Objectives
To describe first experience of integrating assessment of image quality in paediatric X-ray computed tomography (CT) with analysis of the radiation dose indices to develop reference doses ...called acceptable quality dose (AQD).
Methods
Image quality was scored by the radiologists at a tertiary care hospital in Qatar on a scale of 0 to 4 using the recently published scoring criteria. The patients undergoing head, chest and abdomen CT were divided in different weight groups as follows: < 5 kg, 5–< 15 kg, 15–< 30 kg, 30–< 50 kg, 50–< 80 kg and > 80 kg. The images that were clinically acceptable (score of 3) were included for assessment of median values of CTDIvol and DLP to obtain AQDs in different weight groups.
Results
After initial training in image quality scoring of CT images of 49 patients by three radiologists, the study on 715 patients indicated 665 studies (93%) were clinically acceptable as per scoring criteria. The median CTDI
vol
values for the above weight groups were 16, 20, 22, 22, 27 and 27 mGy and the median DLP values for these weight groups were 271, 377, 463, 486, 568 and 570 mGy cm, respectively, for head CT. Similar values are presented for chest and abdomen CTs.
Conclusions
The first ever experience of starting with image quality assessment and integrating it with analysis of dose indices to obtain AQD values shall provide a workable model for others and values for comparison within the facility and in other facilities leading to optimisation.
Key Points
•
The first study to integrate image quality assessment with analysis of patient dose indices shows feasibility for routine practice in other centres.
•
The values of acceptable quality dose (AQD) were provided for head, chest and abdomen CT of children divided into weight groups rather than age. They shall act as reference values for future studies.
•
Verification of our findings on proportional increase in exposure parameters (CTDIvol and DLP) with weight by other investigators shall be helpful.
•CT contributes to the majority of radiation dose associated with diagnostic imaging procedures.•Substantial variations in scan protocols and radiation doses necessitate monitoring of CT ...doses.•Commercial radiation dose monitoring software capture information on scan factors and dose indices.•Users must understand the strengths, applications and limitations of dose monitoring software.
In the last few years there has been an increasing interest on radiation dose to patients undergoing various diagnostic or therapeutic procedures with the use of ionizing radiation. Especially for CT examinations and interventional procedures, where it is known that patient doses are much higher than conventional radiography, new norms have been published that require to have appropriate radiation dose indices registered in the patient medical record. Because of these demands, dose monitoring has been recommended and adopted into many clinical practices as a routine procedure for every patient and every examination. Dedicated dose monitoring systems (DMS) that facilitate data collection and processing, statistical comparisons, reporting and management of radiation dose related information have been devised and are being used worldwide.
In this review paper, a brief flashback to the reasons that necessitated dose monitoring in radiology will be first presented. Furthermore, since the focus of this manuscript is on CT, the CT dosimetry principles and metrics will be summarized. The limitations of these metrics will be also discussed, so that DMS users are aware of the semantics of the parameters shown in the DMS reports. The operation of DMS systems will be outlined to make users aware of functions, limitations, and available options of DMS systems. Furthermore, the usefulness of DMS systems as an optimization tool will be presented and discussed. Finally, information about the DMS solutions available in the market and relevant links will be presented.
The purpose of our study was to investigate the level of radiation protection of patients and staff during interventional procedures in 20 countries of Africa, Asia, and Europe.
In a multinational ...prospective study, information on radiation protection tools, peak skin dose (PSD), and kerma-area product (KAP) was provided by 55 hospitals in 20 mainly developing countries (nine mostly in Eastern Europe, five in Africa, and six in Asia).
Nearly 40% of the interventional rooms had an annual workload of more than 2,000 patients. It is remarkable that the workload of pediatric interventional procedures can reach the levels of adult procedures even in developing countries. About 30% of participating countries have shown a 100% increase in workload in 3 years. Lead aprons are used in all participating rooms. Even though KAP was available in almost half of the facilities, none had experience in its use. One hundred of 505 patients monitored for PSD (20%) were above the 2-Gy threshold for deterministic effects.
Interventional procedures are increasing in developing countries, not only for adults but also for pediatric patients. The situation with respect to staff protection is considered generally acceptable, but this is not the case for patient protection. Many patients exceeded the dose threshold for erythema. A substantial number (62%) of percutaneous transluminal coronary angioplasty procedures performed in developing countries in this study are above the currently known dose reference level and thus could be optimized. Therefore, this study has significance in introducing the concept of patient dose estimation and dose management.
•This is the first study in the Asian region and one of the very few that established DRLs based on clinical indication for CT.•Standardized CI nomenclature must be established as there are no ...guidelines for accurate comparison between studies on CT patient exposure.•The established clinical DRL values for CT will further facilitate patient dose optimization and quality improvement process HMC in Qatar.
The objectives of this study were to: 1) evaluate patient radiation exposure in CT and 2) establish CT Diagnostic Reference Levels (DRL)s based on clinical indication (CI) in Qatar.
Patient data for 13 CIs were collected using specially designed collection forms from the dose management software (DMS) of Hamad Medical Corporation (HMC), the main Qatar healthcare provider. The methodology described in the International Commission on Radiological Protection (ICRP) Report 135 was followed to establish national clinical DRLs in terms of Volumetric Computed Tomography Dose Index (CTDIvol) and total Dose Length Product (DLPt). Effective dose (Ef) was estimated by DMS using DLPt and appropriate conversion factors and was analyzed for comparison purposes.
Data were retrospectively collected for 896 adult patients undergoing CT examinations in 4 hospitals and 7 CT scanners. CT for Diffuse infiltrative lung disease imparted the lowest radiation in terms of CTDIvol (5 mGy), DLPt (181 mGy.cm) and Ef (3.6 mSv). Total body CT for severe trauma imparted the highest DLPt (3137 mGy.cm) and Ef (38.6 mSv) of all CIs with a CTDIvol of 15 mGy. Rounded Third quartile CTDIvol and DLPt values were defined as the Qatar CT clinical DRLs. Comparison was limited due to sparse international literature. When this was possible data were lower or comparable with other studies.
This is the first study reporting national clinical DRLs in Asia and second one internationally after UK. For accurate comparison between studies, systemized CI nomenclature must be followed by researchers.
Compared with other countries in the Middle East, Qatar has one of the highest breast cancer incidence and mortality rates. Poor quality mammography images may be associated with advanced stage ...breast cancer, however there is limited information about the quality of breast imaging in Qatar. Our purpose was to evaluate the clinical image quality of mammography examinations performed at a tertiary care center in Doha, Qatar using a standardized assessment tool.
Bilateral mammograms from consecutive patients from a tertiary care cancer center in Doha, Qatar were obtained. Proportions of examinations deemed adequate for interpretation were estimated. Standardized clinical image quality assessment form was utilized to evaluate image quality components. For each image, image quality components were given grades on a 1-5 scale (5-excellent, 4-good, 3-average, 2-fair, 1-poor). Mean scores with 95% confidence intervals were estimated for each component.
Consecutive sample of 132 patients was obtained representing 528 mammographic images. Overall, 99.2% of patients underwent examinations rated as acceptable for interpretation. Mean scores for each image quality component ranged from 4.045 to 5.000 (lowest score for inframammary fold). Image quality component scores were 93.0% excellent, 5.2% good, 1.1% average, 0.6% fair, and 0.1% poor.
Overall image quality at a tertiary care center in Doha, Qatar was acceptable for interpretation with minimal areas identified for improvement.
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.
Nuclear medicine (NM) started in Qatar in the mid-1980s with a 1-head γ-camera in Hamad General Hospital. However, Qatar is expanding, and now Hamad Medical Corp. has 2 NM departments and 1 PET/CT ...Center for Diagnosis and Research, with several hybrid SPECT/CT and PET/CT cameras. Furthermore, 2 new NM departments will be established in Qatar in the coming 3 y. Therefore, there is a need to optimize radiation protection in NM imaging and establish diagnostic reference levels (DRLs) for the first time in Qatar. This need is not only for the NM part of the examination but also for the CT part, especially in hybrid SPECT/CT and PET/CT.
Data for adult patients were collected from the 3 SPECT/CT machines in the 2 NM facilities and from the 2 PET/CT machines in the PET/CT center. The 75th percentile values (also known as the third quartile) were considered preliminary DRLs and were consistent with the most commonly administered activities. The results for various general NM protocols were described, especially
Tc-based radiopharmaceuticals and PET/CT protocols including mainly oncologic applications.
The first DRLs for NM imaging in Qatar adults were established. The values agreed with other published DRLs, as was the case, for example, for PET oncology using
F-FDG, with DRLs of 258, 230, 370, 400, and 461-710 MBq for Qatar, Kuwait, Korea, the United Kingdom, and the United States, respectively. Similarly, for cardiac stress or rest myocardial perfusion imaging using
Tc-methoxyisobutylisonitrile, the DRLs were 926, 976, 1,110, 800, and 945-1,402 MBq for Qatar, Kuwait, Korea, the United Kingdom, and the United States, respectively.
The optimization of administered activity that this study will enable for NM procedures in Qatar will be of great value, especially for new departments that adhere to these DRLs.
•Radiation doses from most head CT were within the diagnostic reference levels.•Several children were scanned with longer than necessary scan lengths.•Radiation doses for pediatric head CT are ...linearly correlated with patient age (R3-1).
To evaluate the relationship between patient age and radiation doses associated with routine pediatric head CT performed with automatic tube potential selection and tube current modulation techniques.
We obtained patient demographics, scan parameters, and radiation dose descriptors (CT dose index volume -CTDIvol and dose length product -DLP) associated with consecutive routine head CT in 705 children (mean age 6.9 ± 5 years). Children were scanned on one of the three multidetector-row CTs (64–128 slices, Siemens) over 6 months period in a tertiary hospital. All head CT exams were performed in helical scan mode using automatic tube potential selection (Care kV) and automatic tube current modulation (Care Dose 4D) techniques. The information was obtained from a radiation dose monitoring software. Data were analyzed using linear correlation and analysis of variance.
Most age-wise median CTDIvol (9−27 mGy; 703/705 pediatric head CT, >99 %) from our institution were lower than the European Diagnostic Reference Levels (EDRL, CTDIvol 24−50 mGy) but median DLP (151−586 mGy cm) from 201/705 children (28 %) was higher than the EDRL (DLP 300−650 mGy cm). Unlike the age-stratified EDRL, a combination of automatic tube potential selection and tube current modulation for pediatric head results in a significant linear correlation between radiation doses and patient age (r2 = 0.66, p < 0.001).
Radiation doses for head CT change linearly with children's age. Despite lower CTDIvol and DLP for most children, longer scan length resulted in higher DLP for some pediatric head CT compared to the corresponding EDRL; this result underscores the need to promote clear guidelines for technologists operating CT.
The main purpose of this work is to estimate the acceptable quality doses (AQDs) resulting from various protocols for children undergoing CT examinations in Hamad Medical Corporation hospitals in ...Qatar.
This method has been introduced recently https://www.ncbi.nlm.nih.gov/pubmed/25430807 and it takes into account all three important parameters; image quality, dose and patient’s age. About 100 cases of pediatric patients (up to 15 y of age) have been studied for CT examination of Head, Chest and Abdomen. All Images were assessed for image quality according to scoring criteria; 1, 2, 3 and 4 corresponding to bad, not acceptable, acceptable, and higher than necessary quality, respectively. Only images with acceptable quality (score of 3) were selected and grouped into four age groups, <1, >1–5, >5–10 and >10–15 y. The median values for CTDIVol and DLP were determined as the AQD.
The initial results are shown in the table below. HeadChestAbdomenCTDIvol (mGy)DLP (mGy.cm)CTDIvol (mGy)DLP (mGy.cm)CTDIvol (mGy)DLP (mGy.cm)<1 y17.22340.6132.4108>1–5 y20.04191.5312.884>5–10 y20.75132.261312510–15 y21.84273.71096.4277
CTDIvol and DLP for CT scans of children for images of acceptable quality.
The concept of AQD allowed orientation of radiologists in image quality assessment and its documentation. Further, integration of image quality scoring with dose resulted in detection of situations with higher-than-necessary image quality and awareness and detection of opportunities for optimization.
Objective
To survey procedures and protocols in paediatric computed tomography (CT) in 40 less resourced countries.
Methods
Under a project of the International Atomic Energy Agency, 146 CT ...facilities in 40 countries of Africa, Asia, Europe and Latin America responded to an electronic survey of CT technology, exposure parameters, CT protocols and doses.
Results
Modern MDCT systems are available in 77 % of the facilities surveyed with dedicated paediatric CT protocols available in 94 %. However, protocols for some age groups were unavailable in around 50 % of the facilities surveyed. Indication-based protocols were used in 57 % of facilities. Estimates of radiation dose using CTDI or DLP from standard CT protocols demonstrated wide variation up to a factor of 100. CTDI
vol
values for the head and chest were between two and five times those for an adult at some sites. Sedation and use of shielding were frequently reported; immobilisation was not. Records of exposure factors were kept at 49 % of sites.
Conclusion
There is significant potential for improvement in CT practice and protocol use for children in less resourced countries. Dose estimates for young children varied widely. This survey provides critical baseline data for ongoing quality improvement efforts by the IAEA.
Key Points
•
Paediatric computed tomography (CT) practice was audited in 40 less resourced countries.
•
This audit revealed widespread (up to 100 times) variation in radiation dose.
•
Specific CT protocols for certain age groups were frequently (ca. 50 %) unavailable.
•
This survey demonstrates significant potential for improvement in paediatric CT practice.
•
Multinational networking is an effective mechanism for quality improvement.
PDF
