[Radiation protection in interventional radiology]

Radiation protection in CT-guided interventions: does real-time dose visualisation lead to a reduction in radiation dose to participating radiologists? A single-centre evaluation

AIM

To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists.

MATERIALS AND METHODS

The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed.

RESULTS

In total, 517 measurements of 304 interventions (n=249 with and n=268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n=280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 μSv) in the experimental group (p=0.034). The highest reduction of 78.5% (15.55 versus 3.35 μSv) was observed in radiologists with the role of assistant (p=0.002). Sub-analysis showed significant dose reduction (p<0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p=0.002).

CONCLUSION

The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists.

[Radiation protection during fluoroscopic interventions]

Facts and figures about the frequencies of fluoroscopically guided interventions (FGI), typical patient exposures and occupational exposures are listed. Limits of radiation exposure do not exist for patients but only for occupationally exposed medical personnel. Measures for radiation protection of patients and personnel are explained. Nearly all technical radiation protection measures for patients also protect the personnel. To reduce the exposure of medical personnel, radiation protection equipment should be attached to the X‑ray modality and personal radiation protection equipment should be worn. The diagnostic reference values and the obligation to report incidents, including the reporting criteria, are explained. The radiation protection of patients and personnel for FGI in Germany is well regulated by diagnostic reference values, reporting criteria, prescribed or recommended protective measures, personal dosimetry and the obligation to involve medical physics experts.

Radiation exposure during angiographic interventions in interventional radiology - risk and fate of advanced procedures

PURPOSE

Advanced angiographic procedures in interventional radiology are becoming more important and are more frequently used, especially in the treatment of several acute life-threatening diseases like stroke or aortic injury. In recent years, technical advancement has led to a broader spectrum of interventions and complex procedures with longer fluoroscopy times. This involves the risk of higher dose exposures, which, in rare cases, may cause deterministic radiation effects, e.g. erythema in patients undergoing angiographic procedures. Against this background, these procedures recently also became subject to national and international regulations regarding radiation protection. At the same time, individual risk assessment of possible stochastic radiation effects for each patient must be weighed up against the anticipated benefits of the therapy itself. Harmful effects of the administered dose are not limited to the patient but can also affect the radiologist and the medical staff. In particular, the development of cataracts in interventionalists is a rising matter of concern. Furthermore, long-term effects of repeated and prolonged x-ray exposure have long been neglected by radiologists but have come into focus in the past years.

CONCLUSIONS

With all this in mind, this review discusses different efforts to reduce radiation exposition levels for patients and medical staff by means of technical, personal as well as organizational measures.

A critical appraisal of the quality of guidelines for radiation protection in interventional radiology using the AGREE II tool: A EuroAIM initiative

PURPOSE

To systematically review and assess the methodological quality of guidelines for radiation protection in interventional radiology.

MATERIALS AND METHODS

On April 15^th, 2021, a systematic search for guidelines on radiation protection in interventional radiology was performed using MEDLINE, EMBASE, National Guideline Clearinghouse, and National Institute for Health and Clinical Excellence databases. Among retrieved guidelines, we then excluded those not primarily focused on radiation protection or on interventional radiology. Authors' professional role and year of publication were recorded for each included guideline. Guideline quality evaluation was performed independently by three authors using the six-domain tool "AGREE II", with an overall guideline quality score divided into three classes: low (<60%), acceptable (60-80%), and good quality (>80%).

RESULTS

Our literature search identified 106 citations: after applying exclusion criteria, 11 guidelines published between 2009 and 2018 were included, most of their authors being interventional radiologists (168/224, 75%). Overall quality of included guidelines was acceptable (median 72%, interquartile range 64-83%), with only one guideline (9%) with overall low quality and four guidelines (36%) with overall good quality. Among AGREE II domains, "Scope and Purpose", "Clarity of Presentations", and "Editorial Independence" had the best results (87%, 76%, and 75% respectively), while "Applicability", "Rigor of Development", and "Stakeholder Involvement" the worst (46%, 49%, and 52% respectively).

CONCLUSION

Considering all guidelines, the overall methodological quality was acceptable with one third of them reaching the highest score class. The "Applicability" domain had the lowest median score, highlighting a practical implementation gap to be addressed by future guidelines.

Effectiveness of Radiation Protection Caps for Lowering dose to the Brain and the Eye Lenses

PURPOSE

This work was designed to study the effectiveness of radiation protection caps in lowering the dose to the brain and the eye lens during fluoroscopically guided interventions.

MATERIALS AND METHODS

Two types of radiation protection caps were examined with regards to their capacity to lower the radiation dose. One cap is equipped with lateral flaps, the other one is not. These caps were fitted to the head of an anthropomorphic Alderson-Rando (A.-R.) phantom. The phantom was positioned aside an angiographic table simulating the position of the first operator during a peripheral arterial intervention. One of the brain slices and both eyes of the A.-R. phantom were equipped with thermoluminescence dosimeters (TLDs).

RESULTS

The analysis of the data showed that the cap without lateral flaps reduced the dose to the brain by 11,5-27,5 percent depending on the position within the brain. The cap with lateral protection flaps achieved a shielding effect between 44,7 and 78,9 percent. When evaluating the dose to the eye, we did see an increase of dose reduction from 63,3 to 66,5 percent in the left eye and from 45,8 to 46,8 percent in the right eye for the cap without lateral protection. When wearing the cap with lateral protection we observed an increase of dose reduction from 63,4 to 67,2 percent in the left eye and from 45,8 to 50,0 percent in the right eye.

CONCLUSION

Radiation protection caps can be an effective tool to reduce the dose to the brain and the eyes.

Effectiveness of a new radiation protection system in the interventional radiology setting

OBJECTIVES

The goal of this study was to examine a new weightless-like radiation protection garment regarding its radiation protection efficacy and to compare it to a conventional two-piece apron suit plus thyroid collar and standard ancillary shields.

MATERIAL AND METHODS

All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol for different C-arm angulations. An anthropomorphic torso phantom served as a scattering body. In addition, an ionization chamber was used to measure the radiation exposure on five different representative heights and at two different positions of an examiner during a typical fluoroscopic-guided intervention.

RESULTS

The new weightless-like radiation protection garment and the conventional protection concept showed a mean dose reduction of 98.1% (p < 0.01) and 90.1% (p < 0.01) when compared to no shielding, respectively. By adding ancillary shields to both systems, an average reduction of 99.0% (p < 0.01) and 98.2% (p < 0.01) was found. In addition, the efficacy of both systems varied depending on the height, the C-arm angulation and position of the examiner.

CONCLUSION

Combined with ancillary shields as an overall protection system, the recently introduced weightless-like radiation protection garment showed a significant better radiation protection efficacy when compared to conventional radiation protection measures.

Interventional Angiography: Radiation Protection for the Examiner by using Lead-free Gloves

INTRODUCTION

The radiation exposure to unprotected parts of the body requires special attention for the interventional radiologist. During angiographic procedures, hands are exposed to the direct X-ray beam and scattered radiation.

AIM

The aim of the study was to evaluate the radiation exposure of examiners hand with the use of lead-free X-ray protective gloves in clinical practice in terms of shielding and sense of touch. The aim of the study was to evaluate the radiation exposure of examiners hand with the use of lead-free X-ray protective gloves in clinical practice in terms of shielding and sense of touch.

MATERIALS AND METHODS

Phantom measurements were conducted in the direct X-ray beam and the area of scattered radiation with and without shielding. Examiner measurements were determined in interventional angiographies in clinical routine of the lower limb in antegrade puncture technique through the femoral artery. In 24 out of 50 interventions, an elastic natural rubber latex glove with lead-free metal shielding against radiation was used. All measurements were performed with a direct dosimeter. After the intervention, an opinion of the examiner was requested for evaluation of the sense of touch.

RESULTS

Phantom measurements; when using the protective glove in the direct X-ray beam, a significant increase of the Dose Area Product (DAP) (1084.2-1603.8 mGy*cm²; 67.6%; p<0.001) as well of the examiner's hand dose (143-221.8 μSv; 64.5%; p<0.001) was observed. A significant reduction of the examiner's hand dose was verifiable for scattered radiation (1.76-0.75 μSv; 42.6%; p<0.001). Examiner measurements; if protective gloves were used, a significant increase of the DAP (6183.2-10462.9 mGy*cm²; 59.1%; p<0.05) and decrease of the average dose rate (0.76-0.43 mSv/h; 56.6%) for the entire procedure was determined. The tactile sensitivity was assessed as not restricted (18/24).

CONCLUSION

The new generation of protective gloves is characterized by a shielding effect against X-ray scattered radiation, without restricting the sense of touch. A significant reduction in radiation doses to the examiner can be accomplished with these gloves in the area of scattered radiation only. If the gloves were used in the direct X-ray beam, especially while the artery puncture was performed, a significant increase of the dose values was observed.