Usefulness of Pelvic Radiation Protection Shields During Transfemoral Procedures-Operator and Patient Considerations

A novel robotic radiation shielding device for electrophysiologic procedures: A prospective study

BACKGROUND

A robotic Radiaction Shielding System (RSS) was developed to provide a full-body protection to all medical personnel during fluoroscopy-guided procedures, by encapsulating the imaging beam and blocking scattered radiation.

OBJECTIVES

We aimed to evaluate its efficacy in real-world electrophysiologic (EP) laboratory- both during ablations and cardiovascular implantable electronic devices (CIED) procedures.

METHODS

A prospective controlled study comparing consecutive real-life EP procedures with and without RSS using highly sensitive sensors in different locations.

RESULTS

Thirty-five ablations and 19 CIED procedures were done without RSS installed and 31 ablations and 24 CIED procedures (17 with usage levels ≥70%) were done with RSS. Overall, there was 95% average usage level for ablations and 88% for CIEDs. For all procedures with ≥70% usage level and for all sensors, the radiation with RSS was significantly lower than radiation without RSS. For ablations, there was 87% reduction in radiation with RSS (76%-97% for different sensors). For CIEDs, there was 83% reduction in radiation with RSS (59%-92%). RSS usage did not increase procedure time and radiation time. User feedback showed a high-level of integration in the clinical workflow and safety profile for all types of EP procedures.

CONCLUSIONS

For both CIED and ablation procedures the radiation with RSS was significantly lower than without RSS. Higher usage level brings higher reduction rates. Thus, RSS may have an important role in full-body protection to all medical personnel from scattered radiation during EP and CIED procedures. Until more data is available, it is recommended to maintain existing standard shielding.

Risk of ionizing radiation in pregnancy: just a myth or a real concern?

There are natural concerns regarding the risks posed to the foetus by ionizing radiation exposure during pregnancy. Therefore, many female physicians select to avoid working in an environment associated with ionizing radiation exposure like the catheterization laboratory and even exclude training as electrophysiology, interventional cardiologists, or radiologists. For those already working in this field, pregnancy involves usually a 1-year interruption (pregnancy and maternity leave) to their careers, leading at times to delays in the decision to become pregnant. This review describes the low added risk of malformation/cancer in the offspring, highlight gaps in our understanding, discuss several common wrong beliefs, and recommend how to further decrease radiation dose, especially during pregnancy.

Effect of an optimized X-ray blanket design on operator radiation dose in cardiac catheterization based on real-world angiography

Background

There is increasing concern and focus in the interventional cardiology community on potential long term health issues related to radiation exposure and heavy wearable protection. Optimized shielding measures may reduce operator dose to levels where lighter radioprotective garments can safely be used, or even omitted. X-ray blankets (XRB) are commercially available but suffer from small size and lack of stability. A larger XRB may reduce operator dose but could hamper vascular access and visualization. The aim of this study is to assess shielding effect of an optimized XRB during cardiac catheterization and estimate the potential reduction in annual operator dose based on DICOM Radiation Dose Structured Report (RDSR) data reflecting everyday clinical practice.

Methods

Data accumulated from 7681 procedures over three years in our RDSR repository was used to identify projection angles and radiation doses during cardiac catheterization. Using an anthropomorphic phantom and a scatter radiation detector, radiation dose to the operator (mSv) and patient (dose area product—DAP) was measured for each angiographic projection for three different shielding setups. Relative operator dose (mSv/DAP) was calculated and multiplied by DAP per projection to estimate effect on operator dose.

Results

Adding an optimized XRB to a standard shielding setup comprising a table- and ceiling-mounted shield resulted in a 94.9% reduction in estimated operator dose. The largest shielding effect was observed in left and cranial projections where the ceiling-mounted shield offered less protection.

Conclusions

An optimized XRB is a simple shielding measure that has the potential to reduce operator dose.

Reducing stray radiation with a novel detachable lead arm support in percutaneous coronary intervention

BACKGROUND

Placing radioprotective devices near patients reduces stray radiation during percutaneous coronary intervention (PCI), a promising technique for treating coronary artery disease. Therefore, lead arm support may effectively reduce occupational radiation dose to cardiologists.

PURPOSE

We aimed to estimate the reduction of stray radiation using a novel detachable lead arm support (DLAS) in PCI.

MATERIALS AND METHODS

A dedicated cardiovascular angiography system was equipped with the conventional 0.5-mm lead curtain suspended from the table side rail. The DLAS was developed using an L-shaped acrylic board and detachable water-resistant covers encasing the 0.5-, 0.75-, or 1.0-mm lead. The DLAS was placed adjacent to a female anthropomorphic phantom lying on the examination tabletop at the patient entrance reference point. An ionization chamber survey meter was placed 100 cm away from the isocenter to emulate the cardiologist's position. Dose reduction using the L-shaped acrylic board, DLAS, lead curtain, and their combination each was measured at five heights (80-160 cm in 20-cm increments) when acquiring cardiac images of the patient phantom with 10 gantry angulations, typical for PCI.

RESULTS

Median dose reductions of stray radiation using the L-shaped acrylic board were 9.0%, 8.8%, 12.4%, 12.3%, and 6.4% at 80-, 100-, 120-, 140-, and 160-cm heights, respectively. Dose reduction using DLAS with a 0.5-mm lead was almost identical to that using DLAS with 0.75- and 1.0-mm leads; mean dose reductions using these three DLASs increased to 16.2%, 45.1%, 66.0%, 64.2%, and 43.0%, respectively. Similarly, dose reductions using the conventional lead curtain were 95.9%, 95.5%, 83.7%, 26.0%, and 19.6%, respectively. The combination of DLAS with 0.5-mm lead and lead curtain could increase dose reductions to 96.0%, 95.8%, 93.8%, 71.1%, and 47.1%, respectively.

CONCLUSIONS

DLAS reduces stray radiation at 120-, 140-, and 160-cm heights, where the conventional lead curtain provides insufficient protection.

Effect of Different Anthropometric Body Indexes on Radiation Exposure in Patients Undergoing Cardiac Catheterisation and Percutaneous Coronary Intervention

BACKGROUND

Patient factors, such as sex and body mass index (BMI), are known to influence patient radiation exposure. Body surface area (BSA) and its association with patient radiation exposure has not been well studied.

METHODS AND RESULTS

We analysed height, weight, BMI and BSA in consecutive patients undergoing cardiac catheterisation and percutaneous coronary intervention (PCI) at a high-volume Australian centre between September 2016 and April 2020 to assess their association with dose-area product (DAP, Gycm2). The mean age of the cohort was 64.5 ± 12.3 years with males comprising 68.8% (n = 8100, 5124 diagnostic cardiac catheterisation cases and 2976 PCI cases). Median male BMI was 28.4 kg/m2 [IQR 25.2-32.1] versus 28.8 kg/m2 [24.7-33.7] for females, p = 0.01. Males had higher BSA (2.0 ± 0.2 m2) than females (1.78 ± 0.2 m2), p = 0.001. Each 0.4 m2 increase in BSA conferred a 1.32x fold change in DAP (95% CI 1.29-1.36, p ≤ 0.001). Each 5 kg/m2 increase in BMI was linked to a 1.13x DAP fold change (1.12-1.14, p ≤ 0.001). Male sex conferred a 1.23x DAP fold change (1.20-1.26, p ≤ 0.001). Multivariable modelling with BMI or BSA explained 14% of DAP variance (R2 0.67 vs. 0.53 for both, p ≤ 0.001).

CONCLUSIONS

BSA is an important anthropometric measure between the sexes and a key predictor of radiation dose and radiation exposure beyond sex, BMI, and weight.

What are useful methods to reduce occupational radiation exposure among radiological medical workers, especially for interventional radiology personnel?

Protection against occupational radiation exposure in clinical settings is important. This paper clarifies the present status of medical occupational exposure protection and possible additional safety measures. Radiation injuries, such as cataracts, have been reported in physicians and staff who perform interventional radiology (IVR), thus, it is important that they use shielding devices (e.g., lead glasses and ceiling-suspended shields). Currently, there is no single perfect radiation shield; combinations of radiation shields are required. Radiological medical workers must be appropriately educated in terms of reducing radiation exposure among both patients and staff. They also need to be aware of the various methods available for estimating/reducing patient dose and occupational exposure. When the optimizing the dose to the patient, such as eliminating a patient dose that is higher than necessary, is applied, exposure of radiological medical workers also decreases without any loss of diagnostic benefit. Thus, decreasing the patient dose also reduces occupational exposure. We propose a novel four-point policy for protecting medical staff from radiation: patient dose Optimization, Distance, Shielding, and Time (pdO-DST). Patient dose optimization means that the patient never receives a higher dose than is necessary, which also reduces the dose received by the staff. The patient dose must be optimized: shielding is critical, but it is only one component of protection from radiation used in medical procedures. Here, we review the radiation protection/reduction basics for radiological medical workers, especially for IVR staff.

Efficiency of novel shielding curtains combined with pulsed irradiation for reducing radiation exposure in an operating room: Human renal collecting system phantom study

OBJECTIVE

To evaluate the impact of novel shielding curtains combined with pulsed irradiation mode to protect medical radiation workers from radiation exposure during ureteroscopy.

METHODS

0.25 mm Pb equivalent novel shielding curtains were mounted to the caudal and bilateral sides of the operating table in the ureteroscopy setting. C-arm was positioned as per normal in the operating room with the X-ray tube under the patient table. A water-filled anthropomorphic renal collecting system phantom was positioned in the standard position on the operating table that was set at a height of 100 cm. The ionization chambers were also positioned at a height of 100 cm and set in eight positions. We took measurements at distances of 50, 100, 150, and 200 cm from the phantom with the focus directed toward the X-ray tube. We measured the spatial distribution of the scattered radiation dose in four combinations: (1) continuous irradiation mode without novel shielding curtains; (2) pulsed irradiation mode (11 films per second) without novel shielding curtains; (3) continuous irradiation mode with novel shielding curtains; and (4) pulsed irradiation mode with novel shielding curtains. Continuous or pulsed irradiation was activated for 30 s each time.

RESULTS

Pulsed irradiation mode with novel shielding curtains was a significantly more efficient method than other combinations to reduce scattered radiation exposure in this study (P < 0.001). There was approximately a 95% reduction in scattered radiation exposure with the pulsed irradiation mode with novel shielding curtains set up as compared with continuous irradiation mode without novel shielding curtains.

CONCLUSION

Combining a novel shielding curtain and using a low pulse radiation setting can greatly reduce radiation exposure during ureteroscopic procedures.

Tungsten-Based Hybrid Composite Shield for Medical Radioisotope Defense

The shielding performance of shielding clothing is typically improved by increasing the shielding material content, but this lowers the tensile strength of the material. The weight and wearability of the shielding suit are also adversely affected. Important considerations when developing shielding fabric are thickness and flexibility to allow the wearer sufficient mobility. Insufficient thickness lowers the shielding performance, whereas excessive thickness decreases the flexibility of the garment. This study aimed to develop a composite shield that reproduces the shielding performance and meets the flexibility of the process technology. The new shield was manufactured by combining two layers: the shielding fabric fabricated from tungsten wire and a shielding sheet produced by mixing a polymer (PDMS) with tungsten powder. These two shields were bonded to develop a double hybrid composite. Compared with the existing shielding sheet (produced from lead equivalent of 0.55 mmPb), the shielding performance of the hybrid composite shield improved by approximately 17% on average and the tensile strength was 53% higher. The hybrid composite shield has a thickness of 1.35 ± 0.02 mm and delivers the same shielding performance as the lead equivalent. The new hybrid composite shield offers higher wearer mobility while shielding against radiation exposure in medical institutions.

Radiation protection for the interventional cardiologist: Practical approach and innovations

Use of ionizing radiation during cardiac catheterization interventions adversely impacts both the patients and medical staff. In recent years, radiation dose in cardiac catheterization interventions has become a topic of increasing interest in interventional cardiology and there is a strong interest in reducing radiation exposure during the procedures. This review presents the current status of radiation protection in the cardiac catheterization laboratory and summarizes a practical approach for radiation dose management for minimizing radiation exposure. This review also presents recent innovations that have clinical potential for reducing radiation during cardiac interventions.

Systematic literature review on the benefit of patient protection shielding during medical X-ray imaging: Towards a discontinuation of the current practice

PURPOSE

Patient shielding during medical X-ray imaging has been increasingly criticized in the last years due to growing evidence that it often provides minimal benefit and may even compromise image quality. In Europe, and as also shown in a short assessment in Switzerland, the use of patient shielding is inhomogeneous. The aim of this study was to systematically review recent literature in order to assess benefits and appraise disadvantages related to the routine use of patient shielding.

METHODS

To evaluate benefits and disadvantages related to the application of patient shielding in radiological procedures, a systematic literature review was performed for CT, radiography, mammography and fluoroscopy-guided medical X-ray imaging. In addition, reports from medical physics societies and authorities of different countries were considered in the evaluation.

RESULTS

The literature review revealed 479 papers and reports on the topic, from which 87 qualified for closer analysis. The review considered in- and out-of-plane patient shielding as well as shielding for pregnant and pediatric patients. Dose savings and other dose and non-dose related effects of patient shielding were considered in the evaluation.

CONCLUSIONS

Although patient shielding has been used in radiological practice for many years, its use is no longer undisputed. The evaluation of the systematic literature review of recent studies and reports shows that dose savings are rather minimal while significant dose- and non-dose-related detrimental effects are present. Consequently, the routine usage of patient protection shielding in medical X-ray imaging can be safely discontinued for all modalities and patient groups.

Efficacy of MAVIG X-Ray Protective Drapes in Reducing CTO Operator Radiation

Background

The MAVIG X-ray protective drape (MXPD) has been shown to reduce operator radiation dose during percutaneous coronary interventions (PCI). Whether MXPDs are also effective in reducing operator radiation during chronic total occlusion (CTO) PCI, often with dual access, is unknown.

Methods

We performed a prospective, randomized-controlled study comparing operator radiation dose during CTO PCI (n = 60) with or without pelvic MXPDs. The primary outcomes were the difference in first operator radiation dose (μSv) and relative dose of the first operator (radiation dose normalized for dose area product) at the level of the chest in the two groups. The effectiveness of MXPD in CTO PCI was compared with non-CTO PCI using a patient-level pooled analysis with a previously published non-CTO PCI randomized study.

Results

The use of the MXPD was associated with a 37% reduction in operator dose (weighted median dose 26.0 (IQR 10.00–29.47) μSv in the drape group versus 41.8 (IQR 30.82–60.59) μSv in the no drape group; P < 0.001) and a 60% reduction in relative operator dose (median dose 3.5 (IQR 2.5–5.4) E/DAPx10⁻³ in the drape group versus 8.6 (IQR 4.2–12.5) E/DAPx10⁻³ in the no drape group; P=0.001). MXPD was equally effective in reducing operator dose in CTO PCI compared with non-CTO PCI (P value for interaction 0.963).

Conclusions

The pelvic MAVIG X-ray protective drape significantly reduced CTO operator radiation dose. This trial is clinically registered with https://www.clinicaltrials.gov (unique identifier: NCT04285944).

Personalized Radiation Attenuating Materials for Gastrointestinal Mucosal Protection

Cancer patients undergoing therapeutic radiation routinely develop injury of the adjacent gastrointestinal (GI) tract mucosa due to treatment. To reduce radiation dose to critical GI structures including the rectum and oral mucosa, 3D-printed GI radioprotective devices composed of high-Z materials are generated from patient CT scans. In a radiation proctitis rat model, a significant reduction in crypt injury is demonstrated with the device compared to without (p < 0.0087). Optimal device placement for radiation attenuation is further confirmed in a swine model. Dosimetric modeling in oral cavity cancer patients demonstrates a 30% radiation dose reduction to the normal buccal mucosa and a 15.2% dose reduction in the rectum for prostate cancer patients with the radioprotectant material in place compared to without. Finally, it is found that the rectal radioprotectant device is more cost-effective compared to a hydrogel rectal spacer. Taken together, these data suggest that personalized radioprotectant devices may be used to reduce GI tissue injury in cancer patients undergoing therapeutic radiation.

Safety and effectiveness of strategies to reduce radiation exposure to proceduralists performing cardiac catheterization procedures: a systematic review

OBJECTIVE

The objective of this systematic review was to synthesize the best available evidence on the effect of various radiation protection strategies on radiation dose received by proceduralists performing cardiac catheterization procedures involving fluoroscopy.

INTRODUCTION

Cardiac catheterization procedures under fluoroscopy are the gold standard diagnostic and treatment method for patients with coronary artery disease. The growing demand of procedures means that proceduralists are being exposed to increasing amounts of radiation, resulting in an increased risk of deterministic and stochastic effects. Standard protective strategies and equipment such as lead garments reduce radiation exposure; however, the evidence surrounding additional equipment is contradictory.

INCLUSION CRITERIA

Randomized controlled trials that compared the use of an additional radiation protection strategy with conventional radiation protection methods were considered for inclusion. The primary outcome of interest was the radiation dose received by the proceduralist during cardiac catheterization procedures.

METHODS

A three-step search was conducted in MEDLINE, CINAHL, Embase, and the Cochrane Library (CENTRAL). Trials published in the English language with adult participants were included. Trials published from database inception until July 2019 were eligible for inclusion. The methodological quality of the included studies was assessed using the JBI critical appraisal checklist for randomized controlled trials. Quantitative data were extracted from the included papers using the JBI data extraction tool. Results that could not be pooled in meta-analysis were reported in a narrative form.

RESULTS

Fifteen randomized controlled trials were included in the review. Six radiation protection strategies were assessed: leaded and unleaded pelvic or arm drapes, transradial protection board, remotely controlled mechanical contrast injector, extension tubing for contrast injection, real-time radiation monitor, and a reduction in frame rate to 7.5 frames per second. Pooled data from two trials demonstrated a statistically significant decrease in the mean radiation dose (P < 0.00001) received by proceduralists performing transfemoral cardiac catheterization on patients who received a leaded pelvic drape compared to standard protection. One trial that compared the use of unleaded pelvic drapes placed on patients compared to standard protection reported a statistically significant decrease (P = 0.004) in the mean radiation dose received by proceduralists.Compared to standard protection, two trials that used unleaded arm drapes for patients, one trial that used a remotely controlled mechanical contrast injector, and one trial that used a transradial protection board demonstrated a statistically significant reduction in the radiation dose received by proceduralists.Similarly, using a frame rate of 7.5 versus 15 frames per second and monitoring radiation dose in real-time radiation significantly lowered the radiation dose received by the proceduralist. One trial demonstrated no statistically significant difference in proceduralist radiation dose among those who used the extension tubing compared to standard protection (P = 1).

CONCLUSIONS

This review provides evidence to support the use of leaded pelvic drapes for patients as an additional radiation protection strategy for proceduralists performing transradial or transfemoral cardiac catheterization. Further studies on the effectiveness of using a lower fluoroscopy frame rate, real-time radiation monitor, and transradial protection board are needed.

The radioprotective effect of the Cathpax® AIR cabin during interventional cardiology procedures

BACKGROUND

The use of ionizing radiation during cardiac catheterization interventions adversely impacts the medical staff. Traditional radiation protection equipment is only partially effective. The Cathpax® radiation protection cabin (RPC) has proven to significantly reduce radiation exposure in electrophysiological and neuroradiology interventions. Our objective was to analyze whether the Cathpax® RPC reduces radiation dose in coronary and cardiac structural interventions in unselected real-world procedures.

METHODS AND RESULTS

In this nonrandomized all-comers prospective study, 119 consecutive cardiac interventional procedures were alternatively divided into two groups: the RPC group (n = 59) and the non-RPC group (n = 60). No significant changes in the characteristics of patients and procedures, average contrast volume, air kerma (AK), dose area-product (DAP) and fluoroscopy time between both groups were apparent. In the RPC group, the first-operator relative radiation exposure was reduced by 78% at the chest and by 70% at the wrist. This effect was consistent during different types of procedures including complex percutaneous interventions and structural procedures.

CONCLUSIONS

Our study demonstrates, for the first time, that the Cathpax® cabin significantly and efficiently reduces relative operator radiation exposure during different types of interventional procedures, confirming its feasibility in a real-world setting.

THE EFFICACY OF RADPAD AS A RADIATION PROTECTION TOOL IN CT FLUOROSCOPY GUIDED LUNG BIOPSIES

Computed tomography fluoroscopy is now the preferred technique for percutaneous lung biopsies. However, concern regarding operator and patient radiation dose remains, which warrants further exploration into dose optimisation tools. This phantom-study aims to assess the dose reduction capabilities of RADPAD, a single-use patient drape designed to decrease staff exposure to scattered radiation. Dosemeters at the waist and eye levels were used to determine the whole-body and lens exposure during simulated lung biopsy procedures while using RADPAD and other combinations of personal protective equipment. RADPAD resulted in a 36% and 38% dose reduction for whole-body and eye exposure, respectively. However, when used in combination with radioprotective eyewear and aprons, RADPAD did not reduce the radiation dose further. Consequently, the use of standard personal protective equipment is a more cost-effective option for staff dose reduction. RADPAD is useful in the reduction of radiation dose to unprotected regions.

Efficacy of MAVIG X-Ray Protective Drapes in Reducing Operator Radiation Dose in the Cardiac Catheterization Laboratory: A Randomized Controlled Trial

BACKGROUND

Interventional cardiologists are occupationally exposed to high doses of ionizing radiation. The MAVIG X-ray protective drape (MXPD) is a commercially available light weight, lead-free shield placed over the pelvic area of patients to minimize operator radiation dose. The aim of this study was to examine the efficacy of the MXPD during routine cardiac catheterization, including percutaneous coronary interventions.

METHODS

We performed a prospective, randomized controlled study comparing operator radiation dose during cardiac catheterization and percutaneous coronary intervention (n=632) with or without pelvic MXPD. We measured operator radiation dose at 4 sites: left eye, chest, left ring finger, and right ring finger. The primary outcomes were the difference in first operator radiation dose (µSv) and relative dose of the first operator (radiation dose normalized for dose area product) at the level of the chest in the 2 groups.

RESULTS

The use of the MXPD was associated with a 50% reduction in operator radiation dose (median dose 30.5 [interquartile range, 23.0-39.7] µSv in no drape group versus 15.3 [interquartile range, 11.1-20.0] µSv in the drape group; P<0.001) and a 57% reduction in relative operator dose (P<0.001). The largest absolute reduction in dose was observed at the left finger (median left finger dose for the no drape group was 104.9 [75.7-137.4] µSv versus 41.9 [32.6-70.6] µSv in the drape group; P<0.001).

CONCLUSIONS

The pelvic MXPD significantly reduces first operator radiation dose during routine cardiac catheterization and percutaneous coronary intervention. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT04285944.