Randomized Controlled Trial on the Reduction of Scattered Radiation Exposure to Primary Operator, Secondary Operator, and Primary Technician by Radiation Protection Drape in Cath Lab Procedures

Abstract

Background

Scattered radiation during cath laboratory procedures poses occupational risks to medical staff, including primary operators, secondary operators, and technicians. It is associated with DNA damage, cataracts, and other complications. Although radiation protection drapes are recommended, their effectiveness across different personnel requires further evaluation.

Objective

This study assessed the efficacy of radiation protection drapes in reducing scattered radiation exposure for cath laboratory staff.

Materials and Methods

A single-center, open-label, parallel-group randomized controlled trial included 216 patients undergoing cath laboratory procedures. Patients were randomized into two groups: one with radiation protection drapes and another with standard radiation protection. Personnel exposure was measured via personal dosimeters attached to chest pockets, evaluating air kerma (AK), dose area product (DAP), and cine-adjusted screen time (CAST).

Results

Radiation protection drapes significantly reduced exposure across all personnel during femoral and radial procedures. Primary operators saw reductions of 63.65% (dose/AK), 51.94% (dose/DAP), and 44.27% (dose/CAST). Secondary operators experienced reductions of 46.54, 36.42, and 35.93%, while technicians recorded reductions of 44.51, 34.26, and 35.61%, respectively. In pectoral procedures, primary and secondary operators benefited, with exposure reductions of up to 62% (dose/AK), 49% (dose/DAP), and 52% (dose/CAST), while no significant reduction was observed for technicians.

Conclusion

Radiation protection drapes effectively reduced scattered radiation exposure for primary and secondary operators, with primary operators benefiting the most.

Keywords

scattered radiation - radiation protection drapes - cath laboratory procedures - randomized controlled trial - occupational exposure

Introduction

The introduction of ionizing radiation in medicine has revolutionized disease diagnosis and treatment, particularly in interventional cardiology, where fluoroscopy-guided procedures are essential for managing cardiovascular diseases.[1] These procedures have greatly enhanced patient care by allowing for more accurate and minimally invasive interventions. However, they also expose healthcare providers and patients to radiation risks, including both deterministic and stochastic effects.[2]

Healthcare personnel in cath laboratories, particularly interventional cardiologists, face higher incidences of radiation-induced health issues such as somatic DNA damage, chromosomal abnormalities, and posterior sub-capsular lens opacities. Notably, disproportionate radiation exposure on the left side of the head has been linked to an elevated risk of cataracts among cath laboratory workers.[3] [4] [5] Even anesthesiologists in cath laboratories experience greater radiation exposure compared with those in operating rooms.[6] Several factors influence radiation exposure in the cath laboratory, including the complexity and length of procedures, patient-specific characteristics, the availability of protective equipment, and the operator's level of experience.[7]

The growing awareness of these risks has led to a stronger emphasis on the “as low as reasonably achievable” (ALARA) principle, which focuses on minimizing radiation exposure while maintaining diagnostic accuracy. Efforts to reduce radiation exposure in the cath laboratory are critical not only for patient safety but also for safeguarding the health of medical personnel.[8] Radiation protection strategies encompass both passive and active elements. Passive components include protective equipment such as radiation protection aprons, thyroid protection collars, glasses, caps, and supplementary devices like mobile acrylic shields and under-table lead curtains. Active processes rely on the effective utilization of these tools.[9] [10] Among these, radiation protection drapes, made from sterile surgical material embedded with radiation-absorbing elements such as bismuth and barium, serve as a crucial barrier against scattered radiation. Positioned strategically between the image intensifier and the operator, these drapes significantly mitigate radiation dispersion.[11]

Despite the availability of radiation protection devices, there is limited literature comparing exposure levels among cath laboratory personnel and evaluating the efficacy of radiation protection drapes in reducing exposure. Moreover, previous studies have reported inconsistent results regarding their effectiveness. This study aims to address these gaps by systematically assessing the role of radiation protection drapes in reducing radiation exposure to primary operators, secondary operators, and technicians during cath laboratory procedures.

Materials and Methods

Study Objectives

This study aimed to assess the relative radiation exposure experienced by different cath laboratory personnel (primary operator, secondary operator, and technician) and evaluate the efficacy of radiation protection drapes in reducing exposure, thereby preventing occupational hazards in interventional cardiology settings.

Study Design

This was a single-center, parallel, open-label randomized controlled trial (RCT) with a 1:1 allocation ratio. The trial was conducted over 18 months, from November 2022 to April 2024, to evaluate the effectiveness of radiation protection drapes in reducing scattered radiation exposure during cardiac catheterization procedures.

Study Participants

Participants included adults aged 18 years or older undergoing catheterization procedures at the study center. Inclusion criteria included patients weighing more than 50 kg. Patients undergoing hybrid therapies or procedures involving multiple sites were excluded. Other exclusion criteria included procedures with multiple primary operators, those lacking a secondary operator, or cases where the secondary operator or technician was changed midway through the procedure. Patients with incomplete procedures for any reason were also excluded.

The study adhered to institutional protocols for radiation protection, including the use of standard personal protective equipment (PPE) such as lead aprons and thyroid shields. Additionally, a ceiling-suspended radiation shield was employed to minimize scatter radiation exposure to operators.

Sample Size Calculation and Randomization

The sample size was calculated based on a prior study by Shah et al[12] with a 95% confidence interval and 80% power; the minimum required sample size was determined to be 28 participants per group. Adjusting for a 10% error rate, the target sample size was increased to 33 participants per group. However, enrolment was extended until 216 patients (108 in each group) were included to ensure robust analysis within the study's timeframe.

Patients meeting the inclusion and exclusion criteria were randomized into two groups: the intervention group (radiation protection drape) and the control group (standard radiation protection measures without drape) using a computer-based algorithm that assigned participants unique identifiers to ensure unbiased allocation. The randomization process employed a pseudorandom number generator, providing equal chances of assignment to either the intervention or control group. The allocation flow is depicted in [Fig. 1].

Fig. 1 Study workflow.

Interventions

The intervention group used a radiopaque bismuth radiation protection drape (RADPAD) to attenuate scattered radiation. The drape was positioned strategically depending on the vascular access route. For radial artery access, the drape was placed craniomedially on the patient's forearm near the sheath insertion point. For femoral artery access, it was placed cranially on the groin above the insertion site. In pectoral access procedures, the drape was positioned between the incision site and the operator on the patient's left side. In the control group, standard radiation protection protocols were followed without the use of a radiation protection drape.

Outcome Measures

Radiation exposure was quantified using personal dosimeters (MYDOSE mini PDM127, Hitachi Aloka Medical Ltd., Japan), which were clipped to the chest pockets of the cath laboratory personnel and remained in place for the entire procedure. Radiation parameters recorded included air kerma (AK), dose area product (DAP), and cine-adjusted screen time (CAST). CAST was calculated by multiplying the number of cine acquisitions by 15 (average cine emits 15 times more radiation than fluoroscopy) and then by 4 (average cine duration in seconds). These parameters were used to compare radiation exposure among primary operators, secondary operators, and technicians in both groups.

Statistical Analysis

All statistical analyses were performed using SPSS v.21 (IBM, Chicago, Illinois). Continuous variables were presented as mean ± standard deviation (SD) or as medians if data were unevenly distributed, while categorical variables were expressed as frequencies and percentages. A paired Student's t-test was used to compare continuous variables between the groups, and one-way ANOVA was utilized for comparisons across groups. For non-normally distributed variables, the Mann-Whitney U test was applied. A p-value of <0.05 was considered statistically significant.

Ethical Considerations

Approval for the study was obtained from the Institutional Ethics Committee, and the trial was registered with the Clinical Trials Registry of India (CTRI/2022/11/047008). All participants provided informed consent.

Results

A total of 216 patients were included in this study between November 2022 and April 2024. Participants were randomized in a 1:1 ratio into two groups: one group receiving the radiation protection drape and the other following standard protocols without the drape, with 108 patients in each group. [Table 1] summarizes the demographic characteristics of the patients, including sex, age, weight, and distribution of vascular access. The most performed procedure was percutaneous transluminal coronary angioplasty (PTCA) (51.3%), followed by dual-chamber pacemaker implantation (DDDR) (23%), as depicted in [Fig. 2].

Table 1 Baseline demographic characteristics of the patients in the two groups

Parameters	Radiation protection drape	No radiation protection drape	Total
Gender
Male, N (%)	81 (75%)	75 (70%)	156 (72%)
Female, N (%)	27 (25%)	33 (30%)	60 (28%)
Vascular access
Radial, N (%)	42 (38%)	36 (33%)	78 (36%)
Femoral, N (%)	30 (28%)	36 (33%)	66 (31%)
Pectoral, N (%)	36 (33%)	36 (33%)	72 (33%)
Age (years) Mean ± SD	61.2 ± 11.03	56.24 ± 14.77
Weight (kg) Mean ± SD	62.76 ± 7.69	63.53 ± 8.72

Fig. 2 Distribution of different procedures in this study. CAD, coronary artery disease; CRT, cardiac resynchronization therapy; DDDR, dual-chamber, rate-responsive pacemaker, ICD, implantable cardioverter-defibrillator; PAG, percutaneous aortogram or pacemaker atrial lead guidance; PTCA, percutaneous transluminal coronary angioplasty; PTMC, percutaneous transvenous mitral commissurotomy; VVIR, ventricular demand pacing with rate response.

Radiation Exposure in Radial and Femoral Procedures

For primary operators (PO), the mean radiation dose was 21.88 µSv in the drape group compared with 47.38 µSv in the control group, reflecting a numerical reduction. Although this difference was not statistically significant, adjustments for AK, DAP, and CAST yielded statistically significant reductions (p < 0.05; [Fig. 3]). Similarly, for secondary operators (SO), the mean dose was reduced from 12.41 µSv in the control group to 8.98 µSv in the drape group. Although the numerical reduction did not reach statistical significance, the adjusted results for AK, DAP, and CAST showed significant reductions (p < 0.05; [Fig. 4]). For technicians, the mean radiation dose decreased from 3.12 µSv in the control group to 2.41 µSv in the drape group. Despite low absolute exposure levels, the adjusted results demonstrated statistical significance (p < 0.05; [Fig. 5]).

Fig. 3 Comparison of radiation parameters in primary operator (PO) with and without the use of radiation protection drape for all radial/femoral procedures showing percentage reduction with use of radiation protection drape. AK, air kerma; CAST, cine-adjusted screen time; DAP, dose area product.

Fig. 4 Comparison of radiation parameters in secondary operator (SO) with and without the use of radiation protection drape for all radial/femoral procedures showing percentage reduction with use of radiation protection drape. AK, air kerma; CAST, cine-adjusted screen time; DAP, dose area product.

Fig. 5 Comparison of radiation parameters in technicians with and without the use of radiation protection drape for all radial/femoral procedures showing percentage reduction with use of radiation protection drape. AK, air kerma; CAST, cine-adjusted screen time; DAP, dose area product.

Radiation Exposure in Pectoral Procedures

For primary operators, the mean radiation dose was significantly reduced from 96.75 µSv in the control group to 62.86 µSv in the drape group. Adjustments for AK, DAP, and CAST further confirmed the statistical significance of these reductions (p < 0.05; [Fig. 6]). Secondary operators experienced a reduction in mean dose from 34.22 µSv (control) to 23.50 µSv (drape), with adjusted parameters showing significant reductions (p < 0.05; [Fig. 7]). However, for technicians, the mean dose was slightly higher in the drape group (3.36 µSv) compared with the control group (2.80 µSv). Adjustments for AK, DAP, and CAST revealed no statistically significant differences between the groups ([Table 2]).

Table 2 Comparison of radiation parameters in technicians with and without the use of radiation protection drape for all pectoral procedures showing percentage change with use of radiation protection drape

Patient group	Tech—Dose/AK, µSv/mgy	Tech—Dose/DAP, µSv/mgycm[2]	Tech—Dose/CAST, µSv/min
Control group	0.01	0.01	0.104
Intervention group	0.01	0.01	0.101
Reduction	−2%	−2%	3%

Abbreviations: AK, air kerma; CAST, cine-adjusted screen time; DAP, dose area product.

Fig. 6 Comparison of radiation parameters in primary operators with and without the use of radiation protection drape for all pectoral procedures showing percentage reduction with use of radiation protection drape. AK, air kerma; CAST, cine-adjusted screen time; DAP, dose area product.

Fig. 7 Comparison of radiation parameters in secondary operator with and without the use of radiation protection drape for all pectoral procedures showing percentage reduction with use of radiation protection drape. AK, air kerma; CAST, cine-adjusted screen time; DAP, dose area product.

Comparative Analysis of Radiation Exposure

Across all procedures, the primary operators received the highest radiation exposure, followed by secondary operators, with technicians receiving the least. In radial and femoral procedures, the primary operator's exposure was consistently higher than that of secondary operators and technicians, as outlined in [Table 3]. The percentage differences in radiation exposure between groups, both with and without the radiation drape, are detailed in [Table 4]. Similarly, in pectoral procedures, the highest exposure was recorded for primary operators, followed by secondary operators and technicians, as summarized in [Table 5]. The percentage reductions in exposure for each group in the presence and absence of the drape are presented in [Table 6].

Table 3 Comparison of the radiation exposure among the primary operator, secondary operator, and technician in radial/femoral procedures

	PO dose (µSv)	SO dose (µSv)	Tech dose (µSv)
Intervention group	21.88	8.98	2.25
Control group	47.38	12.41	3.12

Abbreviations: PO, primary operator; SO, secondary operator; Tech, technician.

Table 4 Comparison of the relative radiation exposure among the primary operator, secondary operator, and technician in radial/femoral procedures by percentages with and without radiation protection drape

	Intervention group
PO vs. SO dose	59%	Higher
PO vs. Tech dose	90%	Higher
SO vs. Tech dose	75%	Higher
	Control group
PO vs. SO dose	74%	Higher
PO vs. Tech dose	93%	Higher
SO vs. Tech dose	75%	Higher

Abbreviations: PO, primary operator; SO, secondary operator; Tech, technician.

Table 5 Comparison of the radiation exposure among the primary operator, secondary operator, and technician in pectoral procedures

	PO dose (µSv)	SO dose (µSv)	Tech dose (µSv)
Intervention group	62.86	23.53	3.36
Control group	96.75	34.28	2.81

Abbreviations: PO, primary operator; SO, secondary operator; Tech, technician.

Table 6 Comparison of the relative radiation exposure among the primary operator, secondary operator, and technician in pectoral procedures by percentages with radiation protection drape

	Intervention group
PO vs. SO dose	63%	Higher
PO vs. Tech dose	95%	Higher
SO vs. Tech dose	86%	Higher
	Control group
PO vs. SO dose	65%	Higher
PO vs. Tech dose	97%	Higher
SO vs. Tech dose	92%	Higher

Abbreviations: PO, primary operator; SO, secondary operator; Tech, technician.

Discussion

Radiation protection in cath laboratories is paramount to mitigating the health risks associated with ionizing radiation. Although strategies such as the ALARA principle, personal protective equipment, and education in radiation safety are well-established,[8] [13] limited literature specifically addresses the exposure levels and associated risks for secondary operators and technicians. This study aimed to fill this gap by evaluating the efficacy of radiation protection drapes, such as RADPAD, in reducing exposure for all personnel categories.

The findings of this study show that radiation protection drapes effectively reduce exposure for primary and secondary operators in both radial/femoral and pectoral procedures. These results align with prior studies showing significant reductions in radiation exposure with the use of RADPAD during interventional procedures.[14] [15] In the RECAP trial, use of the RADPAD reduced operator exposure by 20% compared with standard protection and by 44% compared with a sham shield, with consistent benefits across subgroups such as obese patients and PCI cases. Notably, procedures performed with the sham shield alone resulted in higher operator exposure than standard practice, due to a false sense of security. These findings emphasize that the protective effect is not merely behavioral but directly attributable to the material properties of the drape.[16] A recent comparative study by Cammann et al further supports these findings by demonstrating the effectiveness of radiation protection systems, including RADPAD, in minimizing operator exposure during cardiac catheterization.[14] For technicians, the reductions were significant in radial and femoral procedures but not in pectoral procedures, consistent with prior studies that observed variable effectiveness depending on procedural type and operator position.[17] This discrepancy may be attributed to technicians' relative positioning during procedures, where the drape's protective effect is less pronounced.

When compared with earlier studies, such as the MILD study,[17] the reductions observed in this study are consistent with previously reported ranges. However, the study highlights the need for further exploration into strategies to enhance protection for technicians, especially during pectoral procedures, where exposure reductions remain limited. Importantly, evidence from outside the cardiac setting also supports the benefit of radiation-absorbing drapes: Jansen et al demonstrated that their use during endovascular treatment of peripheral artery disease significantly reduced occupational radiation exposure for operators, with reductions comparable to those seen in coronary interventions. The relative exposure of the primary operator was reduced by 66.5%, the relative exposure of the SO by 68.3%, and the relative exposure of the medical operator by 65.8%.[18]

Several factors may influence the variability in results, including operator behavior, procedural complexity, and the positioning of the radiation source.[19] Although adjustments for confounding factors like AK, DAP, and CAST improved the accuracy of comparisons, certain unmeasured variables, such as the operator's proximity to the radiation source, may have still affected the results. Furthermore, in this study the heightened awareness of radiation safety due to the presence of the drape may have altered operator behavior, potentially introducing bias.[19]

This study has several limitations. The lack of a sham drape introduces the possibility of performance bias. Additionally, despite randomization, baseline matching of patient and procedural characteristics between groups could not be ensured. Background radiation levels, which could influence technician exposure, were not accounted for. The single-center design may also limit generalizability. Moreover, the study primarily involved cardiac procedures, which may restrict extrapolation of the findings to other domains such as abdominal, neuro, or extremity work. Patients undergoing hybrid or multi-site therapies were excluded, which could represent a source of selection bias, as these procedures form a meaningful proportion of interventional practice. Finally, although blinding was attempted, complete operator blinding may not have been achievable, and any awareness of protective measures could have influenced operator technique. Future multicenter investigations addressing these aspects would be valuable to confirm and broaden the applicability of the results.

Conclusion

This study demonstrated that the use of radiation protection drapes significantly reduces radiation exposure for primary and secondary operators during radial, femoral, and pectoral procedures. The reductions were most notable in primary operators, reflecting their proximity to the radiation source, while secondary operators also benefitted substantially. These findings show the importance of incorporating radiation protection drapes into cath laboratory protocols to enhance occupational safety, particularly for personnel with the highest exposure risk.

Conflict of Interest

None declared.

Acknowledgments

The authors would like to express sincere gratitude to the Department of Cardiology at Vardhman Mahavir Medical College & Safdarjung Hospital for providing invaluable support and resources throughout the duration of this study. Special thanks are extended to their colleagues and staff members who contributed their expertise, dedication, and assistance in data collection, analysis, and patient care. Their collaboration and commitment were essential to the successful completion of this research.

Data Availability Statement

Data are available on request with Dr. Zubair Farooq (first author).

Authors' Contributions

All the authors equally conceptualized the study, designed the methodology, conducted data analysis, conducted research, contributed to data collection, drafted the manuscript, and visualized and wrote the review and did editing. All authors read and approved the final manuscript.

Ethical Approval

Approval for the study was obtained from the Institutional Ethics Committee, and the trial was registered with the Clinical Trials Registry of India (CTRI/2022/11/047008). All participants provided informed consent.

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Publication History

Article published online:
10 February 2026