Radiation Doses to Staff in a Hybrid Operating Room: An Anthropomorphic Phantom Study with Active Electronic Dosimeters

Radiation dose to staff from medical X-ray scatter in the orthopaedic theatre

PURPOSE

Given the growing demand for intraoperative imaging, there is increased concern for radiation dose for orthopaedic surgical staff. This study sought to determine the distribution of scatter radiation from fluoroscopic imaging in the orthopaedic surgical environment, with particular emphasis on the positions of personnel and the type of orthopaedic surgery performed.

METHODS

A radiation survey detector was deployed at various angles and distances around an anthropomorphic phantom. The scatter dose rate in microsieverts per hour (µSv/h) was recorded using consistent exposure parameters for five common surgical procedures. A C-arm unit produced radiation for the hip arthroscopy, hip replacement and knee simulations, whilst a mini C-arm unit produced fluoroscopy for the foot and hand simulations.

RESULTS

Readings were tabulated, and coloured heatmaps were generated from scatter measurements for each of the five procedures. Positions corresponding to the typical location of the surgical staff (surgeon, surgical assistant, anaesthetist, instrument (scrub) nurse, circulation (scout) nurse and anaesthetic nurse) were superimposed on heatmaps. The surgeon's proximity to the radiation source meant this position experienced the greatest amount of radiation in all five surgical procedures. Mini C-arm doses were considered low in all procedures for positions, with and without lead protection.

CONCLUSION

This investigation demonstrated the distribution of scattered radiation dose experienced at different positions within the orthopaedic surgical theatre. It reinforces the importance of staff increasing their distance from the primary beam where possible, reducing exposure time and increasing shielding with lead protection.

Radiation Exposure Reduction by Digital Variance Angiography in Lower Limb Angiography: A Randomized Controlled Trial

BACKGROUND

digital variance angiography (DVA) provides higher image quality than digital subtraction angiography (DSA). This study investigates whether the quality reserve of DVA allows for radiation dose reduction during lower limb angiography (LLA), and compares the performance of two DVA algorithms.

METHODS

this prospective block-randomized controlled study enrolled 114 peripheral arterial disease patients undergoing LLA into normal dose (ND, 1.2 µGy/frame, n = 57) or low-dose (LD, 0.36 µGy/frame, n = 57) groups. DSA images were generated in both groups, DVA1 and DVA2 images were generated in the LD group. Total and DSA-related radiation dose area product (DAP) were analyzed. Image quality was assessed on a 5-grade Likert scale by six readers.

RESULTS

the total and DSA-related DAP were reduced by 38% and 61% in the LD group. The overall visual evaluation scores (median (IQR)) of LD-DSA (3.50 (1.17)) were significantly lower than the ND-DSA scores (3.83 (1.00), p < 0.001). There was no difference between ND-DSA and LD-DVA1 (3.83 (1.17)), but the LD-DVA2 scores were significantly higher (4.00 (0.83), p < 0.01). The difference between LD-DVA2 and LD-DVA1 was also significant (p < 0.001).

CONCLUSIONS

DVA significantly reduced the total and DSA-related radiation dose in LLA, without affecting the image quality. LD-DVA2 images outperformed LD-DVA1, therefore DVA2 might be especially beneficial in lower limb interventions.

Assessing endovascular team performances in a hybrid room using the Black Box system: a prospective cohort study

BACKGROUND

The hybrid room (HR) is a complex, high-risk environment, requiring teams (surgeons, anesthesiologists, nurses, technologists) to master various skills, including the 'As Low As Reasonably Achievable' principle of radiation safety. This prospective single center cohort reports the first use of the Operating Room Black Box (ORBB) in a HR. This medical data recording system captures procedural and audio-visual data to facilitate structured team performance analysis.

METHODS

Patients planned for endovascular repair of an infrarenal abdominal aortic aneurysm (EVAR) or treatment of symptomatic iliac-femoral-popliteal atherosclerotic disease (Peripheral Vascular Interventions or PVI) were included. Validated measures and established assessment tools were used to assess (non-)technical skills, radiation safety performance and environmental distractions.

RESULTS

Six EVAR and sixteen PVI procedures were captured. Technical performance for one EVAR was rated 19/35 on the procedure-specific scale, below the 'acceptable' score of 21. Technical skills were rated above acceptable in all PVI procedures. Shared decision making and leadership were rated highly in 12/22 cases, whereas surgical communication and nurses' task management were rated low in 14/22 cases. Team members rarely stepped back from the C-arm during digital subtraction angiography. Radiation safety behavior was scored below 'acceptable' in 14/22 cases. A median (interquartile range) number of 12 (6-23) auditory distractions was observed per procedure.

CONCLUSIONS

The ORBB facilitates holistic workplace-based assessment of endovascular performance in a HR by combining objective assessment parameters and rating scale-based evaluations. Strengths and weaknesses were identified in team members' (non-)technical and radiation safety practices. This technology has the potential to improve vascular surgical practice, though human input remains crucial. (NCT04854278).

Impact of the incorrect use of lead drapes on staff and patient doses in interventional radiology

To evaluate the usefulness of commercially available scatter reduction drapes in mitigating staff exposure in interventional radiology and the potential harmful effects of drape malpositioning in terms of exposure levels to both patients and staff. An anthropomorphic phantom was irradiated on an angiography device under three scenarios: no drape and correct and incorrect drape positioning. Different levels of incorrect drape positioning relative to the field-of-view (FOV) were evaluated: slight, mild and severe. Real-time dosimeter systems (positioned on the operator's eye, chest and thyroid) were used to evaluate accumulative doses and dose rates. Different obstruction levels were evaluated and compared to the observer's perception. Additionally, patient exposure was evaluated for all scenarios using a dose area product (DAP). Up to a mild obstruction, by using the drape a dose reduction of up to 86% was obtained while a severe obstruction produced a 1000% increase in exposure, respectively for all dosimeter positions compared to the use of no drape. A similar order of magnitude was observed for patient exposure. Good agreement was obtained for the observer perception of the FOV obstruction up to 25% of the FOV; for larger obstructions, an overestimate of the obstruction was observed. Patient lead drapes can reduce staff doses in interventional radiology procedures even when mildly malpositioned and obscuring the FOV. Special attention to protective drape positioning is necessary, since the severe obstruction of the FOV results in a large increase in both operator and patient exposure.

Collimation and Exposure Parameter Influence Image Quality and Potential Radiation Dose to the Eye Lens of Personnel in Computed Radiography of the Canine Pelvis

Introduction: The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis.

Materials and Methods: A retrospective study of canine pelvic radiographs (N = 54) was undertaken to evaluate the relationship between image quality and the degree of field the collimation used. This was followed by a prospective cadaver study (N = 18) that assessed the effects on image quality and on scattered radiation dose of different collimation field areas and exposure parameters. All radiographs were analyzed for image quality using a Visual Grading Analysis (VGA) with three observers. Finally, the potential scattered radiation dose to the eye lens of personnel restraining a dog for pelvic radiographs was measured.

Results: The retrospective study showed a slightly better (statistically non-significant) VGA score for the radiographs with optimal collimation. Spatial and contrast resolution and image sharpness showed the greatest improvement in response to minimizing the collimation field. The prospective study showed slightly better VGA scores (improved image quality) with the optimal collimation. Increasing the exposure factors especially the tube current and exposure time (mAs) resulted in improved low contrast resolution and less noise in the radiographs. The potential eye lens radiation dose increased by 14, 28, and 40% [default exposures, increased the tube peak potential (kVp), increased mAs, respectively] as a result of reduced collimation (increased beam size).

Conclusion: The degree of collimation has no statistically significant on image quality in canine pelvic radiology for the range of collimation used but does have an impact on potential radiation dose to personnel in the x-ray room. With regard to radiation safety, increases in kVp are associated with less potential scatter radiation exposure compared to comparable increases in mAs.

Image quality and Dose Comparison of Three Mobile Intraoperative 3D imaging Systems in Spine Surgery

BACKGROUND

This study evaluated the radiation exposure and image quality for three intraoperative imaging systems (Airo, Spin, O-arm) using varying radiation dose settings in a single cadaver model.

METHODS

Axial images of L4-5 instrumentation were obtained using three manufacturer dose protocols for each system. Measurements included scattered radiation dose, subjective and objective image quality (IQ) and estimates of patient effective dose (ED). Four images per system were selected at each dose level. Using the Likert scale (1- best, 5- worst), nine reviewers rated the same 36 images. Objective IQ measures the degree of streak artifacts (lines with incorrect data from metal objects) in each image. A composite figure of merit (FOM) was derived based on ED and subjective and objective scores.

RESULTS

The best subjective IQ scores were Spin medium (1.44), high dose (1.78), and Airo (2.22) low dose. The best objective IQ scores were Airo (87.3), followed by Spin (89.1). ED low dose results in mSv included Airo (1.6), Spin (1.9) and O-arm (3.3). The ED high-dose results in mSv included Spin (4.6), Airo (9.7) and O-arm (9.9). Scatter radiation measurements for low dose in μGy included Spin (21.9), Airo (31.8) and O-arm (33.9). Scatter radiation for high dose in μGy included Spin (55.9), O-arm (104.5) and Airo (200). The best FOM score was for the Airo low dose, followed by Spin medium and high dose.

CONCLUSION

The selection of intraoperative imaging systems requires a greater understanding of the risks and benefits of radiation exposure and IQ.

Digital variance angiography allows about 70% decrease of DSA-related radiation exposure in lower limb X-ray angiography

Our aim was to investigate whether the previously observed higher contrast-to-noise ratio (CNR) and better image quality of Digital Variance Angiography (DVA) - compared to Digital Subtraction Angiography (DSA) - can be used to reduce radiation exposure in lower limb X-ray angiography. This prospective study enrolled 30 peripheral artery disease patients (mean ± SD age 70 ± 8 years) undergoing diagnostic angiography. In all patients, both normal (1.2 µGy/frame; 100%) and low-dose (0.36 µGy/frame; 30%) protocols were used for the acquisition of images in three anatomical regions (abdominal, femoral, crural). The CNR of DSA and DVA images were calculated, and the visual quality was evaluated by seven specialists using a 5-grade Likert scale. For investigating non-inferiority, the difference of low-dose DVA and normal dose DSA scores (DVA30-DSA100) was analyzed. DVA produced two- to three-fold CNR and significantly higher visual score than DSA. DVA30 proved to be superior to DSA100 in the crural region (difference 0.25 ± 0.07, p < 0.001), and there was no significant difference in the femoral (− 0.08 ± 0.06, p = 0.435) and abdominal (− 0.10 ± 0.09, p = 0.350) regions. Our data show that DVA allows about 70% reduction of DSA-related radiation exposure in lower limb X-ray angiography, providing a potential new radiation protection tool for the patients and the medical staff.

Comparison of patient and staff temple dose during fluoroscopically guided coronary angiography, implantable cardiac devices, and electrophysiology procedures

There is a paucity of literature comparing patient and staff dose during coronary angiography (CA), implantable cardiac devices, permanent pacemakers (PPM) and electrophysiology (EP) procedures and little noting dose to staff other than cardiologists. This study sought to compare patient and occupational dose during a range of fluoroscopically guided cardiac procedures. Radiation dose levels for the patients (n = 1651), cardiologists (n = 24), scrub (n = 32) and scout nurses (n = 35) were measured in a prospective single-centre study between February 2017 and August 2019. A comparison of dose during CA, device implantation, PPM insertion and EP studies was performed. Three angiographic units were used, with dosimeters worn on the temple of staff. Results indicated that occupational dose during PPM was significantly higher than other procedures. The cardiologist had the highest mean dose during biventricular implantable cardioverter-defibrillators; levels were approximately five times that of 'normal' pacemaker insertions. Transcatheter aortic valve implantations (TAVI) were associated with relatively high mean doses for both staff and patients and had a statistically significant higher (>2 times) mean patient dose area product than all other categories. TAVI workups were also related to higher mean cardiologist and scrub nurse dose. It was observed that the mean scrub nurse dose can exceed that of the cardiologist. The highest mean dose for Scout nurses were recorded during EP studies. Given the significantly higher temple dose associated with PPM insertion, cardiologists should consider utilizing ceiling mounted lead shields, lead glasses and/or skull caps where possible. Efforts should also be made to minimize the use of DSA during TAVI and TAVI workups to reduce cardiologist, nurse and patient dose.

A 5-YEAR RETROSPECTIVE ANALYSIS OF IONIZING RADIATION DOSE TO HYBRID OPERATING ROOM PERSONNEL IN SAUDI ARABIA

The annual average effective dose (ED) for operating room personnel (ORP) in Saudi Arabia was estimated from the period of 2015-2019 using thermoluminescent dosemeters. A retrospective analysis was conducted on annual EDs for 7530 ORP working across 52 hospitals. These workers were only exposed to radiation in the operating room. The annual average ED over the period of 5 years was found to be 0.59 mSv with no incidence of a dose above the annual dose limit of 20 mSv. The maximum annual ED reported was 15 mSv for an operating room worker in 2019. More than 88% of the workers received an annual ED of <1 mSv. The study concluded that the work environment in hybrid operating rooms across Saudi Arabia is safe. However, it is always recommended that workers take every protective measure when dealing with ionization radiation.

Automatic tool segmentation and tracking during robotic intravascular catheterization for cardiac interventions

Background

Cardiovascular diseases resulting from aneurism, thrombosis, and atherosclerosis in the cardiovascular system are major causes of global mortality. Recent treatment methods have been based on catheterization of flexible endovascular tools with imaging guidance. While advances in robotic intravascular catheterization have led to modeling tool navigation approaches with data sensing and feedback, proper adaptation of image-based guidance for robotic navigation requires the development of sensitive segmentation and tracking models without specificity loss. Several methods have been developed to tackle non-uniform illumination, low contrast; however, presence of untargeted body organs commonly found in X-ray frames taken during angiography procedures still presents some major issues to be solved.

Methods

In this study, a segmentation method was developed for automatic detection and tracking of guidewire pixels in X-ray angiograms. Image frames were acquired during robotic intravascular catheterization for cardiac interventions. For segmentation, multiscale enhancement filtering was applied on preprocessed X-ray angiograms, while morphological operations and filters were applied to refine the frames for pixel intensity adjustment and vesselness measurement. Minima and maxima extrema of the pixels were obtained to detect guidewire pixels in the X-ray frames. Lastly, morphological operation was applied for guidewire pixel connectivity and tracking in segmented pixels. Method validation was performed on 12 X-ray angiogram sequences which were acquired during in vivo intravascular catheterization trials in rabbits.

Results

The study outcomes showed that an overall accuracy of 0.995±0.001 was achieved for segmentation. Tracking performance was characterized with displacement and orientation errors observed as 1.938±2.429 mm and 0.039±0.040°, respectively. Evaluation studies performed against 9 existing methods revealed that this proposed method provides more accurate segmentation with 0.753±0.074 area under curve. Simultaneously, high tracking accuracy of 0.995±0.001 with low displacement and orientation errors of 1.938±2.429 mm and 0.039±0.040°, respectively, were achieved. Also, the method demonstrated higher sensitivity and specificity values compared to the 9 existing methods, with a relatively faster exaction time.

Conclusions

The proposed method has the capability to enhance robotic intravascular catheterization during percutaneous coronary interventions (PCIs). Thus, interventionists can be provided with better tool tracking and visualization systems while also reducing their exposure to operational hazards during intravascular catheterization for cardiac interventions.

Ergonomics in Interventional Radiology: Awareness Is Mandatory

Ergonomics in interventional radiology has not been thoroughly evaluated. Like any operators, interventional radiologists are exposed to the risk of work-related musculoskeletal disorders. The use of lead shielding to radiation exposure and the lack of ergonomic principles developed so far contribute to these disorders, which may potentially affect their livelihoods, quality of life, and productivity. The objectives of this review were to describe the different situations encountered in interventional radiology and to compile the strategies both available to date and in development to improve ergonomics.

A systematic review on the application of the hybrid operating room in surgery: experiences and challenges

The hybrid operating room has been widely applied in different surgery sub-specialties. We aim to identify the advantages of hybrid operating rooms by focusing on intraoperative imaging and explore what to do for further improving its application. We searched related literature in websites including Pubmed, MEDLINE, Web of science, using the keywords ("hybrid operating room" or "integrated operating room" or "multifunctional operating room") and ("surgery" or "technique" or "intervention" or "radiology"). All the searched papers were screened and underwent quality evaluation. A total of 30 literature was eventually identified after full-text screening. These articles covered 10 countries and presented data for 15,558 individuals. The median sample size was 536 (range 8-12,804). Application of the hybrid operating room in general surgery, neurosurgery, thoracic surgery, urology, gynaecologic and obstetrics surgery, cardiovascular surgery, was summarized. Four different operative indicators were applied (operative duration, mortality rate, operation success rate and complication rate). A hybrid OR could significantly increase the operation success rate and reduce operative duration, mortality rates, and complication rates. Further efforts could be made to reduce radiation exposure in the hybrid operating room and increase its cost-effectiveness ratio.