.

Substantiation of a new approach to the criteria for assessing the radiation dose of patients during computed tomography

BACKGROUND: In accordance with the requirements of the IAEA basic safety standards and the International Commission on Radiation Protection, comparing the radiation dose for patients undergoing computed tomography (CT) in diagnostic and treatment clinics with national or international DRLs is important for controlling medical radiation doses. The search for ways to improve DRLs calculations determines the relevance of such studies.&#x0D; AIM: To analyze the dependence of effective doses (EDs) in CT of different body parts on patients weight and to calculate the standard ED for the patient (70 and 80 kg).&#x0D; MATERIALS AND METHODS: CT acquisition protocols in 209 patients were single phase (SP) CT, while 114 patients underwent multi-phase (MP) CT. ED was calculated according to the normalized coefficients for each body area. The values of standard ED was calculated by data approximation using linear function of ED relatively body weight for each type CT scanner and body area scanned.&#x0D; RESULTS: The increase in ED following a CT examination was proportional to the body weight of patients. For SP and MP CT scans, the standard EDs were calculated according to all body areas. The mean ED, median ED, and DRLs (mSv) in these groups was slightly higher than standard ED (mSv) if the criterion was 70 kg and were close to standard ED if the criterion was 80 kg. These values give a basis for improving the guidelines concerning the recommended limits of radiation doses for CT in individual patients according to indications and body parts studied.&#x0D; CONCLUSIONS: In the study, a methodology for assessing and comparing the dose of CT-radiation at two hospitals in the two CT scanners, considering weight of a standard patient, is described. Our results show that the calculation and analysis of the standard ED of CT-examining areas of the body instead of mean ED and median ED help to compare the radiation exposure in different medical facilities more properly. Given the recent sharp increase in the number of CT studies, not exceeding the standard ED for patients with CT will reduce the long-term consequences in the form of oncological pathology among the population.

A Comparison of the Mean CTDIvol and DLP Values for Adult Abdominal CT Examination for MTRH, Eldoret Hospital, St. Luke’s Hospital and Mediheal Hospital: A Retrospective Study

Background: Advances in Computed Tomography (CT) have facilitated widespread use of medical imaging while increasing patient lifetime exposure to ionizing radiation. In Kenya we use the international DRLs as our point of reference and so far, no regional protocols for abdominal CT scan have been adopted. This study endeavors to form a basis for dose reference levels protocols for abdominal CT scan in Uasin Gishu County. Objective: To compare the mean CTDIvol and DLP values for adult abdominal CT examination for MTRH, Eldoret Hospital, St. Luke’s Hospital and Mediheal Hospital. Methods: This was a retrospective review of CT scans of 700 adult patients conducted in Uasin Gishu healthcare system at MTRH, Eldoret Hospital, Mediheal Hospital and St. Luke’s Hospital in a period of 1 year in the year 2021 using systematic and consecutive sampling. The Volumetric CT-dose index (CTDIvol) and dose length product (DLP) length from CT abdominal scans for the adults were collected from the various CT scans dose tracking software’s. Results: The mean age of patients who underwent CT abdominal scans was 52 years with majority being females at 53 %. The mean CTDIvol was 81. (SD=22.2) and the mean DLP values was 1699.1 (SD=1053.1). Comparison by scan model demonstrated the median for the Total DLP and for the CTDIvol significantly differed by the model with the median for the Neusoft model being highest at 2538 mGy.cm and 10.3mGy respectively while those for the Siemens were the lowest for the two markers at 1318.5 mGy.cm for the DLP and 5.39mGy respectively. These findings were statistically significant with a p value of &lt; 0.001. Comparison by the type of facility showed that the median DLP and CTDIvol values were significantly higher in the public facilities at 1668.8mGy.cm and 6.3mGy respectively when compared to private facilities at 1282.4mGy.cm and 5.9mGy with a p value of &lt;0.001. The Local Dose reference level (LDRL) was set as the median value for CTDIVOL and DLP at 6.1mGy and 1465 mGy.cm respectively. Conclusions: The LDRLs for the patients undergoing abdominal CT examination in Uasin Gishu healthcare system were markedly lower than the regional and the international values for the same abdominal CT examination.

Statistical study for Radiation Dose Reference levels of Adult Computer Tomography Abdominal studies in Eldoret Kenya

Objective: To establish dose reference levels for the adult abdominal CT scan modality at MTRH, Eldoret Hospital, St. Luke’s Hospital and Medi heal Hospital in reference to the international DRLs. Methods: A retrospective study, reviewed CT scans of 700 adult patients conducted in the 4 health institutions from Uasin Gishu healthcare system in a period of 1 year in the year 2021 using systematic and consecutive sampling. The Volumetric CT-dose index (CTDIvol) and dose length product (DLP) length from the various adult CT abdominal scans were obtained. Results: The mean CTDIvol was 8.1 (22.2) and the mean DLP values was 1699.1 (1053.1). Comparison by scan model it was observed that the median for the Total DLP and for the CTDIvol significantly differed by the model with the median for the Neusoft model being highest at 2538 mGy.cm and 10.3mGy respectively while those for the Siemens were the lowest for the two markers at 1318.5 mGy.cm for the DLP and 5.39mGy respectively. These findings were statistically significant with a p value of &lt; 0.001. Comparison by the type of facility it was observed that the median DLP and CTDIvol values were significantly higher in the public facilities at 1668.8mGy.cm and 6.3mGy respectively when compared to private facilities at 1282.4mGy.cm and 5.9mGy with a p value of &lt;0.001.The Local Dose reference level (LDRL) was set as the median value for CTDIVOL and DLP at 6.1mGy respectively. Conclusions: The LDRLs for the adult patients undergoing abdominal CT examination in Uasin Gishu healthcare system were markedly lower than the regional and the international values for the same abdominal CT examination.

Paediatric effective radiation doses during brain computed tomography angiography procedure

In comparison to adults and paediatric are more sensitive to ionizing radiation exposure. Computed tomography (CT) is now the dominant source of medical radiologic tests for patients, accounting for more than 70% of total doses to the general public. Paediatric CT brain scans (with and without contrast) are routinely performed for a variety of clinical reasons. As a result, this parameter must be calculated in order to determine relative radiation risk. The goal of this study is to assess the radiation risk to children during CT brain diagnostic procedures. Three hundred fifty three child patients' radiation risk doses were assessed over the course of a year. The mean and ranged of the children's radiation doses were 40.6 ± 8.8 (27.8–45.8) CTDIvol (mGy) and 850 ± 230 (568.1–1126.4) DLP (mGy.cm) for the brain with contrast medium. For CT brain without contrast, the patients' doses were 40.9 ± 9.4 (14.27–64.07) CTDIvol (mGy), and 866.1 ± 289.3 (203.6–2484.9) DLP (mGy.cm). The characteristics related to the radiation dose were retrieved from the scan protocol generated by the CT system by the participating physicians after each procedure. Furthermore, optimizing the CT acquisition parameter is critical for increasing the benefit while lowering the procedure's radiogenic risk. The patients' radiation dose is comparable with the most previously published studies and international diagnostic reference levels (DRLs). Radiation dose optimization is recommended due to high sensitivity of the paediatric patients to ionizing radiation.

Radiation metrics for vascular and interventional radiology procedures in a tertiary care institution: A retrospective cohort study over 5-years.

To evaluate the radiation metrics from frequently carried out vascular and interventional radiology (VIR) procedures at a tertiary care institution and compare them to international diagnostic reference levels (DRLs). A retrospective study of the radiation metrics of VIR-procedures carried out from January 2015 to December 2019. The collected data included age, gender, height and weight, reference point air kerma (mGy), dose area product (DAP; Gy.cm2), and fluoroscopy time (min.) The body mass index (BMI) and peak skin dose were calculated. The study cohort included 8942 adult patients (54.4% male, 45.6% female) with a mean age of 56.96 years and mean BMI of 26.86. Transjugular intrahepatic portosystemic shunt (TIPS) creation recorded the highest mean fluoroscopy time of 69.41 min., followed by central venous recanalization 39.67min. TIPS creation had the highest mean DAP (1161.16Gy.cm2), followed by trans arterial chemoembolisation (TACE) (500.63Gy.cm2). TIPS creation was associated with the highest peak skin dose (2766.81mGy), followed by TACE (1588.29mGy). Compared to other studies, TIPS creation and TACE are associated with significantly higher DAP. Majority of VIR-procedures demonstrate no significant institutional variations in dosimetry compared to other studies. Using these studied values as reference levels may help identifying procedures that need quality control to minimize unnecessary exposures.

Establishment of institutional diagnostic reference levels for 6 adult computed tomography examinations: Results from preliminary data collection

Computed tomography (CT) is the leading source of the cumulative effective doses to the general populace from medicinal and artificial sources. With the increased use of CT examinations comes the concern regarding the health effects of unnecessary radiation exposure and the need to optimize the doses that patients receive. The current study evaluates the patients' doses during specific CT procedures and establishes institutional diagnostic reference levels (DRLs) for the frequent CT scans performed. 8156 CT scan examinations were performed during three years from 2015 to 2018 using a single CT scan machine at our institution. Data from the six most common examinations were analyzed. The volume CT dose index (CTDIvol (mGy)) and dose length product (DLP) distribution's median and 75th percentile values were computed. The results were descriptively compared with DRLs from different countries and regions. The six most common examinations constituted 5815 studies. We established our DRLs as the median value of CTDIvol (mGy)| and DLP (mGy × cm) as follows: CT of the brain: 35.0 mGy and 839 mGy× cm, respectively; chest with contrast: 4 mGy and 148 mGy-cm, respectively; chest without contrast: 5 mGy and 190 mGy-cm, respectively; abdomen and pelvis with contrast: 8 mGy and 636 mGy-cm, respectively; abdomen and pelvis without contrast 8 mGy and 568 mGy-cm, in that order; abdomen, pelvis, and kidneys: 11 mGy and 458 mGy× cm, respectively. Our values for brain and chest CTs were lower than the international DRLs, while those for abdominal imaging were higher. The established DRLs offer an opportunity for us to optimize the dose delivered to patients and compare them to the national benchmarks when they are issued. The study revealed that CT dose showed wide discrepancies for the same procedures at the department levels suggesting that the practice was neither optimized nor harmonized. Therefore, DRL should be reassessed after the operators' training and awareness to reduce the patients' dose and related radiogenic risk to its minimal value.

2021 NATIONAL DIAGNOSTIC REFERENCE LEVELS FOR PAEDIATRIC COMPUTED TOMOGRAPHY IN EGYPT.

To establish national diagnostic reference levels (NDRLs) for most common paediatric computed tomography (CT) examinations in Egypt. This was a prospective study that included all dedicated paediatric imaging centers in Egypt. Data from 1680 individual paediatric patients undergoing CT scanning of the head, chest and abdomen-pelvis were collected. Computed tomography dose indices were recorded, data were analysed and compared with the internationally published paediatric DRLs in14 countries. The Egyptian NDRLs of the CTDIvol (mGy) for head, chest and abdomen-pelvis scans among four paediatric age groups were found to be (23, 27, 28, 32, 4, 5, 6, 8, 5, 6, 7, 9) mGy, respectively; and the corresponding NDRLs of the DLP (mGycm) for head, chest and abdomen-pelvis scans were found to be (345, 428, 499, 637, 67, 85, 145, 215, 97, 135, 240, 320) mGycm, respectively. There were variations in the radiation doses between CT centers and identical scanners indicating the need for dose optimization. The NDRLs of the CTDIvol (mGy) and the DLP (mGycm) values were similar to or lower than international DRLs. This study summarizes the results of the first Egyptian Computed Tomography survey that provides national diagnostic reference levels for paediatric patients in Egypt. Despite the reasonable NDRLs values, the study depicted certain pros and cons concerning CT practice, and identified some problems that hinder the process of optimization as well as justification in children.

ESTABLISHMENT OF REGIONAL DIAGNOSTIC REFERENCE LEVELS IN ADULT COMPUTED TOMOGRAPHY FOR FOUR AFRICAN COUNTRIES: A PRELIMINARY SURVEY.

This preliminary study aims towards the establishment of regional diagnostic reference levels (DRLs) for routine adult computed tomography (CT) examinations. The study was performed on 54 CT facilities from four African countries (Ghana, Kenya, Namibia and Senegal) and the results compared with international DRLs. Data were collected from facilities using a structured questionnaire provided by the International Atomic Energy Agency. Dose descriptors (volume computed tomography dose index [CTDIvol] and dose length product [DLP]) evaluations were performed on CT head and body phantoms for head, chest and abdomen CT examination protocols using standard methods. The estimated dose indices were compared with console-displayed dose values. Experienced radiologists accepted the diagnostic image quality of the images as per departmental imaging requirements. Median CTDIvol and DLP data from each facility were compiled to estimate the typical dose in each country. National DRLs were established based on the 75th percentile of median values, whereas the regional DRLs were based on the median of the national DRLs. Comparison of measured CTDIvol with console values of all facilities in all four countries was within 20% as recommended. The established CTDIvol DRLs for head CT, chest CT and abdomen CT were 60.9mGy, 15.2mGy and 15.7mGy, respectively. Similarly, that of DLP, DRLs were 1259mGy.cm, 544mGy.cm and 737mGy.cm, respectively for head CT, chest CT and abdomen CT. The established DRLs from this study were comparable to DRLs from other countries with some variations. This study would serve as baseline for establishment of a more generalized regional adult CT DRLs for Africa.

Establishment of Local Diagnostic Reference Levels in Conventional Radiography: A Pilot Study in Dakar, Senegal

Diagnostic Reference Levels (DRLs) are indicators that allow assessing the quality of equipment and procedures from the point of view of the doses delivered to patients and subsequently initiate corrective actions if necessary. The purpose of this study is to encourage health professionals to investigate patient radiation doses and to determine whether those doses comply with the principles of radiation protection in medical fields so as to improve practices by reducing patient exposure without reducing clinical effectiveness. To perform this work, we have investigated patient doses for different radiological examinations from six (6) medical centers in Dakar, including the following nine routine types: chest (PA), abdomen (AP), pelvis (AP), cervical spine (AP), lumbar spine (AP, Lat), hip (AP), thoracic spine (AP, Lat). Three types of data were collected, i.e., X-ray tube machine data, patient data and output measurements. The data were analyzed statistically and the median, minimum, maximum, and third quartile values were calculated and displayed throughout boxplots graphs for all exams and medical centers. The two sigma range (95% confidence interval) was also checked. Comparison of third quartiles of Entrance Surface Dose (ESD) and Dose Area Product (DAP) by type of examination with recommended international DRLs was performed. The third quartile of ESD for pelvis (AP) and thoracic spine (AP) was up to 16% and 38% higher, respectively than their corresponding DRLs in the European Commission Report RP 180 Part 2. For all exams, except thoracic spine (lat), the third quartiles of the dose area product were higher than the corresponding DRLs in the above report. The source of dose variability between medical centers was related to many parameters such as poor radiographic techniques, lack of modern X-ray machines and adequately documented radiation protection practices. The results show the need to develop protocols for dose measurement as well as to carry out quality assurance programs and dose optimization in Senegal.

Comparison of Radiation Dose in CT Examinations At PIMS with European Commission Reference Doses

OBJECTIVE - The purpose of this study was to assess the radiation dose levels from common computed tomography (CT) examinations performed in Radiology Department of Pakistan Institute of Medical Sciences (PIMS), and evaluate these according to diagnostic reference levels (DRLs) proposed by European Commission (EC) guidelines, and thus contributing towards the establishment of local and national DRLs. To the best of our knowledge, this is the first study of its kind to explore radiation doses from CT examinations in Pakistan.&#x0D; STUDY DESIGN - This was a quantitative study conducted at PIMS, Islamabad, spanning a duration of eight weeks. Scan parameters and dose profile data of 1506 adults undergoing examinations of head, neck, chest and abdomen-pelvis regions, comprising of single- and multi-phase, contrast-enhanced and unenhanced studies. Dose indicators utilized by EC guidelines for DRLs include volume CT dose index (CTDIvol) and Dose Length Product (DLP) for single slice and complete examination radiation doses, respectively.&#x0D; METHOD - Values of CTDIvol, DLP and scan lengths were extracted from the CT operators console. Other control variables included gender, contrast enhancement and phasicity of study. IBM SPSS package was used to obtain descriptive statistics such as mean and quartiles.&#x0D; RESULTS - DRLs calculated as 75th percentile of CTDIvol, DLP for various anatomical regions are by and far comparable to European DRLs.&#x0D; CONCLUSION – This study describes institutional diagnostic reference levels for common CT exams in Islamabad and provides benchmark values for future reference. Our DRL values are mostly comparable to European and international DRLs. Similar, albeit large scale, surveys are recommended for establishment of local and national DRLs, eventually contributing towards development of regional DRLs.&#x0D; KEYWORDS: CTDIvol, DLP, Diagnostic Reference Levels, Computed Tomography, Radiation Monitoring, Scan length

ESTABLISHING LOCAL DIAGNOSTIC REFERENCE LEVELS FOR ROUTINE COMPUTED TOMOGRAPHY EXAMINATIONS IN JIMMA UNIVERSITY MEDICAL CENTER SOUTH WEST ETHIOPIA.

The main purpose of this study was to determine local diagnostic reference level (LDRL) for Routine Computed Tomography (CT) examination in, Jimma University Medical Center (JUMC) South West Ethiopia. Retrospective study was conducted to determine LDRL for routine CT examination in JUMC. We have considered CTDIvol and DLP as dosimetric quantity based on the recommended guidelines to determine LDRLs by different international legal Authorities. The 75th percentile values of the calculated CTDIvol and DLP were proposed as LDRL. LDRL was obtained as CTDIvol, 42.97mGy, 7.76mGy, 14.32mGy, and 10.86mGy for routine brain CT, routine chest CT, routine thoraco-lumbar CT and routine abdomen CT examination respectively. Similarly the determined LDRL from DLP was 1364.15mGycm, 368.96mGycm, 853.18mGycm, and 1568.96mGycm for brain, chest, thoraco-lumbar and abdomen examination respectively. The LDRL obtained for DLP was higher compared with international DRLs; it can be reduced by coordinating effort between radiologists, technologists and medical physicist.

Towards the Establishment of Diagnostic Reference Levels in Saudi Arabia: Review and Opinion

THIS STUDY aims at providing an overview and evaluation of the current situation of the national Diagnostic Reference Levels (DRLs) in Saudi Arabia. Studies published in Pubmed and Google-Scholar, since the DRLs were proposed, are reviewed and general considerations are highlighted, by reviewing some established international DRLs, regarding x-rays and nuclear medicine modalities. The importance of national DRLs (Saudi DRLs) is introduced and discussed. An overview of some studies on Saudi DRLs regarding selected procedures is presented and the validity of radiation dosimetry studies for establishing Saudi DRLs is discussed. The establishment of DRLs for pediatric patient procedures is introduced, discussed and emphasized. An enormous amount of work is required to establish the Saudi DRLs for different procedures, as more than 90% of the work has not been accomplished. Collaboration between researchers is necessary to allow comparisons of DRLs results and to validate the establishment of Saudi DRLs. Furthermore, DRLs for pediatric patient procedures should take priority.

Evaluation of age-based radiation dose in paediatric patients received from head CT examination at a tertiary hospital, Nigeria

Paediatric computed tomography (CT) imaging though requested less than adult CT but has shown remarkable growth with raising concerns of increased radiation risk to the paediatric population. This study aims to evaluate age-based radiation dose from paediatric head CT scans at a single centre in Nigeria. This study evaluated 233 paediatric aged 0–15 years and were classified into four age groups; Group 1 (≤1 year), Group 2 (2–5 years), Group 3 (6–10 years) and Group 4 (11–15 years). Patient dose and related scanning protocol data were retrospectively retrieved from the CT scanner. The local dose values were calculated as 25th and 75th percentiles of the distribution of the volume CT dose index (CTDIvol), dose length product (DLP) and effective dose per age-group. These values were compared with the recommended international diagnostic reference levels (DRLs). The estimated dose values were within limits for the youngest age group (≤1 year old) but showed a clear trend towards higher doses for other age groups as compared with DRLs. The relative difference for CTDIvol and DLP were ranged between 0‒45% and 8–64%, respectively. The largest difference in DRLs was seen in Group 3 and 4. The dose values were increased with the increasing age; Group 1 received the lowest doses (20 mGy, 345 mGy.cm, and 3.2 mSv) and Group 4 received the highest doses (61 mGy, 1497 mGy.cm, and 4.4 mSv). The local doses were substantially higher than the international DRLs values except for age group ≤1 year, demonstrating a necessity for dose optimization and modification of current acquisition technique towards the reduction of radiation dose among paediatric population.