The growing potential of diagnostic reference levels as a dynamic tool for dose optimization

Latiff R, Mohamad M. Investigating knowledge of DRLs, image quality and radiation dose in PET/CT and CT imaging among medical imaging professionals

Objective

To investigate the knowledge of diagnostic reference levels (DRLs), image quality, radiation dose and protocol parameters among Jordanian medical imaging professionals (MIPs) involved in PET/CT and CT scan procedures.

Materials and methods

A questionnaire was designed and distributed to MIPs in Jordan. The survey comprised four sections: demographic data, MIP knowledge on dose/protocol parameters, image quality, and DRLs. Statistical analyses were performed utilizing Pearson's correlation, t-tests, ANOVA, and linear regression, with a significance level of 95 % and a p-value threshold of <0.05.

Results

The study involved 147 participants. Most respondents were male (76.2 %), and most were aged 26-35 years (44.2 %). Approximately 51 % held a bachelor's degree, and the most common range of experience was 3-5 years (28.6 %). Participants showed a moderate level of knowledge regarding dose and protocol parameters, with a mean score of 61.8 %. The mean scores for knowledge of image quality and DRLs were 45.2 % and 44.8 %, respectively. The age group of the MIPs and the total experience were found to have a significant impact on the knowledge of the dose and protocol parameters, as well as the DRLs. Additionally, experience was found to have a significant influence on knowledge of the dose and protocol parameters. The study revealed a positive and significant effect of MIPs' knowledge of dose/protocol parameters and image quality on their knowledge of DRLs.

Conclusions

This study indicates that professionals across five specialties who are engaged in PET/CT and CT imaging possess a moderate understanding of dosage and protocol parameters. However, there is a notable gap in knowledge regarding DRLs and image quality. To address this issue, it is recommended that MIPs actively engage in educational programs emphasizing exposure parameters and their impact on image quality. Additionally, access to comprehensive education and training programs will enable MIPs to grasp the complexities of DRLs and their implications, facilitating their implementation in clinical practice.

Radiology's Ionising Radiation Paradox: Weighing the Indispensable Against the Detrimental in Medical Imaging

Ionising radiation stands as an indispensable protagonist in the narrative of medical imaging, underpinning diagnostic evaluations and therapeutic interventions across an array of medical conditions. However, this protagonist poses a paradox - its inestimable service to medicine coexists with an undercurrent of potential health risks, primarily DNA damage and subsequent oncogenesis. The narrative of this comprehensive review unfurls around this intricate enigma, delicately balancing the indispensable diagnostic utility against the non-negotiable commitment to patient safety. In this critical discourse, the intricacies of ionising radiation are dissected, illuminating not only its sources but also the associated biological and health hazards. The exploration delves into the labyrinth of strategies currently deployed to minimise exposure and safeguard patients. By casting light on the scientific nuances of X-rays, computed tomography (CT), and nuclear medicine, it traverses the complex terrain of radiation use in radiology, to promote safer medical imaging practices, and to facilitate an ongoing dialogue about diagnostic necessity and risk. Through a rigorous examination, the pivotal relationship between radiation dose and dose response is elucidated, unravelling the mechanisms of radiation injury and distinguishing between deterministic and stochastic effects. Moreover, protection strategies are illuminated, demystifying concepts such as justification, optimisation, the As Low As Reasonably Achievable (ALARA) principle, dose and diagnostic reference levels, along with administrative and regulatory approaches. With an eye on the horizon, promising avenues of future research are discussed. These encompass low-radiation imaging techniques, long-term risk assessment in large patient cohorts, and the transformative potential of artificial intelligence in dose optimisation. This exploration of the nuanced complexities of radiation use in radiology aims to foster a collaborative impetus towards safer medical imaging practices. It underscores the need for an ongoing dialogue around diagnostic necessity and risk, thereby advocating for a continual reassessment in the narrative of medical imaging.

CT doses based on clinical indications. New national DRL's in Iceland

A diagnostic reference level (DRL) is an investigation level to use in the optimization of a medical exposure using ionizing radiation. The aim of this project was to gather dose data from computed tomography (CT) studies in Iceland with the purpose of updating existing national DRL and proposing DRLs based on clinical indications. Dose data (total dose length product (DLP) and CT dose index) were retrospectively collected from all CT scanners in Iceland for 50 patients for all common CT studies. After cleaning the data, the data set contained total DLP for 8129 patients. Considering dose-relevant parameters such as the number of phases and scan length, each CT study was assigned to one of 42 study types and (at least) one clinical indication. Data were received from seven or more scanners for 13 clinical indications and from all scanners providing coronary angiography. There was considerable variation in the median total DLP from different scanners, e.g., from 13 to 139 mGycm for Sinusitis, and, the range of individual total DLPs varied between scanners. This underscores the importance of monitoring patients' exposure. The study shows that there is room for optimization. New Icelandic NDRLs were proposed for the total DLP of CT examinations based on ten different indications, including: Brain ischemia (1060 mGycm), Interstitial lung disease (310 mGycm) and Appendicitis (690 mGycm). The proposed NDRLs were the first clinical indication based NDRLs in Iceland. The Icelandic Radiation Safety Authority has decided to update the NDRLs based on the results of this study.

Establishment and utilization of diagnostic reference levels in medical imaging: Results from a survey and consultation under the IAEA technical cooperation programme in Europe and Central Asia

The paper presents the results of the activities under the IAEA Technical Cooperation programme in Europe and Central Asia, aiming to improve utilization of diagnostic reference levels (DRLs) in the region through identifying status, problems, and gaps in establishing and utilization of the DRLs, and suggesting potential solutions. Status was identified through a survey with two electronic questionnaires answered by the regulatory bodies for radiation protection of 26 IAEA Member States and 34 representatives of relevant professional bodies of medical physics, radiology, nuclear medicine or radiographers. Problems, good practices and potential solutions were identified as a result of the discussion during a regional workshop with 50 nominated representatives of 21 countries. Results were disseminated through open webinars. Existing gaps are related to the lack of adequate regulations in some countries, inadequate awareness of radiological professionals of DRLs as a tool for optimization, insufficient cooperation among relevant stakeholders, education, and staffing. Strengthening of the cooperation between regulatory and professional bodies could benefit the awareness and consequently the utilization of DRLs in clinical practice. The need of improved education and training of the DRL process was highlighted. Improved inspection procedures and education of inspectors would also support the process. Access to clinically qualified medical physicists was found to be critical for the DRL utilization. Suggestions were placed for continuous IAEA assistance through training, guidance and expert support.

How to establish and use local diagnostic reference levels: an ESR EuroSafe Imaging expert statement

Abstract

Although the Diagnostic Reference Levels (DRLs) have been shown to be an important tool for optimising patient radiation protection, there are still difficulties related to the methodology that should be used to establish and use local DRL values. This statement represents the current view of the EuroSafe Imaging ‘Clinical DRLs’ working group formed with the purpose to produce scientific and educational material on DRLs and promote the concept of local DRLs. Guidelines on how to establish and how to use local DRLs presented herein can be implemented using a multidisciplinary team approach. Local DRLs are easy to determine and implement and they reflect local equipment performance and local clinical needs. They can be updated more frequently than the national DRLs, especially if a dose management system is available. To establish local DRLs, a practical approach could be to collect a reasonable set, i.e., at least 20–30 procedures, of data for well-defined clinical indications and calculate the 3rd quartile values. The median values of the distribution can be set to define the ‘typical values’. The International Commission of Radiological Protection (ICRP) suggests setting ‘typical values’ for newer technologies that enable decreased amounts of radiation exposure for a similar level of image quality. Local DRLs should be similar or lower to the national DRLs. They could be higher only if the clinical benefits for some medical indications are fully explained and reported. Local DRLs may be used as a quality benchmark to track outliers and can be also used as alert values.

Key points

Guidelines on how to establish and use local DRLs are presented.

Local DRLs are easy to determine and implement and can be updated frequently

Additionally, local DRLs can be used to track outliers.

Local reference and achievable dose levels for vascular and enterostomy access procedures in pediatric interventional radiology

BACKGROUND

Knowledge of radiation quantities delivered in routine practice is an essential responsibility of a pediatric interventional radiology department.

OBJECTIVE

To review radiation indices in frequently performed vascular and enterostomy access procedures at a quaternary pediatric hospital to formulate dosimetric reference levels and achievable levels.

MATERIALS AND METHODS

A retrospective review of patient demographics, procedure information and quantitative dose metrics over a 2-year period was performed. Dosimetric details for common procedures (central line insertions, gastrostomy/gastrojejunostomy insertions and maintenance) were evaluated, correlated with demographic data and stratified across five weight groups (0-5 kg, 5-15 kg, 15-30 kg, 30-50 kg, 50-80 kg). Achievable (50th percentile) and reference (75th percentile) levels with confidence intervals were established for each procedure.

RESULTS

Within the evaluation period, 3,165 studies satisfied the inclusion criteria. Five were classified as device insertions (peripherally inserted central catheter, n=1,145; port-a-catheter, n=321; central venous line, n=285; gastrostomy-tube [G-tube], n=262, and gastrojejunostomy-tube [GJ-tube], n=66), and two were classified as maintenance procedures (G-tube, n=358, and GJ-tube, n=728, checks, exchanges and reinsertions). Representative reference and achievable levels were calculated for each procedure category and weight group.

CONCLUSION

This work highlights the creation of local reference and achievable levels for common pediatric interventional procedures. These data establish a dosimetric reference to understand the quantity of radiation routinely applied, allowing for improved relative radiation risk assessment and enriched communication to interventionalists, health care providers, parents and patients.

The Impact of Data Management on the Achievable Dose and Efficiency of Mammography and Radiography During the COVID-19 Era: A Facility-Based Cohort Study

Purpose

To evaluate the impact of using computational data management resources and analytical software on radiation doses in mammography and radiography during the COVID-19 pandemic, develop departmental diagnostic reference levels (DRLs), and describe achievable doses (ADs) for mammography and radiography based on measured dose parameters.

Patients and Methods

This ambispective cohort study enrolled 795 and 12,115 patients who underwent mammography and radiography, respectively, at the King Fahd Hospital of the University, Al-Khobar City, Saudi Arabia between May 25 and November 4, 2021. Demographic data were acquired from patients' electronic medical charts. Data on mammographic and radiographic dose determinants were acquired from the data management software. Based on the time when the data management software was operational in the institute, the study was divided into the pre-implementation and post-implementation phases. Continuous and categorical variables were compared between the two phases using an unpaired t-test and the chi-square test.

Results

The median accumulated average glandular dose (AGD; a mammographic dose determinant) in the post-implementation phase was three-fold higher than that in the pre-implementation phase. The average mammographic exposure time in the post-implementation phase was 16.3 ms shorter than that in the pre-implementation phase. Furthermore, the median values of the dose area product ([DAP], a radiographic dose determinant) were 9.72 and 19.4 cGycm² in the pre-implementation and post-implementation phases, respectively.

Conclusion

Although the data management software used in this study helped reduce the radiation exposure time by 16.3 ms in mammography, its impact on the mean accumulated AGD was unfavorable. Similarly, radiographic exposure indices, including DAP, tube voltage, tube current, and exposure time, were not significantly different after the data management software was implemented. Close monitoring of patient radiation doses in mammography and radiography, and dose reduction will become possible if imaging facilities use DRLs and ADs via automated systems.

Patient size as a parameter for determining Diagnostic Reference Levels for paediatric Computed Tomography (CT) procedures

INTRODUCTION

The paediatric radiation dose has never been studied in Sri Lanka, nor has a national diagnostic reference level (NDRL) established. Therefore, the primary aim of this study was to propose diagnostic reference levels (DRL) and achievable dose (AD) values for paediatric CT examinations based on size.

METHODS

A total of 658 paediatric (0-15 years) non-contrast-enhanced (NC) studies of head, chest and abdomen regions performed during six months in two dedicated paediatric hospitals (out of the three such institutions in the country) were included. For head examinations, the dose indexes were analysed based on age, while for body examinations, both age and effective diameter (D_eff) were used. The median and the third quartile of the pooled dose distribution were given as AD and NDRL, respectively.

RESULTS

The AD ranges for the head, chest and abdomen regions based on CTDI_vol were 45.8-57.2 mGy, 2.9-10.0 mGy and 3.8-10.3 mGy. The corresponding NDRL ranges were 45.8-95.8 mGy, 3.5-14.1 mGy and 4.5-11.9 mGy. The AD ranges based on SSDE_deff and d_eff were 3.5-9.6 mGy and 4.1-10.3 mGy in chest and abdomen regions. The corresponding NDRL were 4.5-14.1 mGy and 6.1-10.6 mGy.

CONCLUSION

Other institutions can use the present study DRLs as a reference dose for paediatric CT. The AD values can be used as a baseline for target dose optimisations, reducing doses up to 90%.

Size-specific dose estimates for pediatric head CT protocols based on the AAPM report TG-293

PURPOSE

To establish the Size Specific Dose Estimate (SSDE) typical values for pediatric head CT examinations based on the AAPM report TG-293; to provide a new stratification based on the water-equivalent diameter (D_w), given that SSDE is related to the head size.

METHODS

296 Head CT scans of pediatric patients collected using a dose monitoring software were retrospectively analysed. Typical values were derived stratifying data by age in three methods: the first proposed by the European Guidelines on Diagnostic Reference Levels for Pediatric Imaging (RP185), the second by the National Istisan Report 20/22 and a local one related to the clinical protocols (LStrata). For each scan, a self-developed Matlab routine calculated the water-equivalent diameter (D_w) and related SSDE values with the conversion factors f^H16and f^B16provided by the AAPM reports TG-293 and TG-204, respectively. Eventually, a D_wstratification was introduced starting from a measure of the lateral dimension of the head.

RESULTS

SSDE based on TG-204 overestimatesthe dose up to 12%. Four D_wgroups were identified thanks to the good correlation between the head lateral dimension andD_w: D_w < 14 cm, 14 ≤ D_w < 16 cm, 16 ≤ D_w< 17 cm, D_w≥ 17 cm. The D_w-stratified dosimetric indices presentgreater variability than those grouped by age because of the large variability of the size of the infant's head.

CONCLUSIONS

The variability of the SSDE metric underlines that age-optimized protocols are not when size is considered.

Diagnostic reference levels during fluoroscopically guided interventions using mobile C-arms in operating rooms: A national multicentric survey

PURPOSE

To establish diagnostic reference levels (DRLs) and achievable levels (ALs) for the most common fluoroscopically guided interventions (FGIs) performed in operating rooms using mobile C-arm equipment.

METHODS

A national survey was performed in 57 centers in France. Anonymous data from 6817 patients undergoing FGIs were prospectively collected over a period of 7 months. DRLs (third quartile of the distribution) and ALs (median of the distribution) were determined for each type of intervention in terms of kerma area product (KAP) and fluoroscopy time (FT).

RESULTS

DRLs and ALs were proposed for 31 procedure types related to seven surgical specialties: orthopedics (n = 9), urology (n = 3), vascular (n = 6), cardiology (n = 5), neurosurgery (n = 3), gastrointestinal (n = 3), and multi-specialty (n = 2). DRLs in terms of KAP ranged from 0.1 Gy·cm² for hallux valgus to 78 Gy·cm² for abdominal aortic aneurysm endovascular repair. A factor of 155 was obtained between the FTs for a herniated lumbar disk (0.2 min) and an abdominal aortic aneurysm endovascular repair (31 min). The highest variations were obtained within orthopedic procedures in terms of KAP (ratio 122) and within gastrointestinal procedures in terms of FT (ratio 9). Overall, the FGIs associated with the highest radiation exposure (KAP > 10 Gy·cm²) were found in the cardiology, vascular, and gastrointestinal specialties.

CONCLUSIONS

DRLs and ALs are suggested for a wide range of FGIs performed in operating rooms using a mobile C-arm. We aim at providing a practical optimization tool for medical physicists and surgeons.