Clinical diagnostic reference levels in neuroradiology based on clinical indication.

This study focuses on patient radiation exposure in interventional neuroradiology (INR) procedures, a field that has advanced significantly since its inception in the 1980s. INR employs minimally invasive techniques to treat complex cerebrovascular diseases in the head, neck, and spine. The study establishes diagnostic reference levels (DRLs) for three clinical indications (CIs): stroke (S), brain aneurysms (ANs), and brain arteriovenous malformation (AVM). Data from 209 adult patients were analyzed, and DRLs were determined in terms of various dosimetric and technical quantities. For stroke, the established DRLs median values were found to be 78 Gy cm2, 378 mGy, 118 mGy, 12 min, 442 images, and 15 runs. Similarly, DRLs for brain AN are 85 Gy cm2, 611 mGy, 95.5 mGy, 19.5, 717 images, and 26 runs. For brain AVM, the DRL's are 180 Gy cm2, 1144 mGy, 537 mGy, 36 min, 1375 images, and 31 runs. Notably, this study is unique in reporting DRLs for specific CIs within INR procedures, providing valuable insights for optimizing patient safety and radiation exposure management.

Strengthening education and training programmes for medical physics in Asia and the Pacific: the IAEA non-agreement technical cooperation (TC) regional RAS6088 project.

This article documents the work conducted in implementing the IAEA non-agreement TC regional RAS6088 project "Strengthening Education and Training Programmes for Medical Physics". Necessary information on the project was collected from the project counterparts via emails for a period of one month, starting from 21st September 2023, and verified at the Final Regional Coordination Meeting in Bangkok, Thailand from 30th October 2023 to 3rd November 2023. Sixty-three participants were trained in 5 Regional Training Courses (RTCs), with 48%, 32% and 20% in radiation therapy, diagnostic radiology, and nuclear medicine, respectively. One RTC was successfully organised to introduce molecular biology as an academic module to participants. Three participating Member States, namely United Arab Emirates (UAE), Nepal and Afghanistan have initiated processes to start the postgraduate master medical physics education programmes by coursework, adopting the IAEA TCS56 Guidelines. UAE has succeeded in completing the process while Nepal and Afghanistan have yet to initiate the programme. The postgraduate master medical physics programmes by coursework were strengthened in Indonesia, Jordan, Malaysia, Pakistan, Syria, and Thailand, along with the national registration of medical physicists. In particular, Thailand has revised 6 postgraduate master medical physics programmes by coursework during the tenure of this project. Home Based Assignment and RTCs have resulted in two publications. In conclusion, the RAS6088 project was found to have achieved its planned outcomes despite challenges faced due to the COVID-19 pandemic. It is proposed that a follow up project be implemented to increase the number of Member States who are better prepared to improve medical physics education and training in the region.

Estimating brain and eye lens dose for the cardiologist in interventional cardiology-are the dose levels of concern?

OBJECTIVES: To establish conversion coefficients (CCs), between mean absorbed dose to the brain and eye lens of the cardiologist and the air kerma-area product, PKA, for a set of projections in cardiac interventional procedures. Furthermore, by taking clinical data into account, a method to estimate the doses per procedure, or annual dose, is presented. METHODS: Thermoluminescence dosimeters were used together with anthropomorphic phantoms, simulating a cardiologist performing an interventional cardiac procedure, to estimate the CCs for the brain and eye lens dose for nine standard projections, and change in patient size and x-ray spectrum. Additionally, a single CC has been estimated, accounting for each projections fraction of use in the clinic and associated PKA using clinical data from the dose monitoring system in our hospital. RESULTS: The maximum CCs for the eye lens and segment of the brain, is 5.47 µGy/Gycm2 (left eye lens) and 1.71 µGy/Gycm2 (left brain segment). The corresponding weighted CCs: are 3.39 µGy/Gycm2 and 0.89 µGy/Gycm2, respectively. CONCLUSIONS: Conversion coefficients have been established under actual scatter conditions, showing higher doses on the left side of the operator. Using modern interventional x-ray equipment, interventional cardiac procedures will not cause high radiation dose levels to the operator when a ceiling mounted shield is used, otherwise there is a risk that the threshold dose values for cataract will be reached. ADVANCE IN KNOWLEDGE: In addition to the CCs for the different projections, methods for deriving a single CC per cardiac interventional procedure and dose per year were introduced.

Quality Assurance Considerations in Radiopharmaceutical Therapy Dosimetry Using PLANETDose: An International Atomic Energy Agency Study.

Implementation of radiopharmaceutical therapy dosimetry varies depending on the clinical application, dosimetry protocol, software, and ultimately the operator. Assessing clinical dosimetry accuracy and precision is therefore a challenging task. This work emphasizes some pitfalls encountered during a structured analysis, performed on a single-patient dataset consisting of SPECT/CT images by various participants using a standard protocol and clinically approved commercial software. Methods: The clinical dataset consisted of the dosimetric study of a patient administered with [177Lu]Lu-DOTATATE at Tygerberg Hospital, South Africa, as a part of International Atomic Energy Agency-coordinated research project E23005. SPECT/CT images were acquired at 5 time points postinjection. Patient and calibration images were reconstructed on a workstation, and a calibration factor of 122.6 Bq/count was derived independently and provided to the participants. A standard dosimetric protocol was defined, and PLANETDose (version 3.1.1) software was installed at 9 centers to perform the dosimetry of 3 treatment cycles. The protocol included rigid image registration, segmentation (semimanual for organs, activity threshold for tumors), and dose voxel kernel convolution of activity followed by absorbed dose (AD) rate integration to obtain the ADs. Iterations of the protocol were performed by participants individually and within collective training, the results of which were analyzed for dosimetric variability, as well as for quality assurance and error analysis. Intermediary checkpoints were developed to understand possible sources of variation and to differentiate user error from legitimate user variability. Results: Initial dosimetric results for organs (liver and kidneys) and lesions showed considerable interoperator variability. Not only was the generation of intermediate checkpoints such as total counts, volumes, and activity required, but also activity-to-count ratio, activity concentration, and AD rate-to-activity concentration ratio to determine the source of variability. Conclusion: When the same patient dataset was analyzed using the same dosimetry procedure and software, significant disparities were observed in the results despite multiple sessions of training and feedback. Variations due to human error could be minimized or avoided by performing intensive training sessions, establishing intermediate checkpoints, conducting sanity checks, and cross-validating results across physicists or with standardized datasets. This finding promotes the development of quality assurance in clinical dosimetry.

The IAEA remote and automated quality control methodology for radiography and mammography.

Radiography remains the most widely used imaging modality throughout the world. Additionally, while it has been demonstrated that a quality control (QC) program, especially in mammography, improves image quality, weekly technologist QC testing might be lacking even where there is clinical qualified medical physicist (CQMP) support. Therefore, the International Atomic Energy Agency (IAEA) developed simple QC phantoms that can easily be used on a regular basis (daily/weekly) for radiography and mammography. These are simple in design and use materials that are easily accessible in most parts of the world. A software application is also developed that automatically analyzes images and Digital Imaging and Communications in Medicine (DICOM) header information. It exports data to a comma-separated values (CSV) file that is read by a Microsoft Excel® spreadsheet for documentation and graphical analysis. The phantom and the software were tested in four institutions (in Costa Rica and the United States of America) both on computed radiography and direct digital mammography and radiography systems. Data were collected over a 3-year period. No corrective actions were taken on the data, but service was performed on two of the units. Results demonstrated noise that could be attributed to suboptimal placement of the phantom and incorrect data being put into the DICOM header. Preliminary evaluation of the IAEA methodology has demonstrated that it can provide meaningful QC data that are sensitive to changes in the imaging systems. Care must be taken at implementation to properly train personnel and ensure that the image data, including the DICOM header, are being correctly transmitted. The methodology gives the opportunity for a single CQMP to provide QC services even to remote sites where travel is prohibitive, and it is feasible and easy to implement.

Radiation dose and diagnostic reference levels for four interventional radiology procedures: results of the prospective European multicenter survey EUCLID.

OBJECTIVES: To assess information reflecting radiation dose and define diagnostic reference levels (DRL) on a European basis for four interventional radiology (IR) procedures considering clinical indication, anatomical region, and procedure. METHODS: A prospective European study was performed to provide data on the IR procedures percutaneous recanalization of iliac arteries, percutaneous recanalization of femoropopliteal arteries, transarterial chemoembolization of hepatocellular carcinoma, and percutaneous transhepatic biliary drainage. Hospitals were asked to complete a questionnaire giving information on procedure, equipment, and protocol. Patient size and weight, experience of the operator graded in number of procedures performed, and complexity level of each procedure were reported. Sixteen hospitals from 13 countries could be surveyed. The percentiles of the kerma-area product, fluoroscopy time, cumulative air kerma at the interventional reference point, and number of images were determined. The impact of equipment, year of installation, and complexity level of the procedure on dose were analyzed. RESULTS: DRLs based on clinical indication were defined. Dose values varied considerably within hospitals, between them, and within each subgroup of complexity level. The use of state-of-the-art equipment reduced dose significantly by 52%. Although dose also varied within each subgroup of complexity level, for transarterial chemoembolization of hepatocellular carcinoma and percutaneous transhepatic biliary drainage, dose significantly correlated with complexity. CONCLUSIONS: This was the first study reporting exposure practice and defining DRLs based on clinical indication for four IR procedures on a European basis. These DRLs can serve as a baseline for comparison with local practice, the study as a guideline for future surveys. KEY POINTS: • The use of state-of-the-art angiographic equipment reduces dose significantly. • A significant correlation between radiation dose and complexity level is found. • Dose values vary considerably, both within and between individual hospitals, and within each complexity level of interventional radiology procedure.

CT diagnostic reference levels based on clinical indications: results of a large-scale European survey.

OBJECTIVES: The objective of this study was to investigate the feasibility of defining diagnostic reference levels (DRLs) on a European basis for specific clinical indications (CIs), within the context of the European Clinical DRLs (EUCLID) European Commission project. METHODS: A prospective, multicenter, industry-independent European study was performed to provide data on 10 CIs (stroke, chronic sinusitis, cervical spine trauma, pulmonary embolism, coronary calcium scoring, coronary angiography, lung cancer, hepatocellular carcinoma, colic/abdominal pain, and appendicitis) via an online survey that included information on patient clinical, technical, and dosimetric parameters. Data from at least 20 patients per CI were requested from each hospital. To establish DRLs, a methodology in line with the International Commission on Radiological Protection (ICRP) Report 135 good practice recommendations was followed. RESULTS: Data were collected from 19 hospitals in 14 European countries on 4299 adult patients and 10 CIs to determine DRLs. DRLs differ considerably between sites for the same CI. Differences were attributed mainly to technical protocol and variable number of phases/scan lengths. Stroke and hepatocellular carcinoma were the CIs with the highest DRLs. Coronary calcium scoring had the lowest DRL value. Comparison with published literature was limited, as there was scarce information on DRLs based on CI. CONCLUSIONS: This is the first study reporting on feasibility of establishing CT DRLs based on CI using European data. Resulting values will serve as a baseline for comparison with local radiological practice, national authorities when DRLs are set/updated, or as a guideline for local DRL establishment. KEY POINTS: • First study reporting on the feasibility of establishing CT diagnostic reference levels based on clinical indication using data collected across Europe. • Only one-fourth of the hospitals had CT machines less than 5 years old. • Large dose variations were observed among hospitals and CT protocols were quite different between hospitals.

Radiation dose management systems-requirements and recommendations for users from the ESR EuroSafe Imaging initiative.

The European Directive 2013/59/Euratom requires member states of the European Union to ensure justification and optimisation of radiological procedures and store information on patient exposure for analysis and quality assurance. The EuroSafe Imaging campaign of the European Society of Radiology created a working group (WG) on "Dose Management" with the aim to provide European recommendations on the implementation of dose management systems (DMS) in clinical practice. The WG follows Action 4: "Promote dose management systems to establish local, national, and European diagnostic reference levels (DRL)" of the EuroSafe Imaging Call for Action 2018. DMS are designed for medical practitioners, radiographers, medical physics experts (MPE) and other health professionals involved in imaging to support their tasks and duties of radiation protection in accordance with local and national requirements. The WG analysed requirements and critical points when installing a DMS and classified the individual functions at different performance levels. KEY POINTS: • DMS are very helpful software tools for monitoring patient exposure, optimisation, compliance with DRLs and quality assurance. • DMS can help to fulfil dosimetric aspects of the European Directive 2013/59/Euratom. • The EuroSafe WG analyses DMS requirements and gives recommendations for users.

Radiation dose optimization in diagnostic and interventional radiology: Current issues and future perspectives.

The medical radiological imaging technological evolution and wide availability has resulted in the exponential increase in utilization. Evidence for a risk of cancer arising from radiation doses of lower than 100 mSv is still limited. There is a need for patient dose optimization. A literature review was conducted to identify the reasons why optimization is important and the steps to be followed for a successful optimization process in digital radiology, Computed Tomography, interventional radiology and mammography. Based on recent literature, 5 steps for a dose optimization process are proposed. These steps are: 1) establishment of a quality assurance programme; a mistake, misuse or malfunction of an X-ray machine can potentially affect the health or life of thousands of people, 2) establishment of a dose optimization team consisting of a radiologist, medical physicist and radiation technologist, 3) determination of baseline dose levels and image quality as well as comparisons with benchmarks to decide which exam protocols should be optimized, 4) modification of protocols by the medical physicist and 5) evaluation of the optimization process and its effect on patient dose and image quality. The optimization process should include joint efforts focused on 1) equipment performance 2) exam protocol customization and 3) staff behaviour. Manufacturers should provide detailed descriptions of exam protocols and training on the use of dose reduction features. The diagnostic radiology medical physicist should emerge and take a proactive lead in the everyday clinical routine in order to promote the value of optimization process.

Development of breast lesions models database.

PURPOSE: We present the development and the current state of the MaXIMA Breast Lesions Models Database, which is intended to provide researchers with both segmented and mathematical computer-based breast lesion models with realistic shape. METHODS: The database contains various 3D images of breast lesions of irregular shapes, collected from routine patient examinations or dedicated scientific experiments. It also contains images of simulated tumour models. In order to extract the 3D shapes of the breast cancers from patient images, an in-house segmentation algorithm was developed for the analysis of 50 tomosynthesis sets from patients diagnosed with malignant and benign lesions. In addition, computed tomography (CT) scans of three breast mastectomy cases were added, as well as five whole-body CT scans. The segmentation algorithm includes a series of image processing operations and region-growing techniques with minimal interaction from the user, with the purpose of finding and segmenting the areas of the lesion. Mathematically modelled computational breast lesions, also stored in the database, are based on the 3D random walk approach. RESULTS: The MaXIMA Imaging Database currently contains 50 breast cancer models obtained by segmentation of 3D patient breast tomosynthesis images; 8 models obtained by segmentation of whole body and breast cadavers CT images; and 80 models based on a mathematical algorithm. Each record in the database is supported with relevant information. Two applications of the database are highlighted: inserting the lesions into computationally generated breast phantoms and an approach in generating mammography images with variously shaped breast lesion models from the database for evaluation purposes. Both cases demonstrate the implementation of multiple scenarios and of an unlimited number of cases, which can be used for further software modelling and investigation of breast imaging techniques. The created database interface is web-based, user friendly and is intended to be made freely accessible through internet after the completion of the MaXIMA project. CONCLUSIONS: The developed database will serve as an imaging data source for researchers, working on breast diagnostic imaging and on improving early breast cancer detection techniques, using existing or newly developed imaging modalities.

Gender-related differences in side-effects and hemodynamic response to regadenoson in patients undergoing SPECT myocardial perfusion imaging.

PURPOSE: To evaluate differences in side-effects and hemodynamic response between men and women undergoing regadenoson-stress SPECT myocardial perfusion imaging (MPI). METHODS: The initial population of the study included 858 consecutive patients who underwent regadenoson-stress MPI at our institution. These patients underwent prospective assessment and classification of regadenoson-induced side-effects in six categories and recording of heart rate (HR) and blood pressure (BP) before and after regadenoson administration. From this initial population, after adjustment with 1:1 propensity matching using gender as the dependent variable and age, BMI, diabetes mellitus, hypertension, smoking, presence of coronary artery disease, LVEF, baseline systolic and diastolic blood pressure (BP) and HR, on-going use of cardio-active medications during test, and abnormal MPI scan as independent variables, a population of 279 pairs of opposite gender was formed and studied. RESULTS: Compared with men, women had a significantly higher rate of any side-effect (71% vs. 58%, p = 0.002), chest pain (23% vs. 12%, p < 0.001), gastrointestinal discomfort (20% vs. 12%, p = 0.01), dizziness (12% vs. 5%, p = 0.002), and headache (20% vs. 13%, p = 0.03) and similar rates of dyspnea and other side-effects. Women demonstrated a higher median HR-response compared with men (41% (- 8, 127) vs. 34% (- 5, 106), p = 0.001) while men demonstrated a lower median systolic BP response (- 3% (- 27, 48) vs. 0% (- 36, 68), p = 0.02) compared with women. CONCLUSIONS: Gender is independently associated with a differential response to regadenoson with regard to overall side-effects and HR-response. These observations have the potential of important management and prognostic implications respectively.

EFOMP policy statement 16: The role and competences of medical physicists and medical physics experts under 2013/59/EURATOM.

On 5 December 2013 the European Council promulgated Directive 2013/59/EURATOM. This Directive is important for Medical Physicists and Medical Physics Experts as it puts the profession on solid foundations and describes it more comprehensively. Much commentary regarding the role and competences has been developed in the context of the European Commission project "European Guidelines on the Medical Physics Expert" published as Radiation Protection Report RP174. The guidelines elaborate on the role and responsibilities under 2013/59/EURATOM in terms of a mission statement and competence profile in the specialty areas of Medical Physics relating to medical radiological services, namely Diagnostic and Interventional Radiology, Radiation Oncology and Nuclear Medicine. The present policy statement summarises the provisions of Directive 2013/59/EURATOM regarding the role and competences, reiterates the results of the European Guidelines on the Medical Physics Expert document relating to role and competences of the profession and provides additional commentary regarding further issues arising following the publication of the RP174 guidelines.

22nd International Conference on Medical Physics 2016, Bangkok, Thailand; Medical physics propelling global health.

As medical technology evolves and patient needs increase, the need for well-trained and highly professional medical physicists (MPs) becomes even more urgent. The roles and responsibilities of MPs in various departments within the hospital are diverse and demanding. It is obvious that training, continuing education and professional development of MPs have become essential. One of the ways for an MP to advance his or her knowledge is to participate in conferences and congresses. Last year, the 22nd International Conference of Medical Physics (ICMP 2016) took place in Bangkok, Thailand. The event attracted 584 delegates with most of the participants coming from Asia. It attracted also delegates from 42 countries. The largest delegations were from Thailand, Japan and South Korea. ICMP 2016 included 367 oral presentations and e-posters, most of these being in the fields of Radiation Therapy, Medical Imaging and Radiation Safety. All abstracts were published as an e-book of Abstracts in a supplement to the official IOMP Journal. Many companies had exhibition stands at ICMP2016, thus allowing the participants to see the latest developments in the medical physics-related industry. The conference included 42 mini-symposia, part of the first "IOMP School" activity, covering various topics of importance for the profession and this special issue follows from the success of the conference.

1st European Congress of Medical Physics September 1-4, 2016; Medical Physics innovation and vision within Europe and beyond.

Medical Physics is the scientific healthcare profession concerned with the application of the concepts and methods of physics in medicine. The European Federation of Organisations for Medical Physics (EFOMP) acts as the umbrella organization for European Medical Physics societies. Due to the rapid advancements in related scientific fields, medical physicists must have continuous education through workshops, training courses, conferences, and congresses during their professional life. The latest developments related to this increasingly significant medical speciality were presented during the 1st European Congress of Medical Physics 2016, held in Athens, September 1-4, 2016, organized by EFOMP, hosted by the Hellenic Association of Medical Physicists (HAMP), and summarized in the current volume.

Does clinical indication play a role in CT radiation dose in pediatric patients?

PURPOSE: The purpose of this study was to identify the main pathologies for which CT is applied on pediatric patients and the related radiation doses as reported in the literature in order to facilitate justification and CT optimization. METHODS: A critical analysis of a literature review was performed. Different search engines were used such as PubMed, Google Scholar and Science Direct. Various terms and keywords were used to locate pertinent articles such as Pediatric, Computed tomography, Radiation Dose, Organ dose, Effective dose. RESULTS: The results showed that the main pathologies for which CT is applied are: Crohn's disease, hydrocephalus, cystic fibrosis and pediatric malignancies-mainly lymphoma. The related radiation dose data are extremely scarce and are in the range of 3.48-17.56, 0.2-15.3mSv, 0.14-6.20mSv, and 2.8-518.0mSv, respectively. The radiation doses reported are high especially in pediatric oncology. CONCLUSIONS: Pediatric patients with malignancies are those exposed to the higher levels of radiation during CT imaging. Literature is lacking reporting of dose in Pediatric CT imaging. More studies need to be realized for the determination of radiation dose in those patients. Special protocols need to be recommended in order to reduce the exposure of children in radiation.

Medical Physics: Forming and testing solutions to clinical problems.

According to the European Federation of Organizations for Medical Physics (EFOMP) policy statement No. 13, "The rapid advance in the use of highly sophisticated equipment and procedures in the medical field increasingly depends on information and communication technology. In spite of the fact that the safety and quality of such technology is vigorously tested before it is placed on the market, it often turns out that the safety and quality is not sufficient when used under hospital working conditions. To improve safety and quality for patient and users, additional safeguards and related monitoring, as well as measures to enhance quality, are required. Furthermore a large number of accidents and incidents happen every year in hospitals and as a consequence a number of patients die or are injured. Medical Physicists are well positioned to contribute towards preventing these kinds of events". The newest developments related to this increasingly important medical speciality were presented during the 8th European Conference of Medical Physics 2014 which was held in Athens, 11-13 September 2014 and hosted by the Hellenic Association of Medical Physicists (HAMP) in collaboration with the EFOMP and are summarized in this issue.

Impact of the International Atomic Energy Agency (IAEA) actions on radiation protection of patients in many countries.

In the 1990s, there was a lack of information on patient doses in most developing countries. In 2004, the International Atomic Energy Agency initiated projects aimed at assessing 'how safe are patients in radiological procedures and how to make them safer'. The major obstacle was a lack of medical physicists with patient dosimetry skills and a lack of dosimetry facilities. Actions taken were such as to yield results within a short span of time and a number of publications with interesting findings. Results showed that while patient doses in radiography are largely within diagnostic reference levels (DRLs), poor image quality is rampant. In mammography, CT and interventional procedures, doses higher than DRLs were observed. Dose management actions were implemented and significant improvements emerged. Utilising existing manpower (physicists, regulators, radiographers, radiologists), preparing detailed guidelines and data collection forms, focussing training on acquiring dosimetry skills, a system of periodic reports with mentoring and motivating collaborations within each country are some of the reasons for the success of the project.

Status of radiation protection in various interventional cardiology procedures in the Asia Pacific region.

OBJECTIVE: Increasing use of interventional procedures in cardiology with unknown levels of radiation protection in many countries of Asia-Pacific region necessitates the need for status assessment. The study was part of an International Atomic Energy Agency (IAEA) project for achieving improved radiation protection in interventional cardiology (IC) in developing countries. DESIGN: The survey covers 18 cardiac catheterisation laboratories in seven countries (Bangladesh, India, Malaysia, Myanmar, Singapore, Thailand and Vietnam). An important step was the creation of the 'Asian network of Cardiologists in Radiation Protection' and a newsletter. Data were collected on: radiation protection tools, number of IC laboratories, and annual number of various IC paediatric and adult procedures in the hospital and in the country. Patient radiation dose data were collected in terms of Kerma Area Product (KAP) and cumulative dose (CD). RESULTS: It is encouraging that protection devices for staff are largely used in the routine practice. Only 39% of the angiographic machines were equipped with a KAP meter. Operators' initial lack of awareness on radiation-protection optimisation improved significantly after participation in IAEA radiation-protection training. Only two out of five countries reporting patient percutaneous coronary intervention radiation-dose data were fully within the international guidance levels. Data from 51 patients who underwent multiple therapeutic procedures (median 2-3) indicated a total KAP reaching 995 Gy.cm(2) (range 10.1-995) and CD 15.1 Gy (range 0.4-15.1), stressing the importance of dose monitoring and optimisation. CONCLUSIONS: There is a need for interventional cardiology societies to play an active role in training actions and implementation of radiation protection.

Radiation safety in abdominal computed tomography.

The rapid technological developments in computed tomography (CT) have enabled many new clinical applications in the abdominal region. Abdomen CT is considered as a high radiation dose examination due to the large number of radiosensitive organs in the field of view. CT radiation dose has received a lot of attention not only by the medical specialties and researchers, but also by patients and media. This article reviews the situation on radiation dose and risk and provides practical guidelines to effectively manage the radiation dose without losing the benefits and maintaining diagnostic confidence in CT procedures.