Radiation exposure to anaesthetists during endovascular procedures

Assessment of the Occupational Radiation Exposure of Anesthesia Staff in Interventional Cardiology

Introduction

This research seeks to evaluate the occupational radiation dose, quantified as the whole-body Annual Mean Effective Dose (AMED), received by anesthesia personnel in interventional cardiology.

Methods

Thermoluminescent dosimetry data was collected over five years (2019-2023) for a total of 175 anesthesia staff. Technologists comprised approximately 72.4% of the participants (55% male and 45% female), while consultants accounted for 27.6% (70% male and 30% female). Statistical tests, including Independent Samples T-Test and One-Way ANOVA, compared AMED across genders, job titles, and years.

Results

The study's findings on AMED across all staff from 2019 to 2023 showed marked variability in AMED. There was a significant rise in AMED from 0.72 mSv in 2019 to 0.92 mSv in 2020, then a decline to 0.82 mSv in 2021, with further decreases to 0.67 mSv in 2022 and finally to 0.65 mSv in 2023 (p < 0.001). The average AMED over the five-year span (2019-2023) was 0.76 ± 0.4 mSv. In terms of gender, the overall AMED for males was 0.73 ± 0.36 mSv and for females 0.79 ± 0.45 mSv, showing no significant statistical difference (p = 0.272). Significant differences in exposure were observed between the technologists who experienced a higher overall AMED (0.8 ± 0.43 mSv) compared to consultants (0.63 ± 0.29 mSv, p = 0.008).

Discussion

Despite these variations, AMED values remained lower than the annual occupational dose limit of 20 mSv, indicating generally low radiation exposure for anesthesia staff. This study emphasizes the importance of ongoing monitoring and enhanced protective measures to safeguard the health of medical professionals working with radiation.

Estimation of occupational radiation doses in neuroendovascular procedures

To estimate the mean effective dose per procedure with multiple dosimetry, to calculate the annual effective dose to personnel working in neuroendovascular procedures and compared with methods reported in the literature and with national and international limits. The radiation dose to personnel was monitored in 20 procedures classified as diagnostic or therapeutic. During each procedure, the equivalent dose to eyes, thyroid, under and over the lead apron at chest level, hands, gonads and knees was measured with lithium fluoride thermoluminescent dosimeter chips (TLD-100). Estimations of the annual effective dose from different methods found in literature that use one or two dosimeters and from this work were compared. Also, a comparison was made with the safety limits recommended in national and international regulations. Radiation exposure to eyes, thyroid, gonads and knees is relevant to the effective dose, and therefore to the annual effective dose estimations. Personnel position is important, as the performing physician, who is closer to the patient, received the highest dose measured. In particular, this was observed in the equivalent dose received over the apron. However, the equivalent dose to the right eye was higher for neuroanaesthesiologists than for performing physicians due to their position relative to the patient. In general, effective doses estimated using one- and two-dosimeter methods found in the literature were, respectively, lower and higher than those obtained with the ten-dosimeter method in this work. The annual effective doses to personnel estimated with the multiple dosimetry algorithm ranged from 1.3 to 1.5 mSv y^-1and are within the national and international limits.

Effectiveness of a radiation protective device for anesthesiologists and transesophageal echocardiography operators in structural heart disease interventions

In structural heart disease (SHD) interventions, the exposure of staff other than the first operator such as anesthesiologists and transesophageal echocardiography (TEE) operators to the radiation can also pose the risks of cancer and cataracts in the long term. This study was conducted to test our new radiation protective device (RPD) for anesthesiologists and TEE operators in SHD interventions. The RPD, which consists of a head side shield and a cradle shield, was mounted on a 0.25 mm Pb-equivalent unleaded radiation protection sheet on a self-made J-shaped acrylic table, and it was placed on the head side and cradle on the operating table. A CT human body phantom was placed on the operating table, and the C-arm was set in five directions: posteroanterior, right anterior oblique 30°, left anterior oblique 30°, caudal 30°, and cranial 30°. The ambient dose equivalent rate at the usual positions of the anesthesiologist and TEE operator were measured under a fluoroscopic sequence with and without the RPD, and the dose reduction rate was obtained. The height of each measurement point was set to 100, 130 or 160 cm. The reduction rates at the positions of the anesthesiologist and the TEE operator were 82.6-86.4% and 77.9-89.5% at the height of 100 cm, 48.5-68.4% and 83.3-91.0% at 130 cm, and 23.6-62.9% and 72.9-86.1% at 160 cm, respectively. The newly developed RPD can thus effectively reduce the radiation exposure of anesthesiologists and TEE operators during SHD interventions.

Editor's Choice - Comprehensive Literature Review of Radiation Levels During Endovascular Aortic Repair in Cathlabs and Operating Theatres

OBJECTIVE

Occupational exposure is a growing concern among the endovascular specialist community. Several types of imaging equipment are available, such as mobile C arms or hybrid rooms, and some have been shown to deliver higher levels of radiation. A literature review was conducted to identify studies reporting dose data during standard (EVAR) and complex abdominal aortic endovascular repair (fenestrated/branched EVAR [F/BEVAR]).

METHODS

A search of the MEDLINE and the Cochrane databases was performed by two independent investigators using the medical subject heading terms "aortic aneurysms", "radiation", and "humans" over a search period of 10 years. Studies with full text available in English and reporting radiation data independently from the imaging equipment type were included. Experimental studies were excluded.

RESULTS

The lowest dose-area product levels during EVAR and F/BEVAR were identified in hybrid rooms, while the highest were with fixed systems. When adherence to the as low as reasonably achievable principles was stipulated by the authors, dose reports tended to be among the lowest. Several studies, especially of F/BEVAR, report concerning levels of radiation for both patients and staff.

CONCLUSION

Modern imaging equipment type, team involvement with radiation management, and the support of recent imaging technologies such as fusion help to reduce the dose delivered during standard and complex EVAR. Investment in modern imaging technology should be considered in every centre providing endovascular management of aortic aneurysms.

Radiation Exposure of Anaesthetists Visualised by Real-time Dosimetry

BACKGROUND

Chronic exposure to occupational ionising radiation is seen as one reason for elevated cancer prevalence.

OBJECTIVE

The aim of this retrospective study was to evaluate radiation exposure of anaesthetists by real-time dosimetry.

METHODS

Data of 296 patients were analyzed. Ten types of trauma operation procedures including osteosynthesis of upper and lower extremity fractures and minimally invasive stabilisation of traumatic and osteoporotic vertebral fractures were accomplished. Evaluation was performed by an occupational dosimetry system, which visualises anaesthetists radiation exposure feedback compared to surgeons in real-time.

RESULTS

A significantly lower radiation exposure to anaesthetists compared to surgeons was observed in four types of operative procedures: Plate fixation of proximal humerus fractures, osteosynthesis of proximal femoral fractures, stabilisation of traumatic and osteoporotic vertebral fractures. In four types of operations (plate osteosynthesis of proximal humeral, distal radial and tibial fractures and intramedullary nailing of the clavicle), anaesthetists` amount of radiation exceeded one-third of the surgeons' exposure, especially if the C-arm tube was positioned close to the anaesthetists work station at the patients' head.

CONCLUSION

By using the occupational radiation dose monitoring system, radiation exposure to anaesthetists was visualised in real-time during trauma operations. Radiation exposure of anaesthetists depends on the type of operation and the position of the C-arm. The system may help to increase anaesthetists` awareness concerning radiation exposure and to enhance compliance in using radiation protection techniques.

The Patient Size Setting: A Novel Dose Reduction Strategy in Cerebral Endovascular Neurosurgery Using Biplane Fluoroscopy

BACKGROUND

In some fluoroscopy machines, the dose-rate output of the fluoroscope is tied to a selectable patient size. Although patient size may play a significant role in visceral or cardiac procedures, head morphology is less variable, and high dose outputs may not be necessary even in very obese patients. We hypothesized that very small patient size setting can be used to reduce dose for cerebral angiography without compromising image quality.

METHODS

Patients who underwent endovascular neurosurgical procedures during the 2015-2016 academic year were identified, and estimated procedural air kerma (AK) was tabulated retrospectively. Technologists were instructed to begin using the very small patient size setting for all procedures performed using our Philips Allura Xper FD20 biplane fluoroscopy system beginning in March 2016. No changes were made in a second procedure room using a Toshiba Infinix system. Student t tests and logistic regression models were used to compare radiation exposure before and after March 1, 2016, for both machines.

RESULTS

For diagnostic cerebral angiograms performed on the Philips system (n = 302), AK was reduced by approximately 17% (1277 vs. 1061 mGy; P = 0.0006.) Changes in table height, total fluoroscopy time, patient weight, and body mass index did not contribute to this difference. No significant change was seen in total AK using the Toshiba system (n = 237). Blinded review by a neuroradiologist did not demonstrate any change in image quality.

CONCLUSIONS

Using the very small patient size reduces fluoroscopy dose by 17% for cerebral angiography without impacting image quality.

Meta-analysis of Cumulative Radiation Duration and Dose During EVAR Using Mobile, Fixed, or Fixed/3D Fusion C-Arms

Purpose: To investigate the total fluoroscopy time and radiation exposure dose during endovascular aortic repairs using mobile, fixed, or fixed C-arms with 3-dimensional image fusion (3D-IF). Methods: A systematic search was performed to identify original articles reporting fluoroscopy time (FT) and the kerma area product (KAP) during endovascular aortic repairs. Data were grouped by noncomplex or complex (fenestrated, branched, or chimney) repairs and stratified by type of C-arm. The search identified 27 articles containing 51 study groups (35 noncomplex and 16 complex) that included 3444 patients. Random-effects meta-analysis and meta-regression models were used to calculate the pooled mean estimates of KAP and FT, as well as any effect of equipment or type of intervention. Results are presented with the 95% confidence interval and the statistical heterogeneity ( I2). Results: Within the noncomplex procedure studies, a significant (p<0.001) increase was found in the pooled mean KAP estimate in the fixed C-arm group (181 Gy·cm2, 95% CI 129 to 233; I2=99.7) compared with the mobile C-arm (78 Gy·cm2, 95% CI 59.6 to 97.3; I2=99.6). For complex cases, use of 3D-IF showed a significantly (p<0.001) lower mean KAP (139 Gy·cm2, 95% CI 85 to 191; I2=94%) compared to using fixed C-arms without 3D-IF (487 Gy·cm2, 95% CI 331 to 643; I2=94%). Conclusion: For equivalent fluoroscopy times, the use of a fixed C-arm in noncomplex procedures leads to higher patient radiation doses compared to a mobile C-arm. Complex procedures, which are predominantly performed using fixed C-arms, are associated with the highest radiation dose per intervention. Using fixed C-arms combined with 3D-IF techniques during complex cases might seem an adequate method to compensate for the higher radiation doses measured when a fixed C-arm is used.