Alerts to improve occupational protection during Interventional Radiology. More attention is needed for simple but frequent procedures.

Occupational protection could be improved in interventional radiology. The monthly personal dosimetry cannot alert on some occupational doses with anomalous values for certain procedures. Active electronic personal dosimeters linked wireless to a dose management system (DMS), allow for the measurement of occupational doses per procedure, integrating this information with patient dose indicators and with technical and geometrical conditions of the procedures. We analysed around 3100 occupational dose values for individual procedures collected during the last two years, in an interventional radiology laboratory of a University Hospital and two groups, with patient doses higher than 100 Gy.cm2, and lower than 30 Gy.cm2. An unshielded reference dosimeter located at the C-arm registers the ambient dose equivalent (ADE) per procedure to be compared with the personal dose equivalent (PDE) over the apron. The ratio between both values PDE/ADE is a good indication of occupational protection. Alerts for occupational protection optimisation are suggested. For the full sample, 8.4 % of occupational doses measured over the protective apron of the interventionists were higher than 100 µSv and 3.8 % higher than 200 µSv per procedure. Occupational protection for complex procedures (>100 Gy.cm2) had median values of 46 µSv for PDE and 3.3 % for PDE/ADE. However, for simple procedures, (<30 Gy.cm2) the median values were 10 µSv and 28.4 %. This last percentage is 9 times higher than the value for complex procedures. This lack of protection should be corrected and the need to reduce some occupational doses reinforced in radiation protection training programmes for interventionists.

Occupational and patient doses for interventional radiology integrated into a dose management system.

OBJECTIVES: The International Commission on Radiological Protection recommends managing patient and occupational doses as an integrated approach, for the optimisation of interventional procedures. The conventional passive personal dosimeters only allow one to know the accumulated occupational doses during a certain period of time. This information is not enough to identify if there is a lack of occupational radiation protection during some procedures. This paper describes the use of a dose management system (DMS) allowing patient and occupational doses for individual procedures to be audited. METHODS: The DMS manages patient and occupational doses measured by electronic personal dosimeters. One dosemeter located at the C-arm is used as a reference for scatter radiation. Data have been collected from five interventional rooms. Dosimetry data can be managed for the whole procedure and the different radiation events. Optimisation is done through auditing different sets of parameters for individual procedures: patient dose indicators, occupational dose values, the ratio between occupational doses, and the doses measured by the reference dosemeter at the C-arm, and the ratio between occupational and patient dose values. RESULTS: The managed data correspond to the year 2021, with around 4500 procedures, and 8000 records on occupational exposures. Patient and staff dose data (for 11 cardiologists, 7 radiologists and 8 nurses) were available for 3043 procedures. The DMS allows alerts for patient dose indicators and occupational exposures to be set. CONCLUSIONS: The main advantage of this integrated approach is the capacity to improve radiation safety for patients and workers together, auditing alerts for individual procedures. ADVANCES IN KNOWLEDGE: The management of patient and occupational doses together (measured with electronic personal dosimeters) for individual interventional procedures, using dose management systems, allows alerting optimisation on high-dose values for patients and staff.

Dose-reducing fluoroscopic system decreases patient but not occupational radiation exposure in chronic total occlusion intervention.

AIMS: Several novel low-dose fluoroscopic systems (LDS) developed recently, but real practice information of the net benefit for the patient and professionals is scarce. We evaluated separately patient and operator radiation exposure during percutaneous interventions of chronic total occlusions (CTO). METHODS: A total of 116 consecutive CTOs were analyzed (60 in LDS and 56 in standard-dose fluoroscopic system [SDS]). Digital dosimetry of patient and occupational (operator and scatter dose) exposure was prospectively recorded. RESULTS: Biometrics, demographics, CTO variables, and operators were distributed evenly. Patient radiation exposure was effectively decreased in LDS (dose area product [DAP] by 36%, Air Kerma [AK] by 47%). However, occupational data showed no statistical differences between LDS and SDS. The LDS uses less radiation amount but with higher energy (due to additional filtration) compared to SDS, therefore increasing the scatter dose. When comparing the C-arm scatter dose to the DAP we found higher scatter dose with the LDS (0.0139 mSv/gray (Gy)*cm2 vs. 0.0082 mSv/Gy*cm2, p < .001). This was confirmed in a larger dataset comprising 5,221 coronary procedures. CONCLUSIONS: LDS was safer for patients reducing DAP and AK compared to SDS. However, occupational doses were not lower and scatter dose higher. Radiological protection measures must be kept maximized even in LDS.

Updating national diagnostic reference levels for interventional cardiology and methodological aspects.

The aim of this study is to propose national diagnostic reference levels (DRL) for updating in the field of interventional cardiology and to include technical details to help plan optimization. Medical physics experts and interventional cardiologists from 14 hospitals provided patient dose indicators from coronary angiography and percutaneous coronary interventions. Information about X-ray system dose settings and image quality was also provided. The dose values from 30,024 procedures and 26 interventional laboratories were recorded. The national DRLs proposed for coronary angiography and percutaneous coronary interventions were respectively 39 and 78 Gy·cm2 for air kerma area product (PKA), 530 and 1300 mGy for air kerma at reference point (Ka,r), 6.7 and 15 min of fluoroscopy time and 760 and 1300 cine images. 36% of the KAP meters required correction factors from 10 to 35%. The dose management systems should allow these corrections to be included automatically. The dose per image in cine in reference conditions differed in a factor of 5.5. Including X-ray system dose settings in the methodology provides an insight into the differences between hospitals. The DRLs proposed for Spain in this work were similar to those proposed in the last European survey. The poor correlation between X-ray systems dose settings and patient dose indicators highlights that other factors such as operation protocols and complexity may have more impact in patient dose indicators, which allows a wide margin for optimization. Dose reduction technology together with appropriate training programs will be determinant in the future reduction of patient dose indicators.

Experience with patient dosimetry and quality control online for diagnostic and interventional radiology using DICOM services.

OBJECTIVE: This article describes the different automatic approaches used to collect and process patient dose values and other procedural data during diagnostic and interventional radiology and discusses their benefits for clinical practice and quality control online. Approaches for automatic processing of patient dose and other procedural data for computed radiography and for flat-panel detectors extracting information from DICOM headers or via DICOM services are described. The method to perform image retake analysis is also discussed. CONCLUSION: Automatic systems to manage patient doses and procedural data are feasible and will improve radiation safety and quality in radiology. The current level of technology makes such systems achievable at a reasonable cost and with great benefit to clinical practice.

Patient dose in digital mammography.

In the present investigation, we analyze the dose of 5034 patients (20,137 images) who underwent mammographic examinations with a full-field digital mammography system. Also, we evaluate the system calibration by analyzing the exposure factors as a function of breast thickness. The information relevant to this study has been extracted from the image DICOM header and stored in a database during a 3-year period (March 2001-October 2003). Patient data included age, breast thickness, kVp, mAs, target/filter combination, and nominal dose values. Entrance surface air kerma (ESAK) without backscatter was calculated from the tube output as measured for each voltage used under clinical conditions and from the tube loading (mAs) included in the DICOM header. Mean values for the patient age and compressed breast thickness were 56 years (SD: 11) and 52 mm (SD: 13), respectively. The majority of the images was acquired using the STD (for standard) automatic mode (98%). The most frequent target/filter combination automatically selected for breast smaller than 35 mm was Mo/Mo (75%); for intermediate thicknesses between 35 and 65 mm, the combinations were Mo/Rh (54%) and Rh/Rh (38.5%); Rh/Rh was the combination selected for 91% of the cases for breasts thicker than 65 mm. A wide kVp range was observed for each target/filter combination. The most frequent values were 28 kVp for Mo/Mo, 29 kVp for Mo/Rh, and 29 and 30 kV for Rh/Rh. Exposure times ranged from 0.2 to 4.2 s with a mean value of 1.1 s. Average glandular doses (AGD) per exposure were calculated by multiplying the ESAK values by the conversion factors tabulated by Dance for women in the age groups 50 to 64 and 40 to 49. This approach is based on the dependence of breast glandularity on breast thickness and age. The total mean average glandular dose (AGD(T)) was calculated by summing the values associated with the pre-exposure and with the main exposure. Mean AGD(T) per exposure was 1.88 mGy (CI 0.01) and the mean AGD(T) per examination was 3.8 mGy, with 4 images per examination on average. The mean dose for cranio-caudal view (CC) images was 1.8 mGy, which is lower than that for medio-lateral oblique (MLO) view because the thickness for CC images was on average 10% lower than that for MLO images. Mean AGD(T) for the oldest group of women (1.90) was 3% higher than the AGD(T) for the younger group (1.85) due to the larger compressed breast thickness of women in the older group (10% on average). Differences between the corresponding AGD(T) values of each age group were lowest for breast thicknesses in the range 40-60 mm, being slightly higher for the women in the older group.