Measurements of surgeons' exposure to ionizing radiation dose: comparison of conventional and mini C-arm fluoroscopy

Safe usage of Mini 'C'-arm in operating room environment: Implications for clinical practice

BACKGROUND

Mini 'C'-arm machine is an advanced medical imaging device used primarily for intraoperative imaging during surgical, orthopaedic and emergency care procedures. Since the technology is based on ionising radiation, safe usage of Mini 'C'-arm machine is mandatory to protect patients and operating personnel.

OBJECTIVE

The main objective is to describe the various components related to patients, operator and equipment to ensure safe usage of Mini 'C'-arm machine. A comprehensive search strategy using the PEO (Population, Exposure, Outcome) framework was conducted using Embase, PubMed, Google Scholar and ResearchGate databases to identify suitable literature. The keywords used for the search included 'Fluoroscopy', 'Ionising Radiation' and 'surgical safety'.

KEY FINDINGS

Safe usage of Mini 'C'-arm equipment involves components of operator training, operator safety, patient safety, radiation dose, operating room logistics, handling of images and auditing of Mini 'C'-arm use.

CONCLUSION

Mini 'C'-arm provides an invaluable, portable imaging tool in a spectrum of general surgical and orthopaedic interventional procedures. However, safe usage of Mini 'C'-arm machine requires a multifaceted approach including operator responsibility and safety, patient protection, equipment maintenance, radiation dose awareness, documentation and sound reporting mechanisms.

Role of Laser Pointer in Budgeting Fluoroscopy-Time and Radiation Exposure

BACKGROUND

Literature on radiation exposure with use of the mini C-arm and value of having built-in laser guidance is limited. The purpose of this study was to determine whether laser guidance use on a mini C-arm fluoroscopy unit can reduce radiation exposure.

METHODS

Surgeons (N = 25) performed the same simulated surgical task, which involved obtaining "perfect circle" views of 2 cannulated screws placed into a cadaveric wrist, done with and without C-arm laser guidance. The testing order was randomized. Main outcomes were time to complete the task, number of shots required to complete the task, number of blank shots taken, radiation exposure, total dose area product (DAP), and total exposure time.

RESULTS

Laser guidance significantly reduced the percentage of surgeons who took blank shots, from 88% of the group without the laser to 12% of the group with the laser, and decreased the total average blank shots in the group from 3.5 to 0.1. While we found laser guidance led to shorter time to complete the task, decreased shots taken, and decreased exposure time and DAP, these findings only approached significance.

CONCLUSION

While debate continues regarding whether mini or standard C-arm is safest, it is clear that decreasing the overall number of exposures limits potential adverse effects. Our study demonstrated that when using a mini C-arm, laser guidance decreases the number of exposures required to capture an image. These findings warrant a larger study to define the specific exposure savings and indicate potential benefit of mini C-arm use with laser guidance.

Gonad irradiation from fluoroscopy during upper limb orthopaedic procedures in a UK District General Hospital

OBJECTIVES

To perform a dose assessment of radiation received to the surgeon's gonads when performing upper limb fluoroscopy-guided procedures when the C-arm may be positioned in between the surgeon's legs.

METHODS

A calibrated MDH-Radcal 2025 electrometer was used to read the radiation dose for a single exposure and a 5-s screening radiograph with the C-arm firing up and down. These were performed with and without a lead gown positioned over the ionisation chamber where it would ordinarily lie over gonads during surgery.

RESULTS

With the tube firing down and lead apron in place the single exposure (SE) recorded<0.01 uSv and screening exposure (SC) recorded 0.01 uSv. With the tube firing up, with lead the SE recorded 0.09 uSv and the SC 0.54 uSv. In the same situation without lead, the recordings were 0.13 uSv SE and 0. 65 uSv SC.

CONCLUSIONS

With the X-ray tube firing up, there is a measurable radiation dose to the area where the surgeons' gonads lie. The standard lead apron does not provide shielding of the gonads for a surgeon sitting down performing the operation with the tube firing up since the principal source of the radiation is below the edge of the apron and thus scatters up into the unprotected groin.

ADVANCES IN KNOWLEDGE

Fluoroscopy with conventional C-arm in upper limb procedures can cause scatter irradiation to gonads. The X-ray beam should always be fired from top to bottom otherwise large doses can be emitted and the lead gown is less protective.

Level of Supervision and Radiation Exposure of Senior Orthopedic Residents During Surgical Treatment of Proximal Femur Fracture

The sustained use of intraoperative fluoroscopy has led to increased use of minimally invasive surgical techniques, enhanced surgeon proficiency, improved anatomic corrections, reduced patient morbidity, earlier functional recovery, and decreased length of hospital stay. As a result, orthopedic attending surgeons and residents are exposed to more radiation, increasing the risk of cancer and radiation-induced cataracts compared with the general population and those who work in other surgical specialties. The magnitude of radiation exposure depends on the susceptibility of the tissues affected, medical specialty, the position of the C-arm, distance from the radiation beam, level of difficulty of the surgical procedure, surgeon experience, level of resident training, and level of supervision by the attending surgeon. However, little information is available on the effect of supervision level on radiation exposure for orthopedic senior residents. The goal of this study was to investigate whether level of supervision by the attending surgeon affects the radiation exposure of orthopedic senior residents during surgical treatment of proximal femur fracture with cephalomedullary nail fixation. This retrospective cohort study was performed from January 2019 to March 2019. No significant relationship between supervision level and radiation exposure of senior residents was observed. Supervision level does not significantly affect radiation exposure for senior residents; therefore, the implementation of standardized training in radiation safety may be a more essential measure to decrease radiation exposure. [Orthopedics. 2021;44(3):e402-e406.].

Occupational radiation exposure of orthopedists at different locations during pedicle screw insertion: An anthropomorphic phantom study

BACKGROUND

The purpose of this work was to evaluate orthopedic surgeons' exposure to occupational radiation doses from scattering using a mobile flat panel C-arm X-ray machine at different standing positions during an intraoperative pedicle screw implantation.

OBJECTIVE

Evaluate the radiation dose received by medical staff, by applying flat X-ray machine in surgical room during an intraoperative pedicle screw implantation.

METHODS

A mobile flat-panel C-arm X-ray machine at a dedicated orthopedic operating room was used to image an anthropomorphic female phantom which was set in a prone position on the operating table. The X-ray was projected horizontally, and 1 minute continuous fluoroscopy was used for lumbar spine and thoracolumbar spine during pedicle screw implantation. Scattering radiation doses to orthopedic surgeons were measured at different standing positions and body heights (50, 100, 150 cm above the ground) with and without limited collimations.

RESULTS

The dose area product (DAP) in this experiment is normalized as 343 μGy⋅m2. In the four areas, the lowest scattered radiation measured by DF is 11.2 vs. 0.7 μSv, outside and inside the lead suit, respectively, with or without restricted field, 150 cm above the ground, and the lowest scattered radiation dose inside the lead suit. It is 1.3 vs. 0.5 μSv. Comparing the highest dose of the TF at with the lowest dose of the DF, the average result is 73.7 vs. 11.1 μSv, P< 0.05.

CONCLUSIONS

Using a mobile flat-panel C-arm X-ray machine during a pedicle screw implantation, the minimum scattering radiation to surgeons was found to be at the terminal DF area based on the analysis of the scattering doses orthopedic surgeons were exposed to.

Establishing local diagnostic reference levels for mini C-arm use in upper limb surgery - A step towards national audit

AIMS

Under the Ionising Radiation Medical Exposure Regulations, hospitals using fluoroscopy and image intensifiers should monitor doses from exposures using ionising radiation. There is a need for national diagnostic reference levels to advise Orthopaedic and Plastic surgeons on safe screening times and radiation doses for patients having upper limb surgical procedures.

METHODS

Retrospective study of all patients who underwent upper limb surgical procedures requiring intra-operative mini C-arm image intensifier use at our hospital between 2013 and 2019. This included results from three machines in different rooms. Procedures were classified as closed and open procedures.

RESULTS

Information on a total of 2910 procedures over 6 years (June 2013 to June 2019) were obtained. 133 procedures with incomplete data and 4 cases of lower extremities were excluded. 1719 closed procedures had a median dose area product of 0.48 cGycm² and median screening time of 7 s, compared to 1054 open procedures, with a median dose area product of 1.88 cGycm² and median screening time of 28 s. National diagnostic reference levels are set at the third quartile and indicate the difference between good and poor practice. For diagnostic reference levels, we suggest a dose area product of 0.82 cGycm² and a screening time of 11 s for closed procedures and a dose area product of 3.07 cGycm² and screening time of 40 s for open procedures. Public Health England state that national diagnostic reference levels should be derived from multiple patients, radiology rooms and hospitals. Our data meets the first two criteria and is an initial step in establishing national diagnostic reference levels for upper limb mini C-arm use.

CONCLUSIONS

This large audit reports results, which, with further work across multiple hospital sites, should lead to establishing national diagnostic reference levels for mini C-arm fluoroscopy for upper limb Orthopaedic procedures.

Shielding effect of radiation dose reduction fiber during the use of C-arm fluoroscopy: a phantom study

This study evaluated the shielding effect of a newly developed dose-reduction fiber (DRF) made from barium sulfate, in terms of radiation doses delivered to patients' radiosensitive organs and operator during C-arm fluoroscopy and its impact on the quality of images. A C-arm fluoroscopy unit was placed beside a whole-body phantom. Radiophotoluminescent glass dosimeters were attached to the back and front of the whole-body phantom at 20 cm intervals. Radiation doses were measured without DRF and with it applied to the back (position 1), front (position 2) or both sides (position 3) of the phantom. To investigate the impact of DRF on the quality of fluoroscopic images, step-wedge and modulation transfer function phantoms were used. The absorbed radiation doses to the back of the phantom significantly decreased by 25.3-88.8% after applying DRF to positions 1 and 3. The absorbed radiation doses to the front of the phantom significantly decreased by 55.3-93.6% after applying DRF to positions 2 and 3. The contrast resolution values for each adjacent step area fell in the range 0.0119-0.0209, 0.0128-0.0271, 0.0135-0.0339 and 0.0152-0.0339 without and with DRF applied to positions 1, 2 and 3, respectively. The investigated DRF effectively reduces absorbed radiation doses to patients and operators without decreasing the quality of C-arm fluoroscopic images. Therefore, routine clinical use of the DRF is recommended during the use of C-arm fluoroscopy.

Radiation exposure in the treatment of pediatric supracondylar humerus fractures

PURPOSE

To determine the factors that influence radiation exposure during repair of supracondylar humerus fractures.

METHODS

Medical records of almost 200 children with supracondylar fractures were retrospectively analyzed for variables correlated with fluoroscopy time and radiation dose as measures of radiation exposure.

RESULTS

There was no statistically significant difference in fluoroscopy time (27 vs. 22 s p = 0.345) or direct radiation dose (0.394 vs. 0.318 mSv p = 0.290) between uniplanar and biplanar C-arm use. No statistically significant differences in fluoroscopy time or radiation dose were found for surgical technique, comorbid ipsilateral fractures, preoperative neurovascular compromise, or resident participation. There was a significant 8.3 s increase in fluoroscopy time (p = 0.022) and 0.249 mSv increase in radiation dose (p = 0.020) as the fracture type increased from II to III. An increase in one pin during CRPP resulted in a statistically significant 10.4 s increase in fluoroscopy time and a 0.205 mSv increase in radiation dose. There were significant differences between the physician with the lowest fluoroscopy time and radiation dose compared with the physicians with the two highest values for both fluoroscopy time and radiation dose (p < 0.01).

CONCLUSIONS

We found no significant difference in direct radiation exposure or fluoroscopy time when comparing biplanar to uniplanar C-arm use, resident participation, preoperative neurovascular compromise, or for comorbid ipsilateral fractures. Both outcomes increased significantly as fracture type increased from II to III and as the number of pins used during CRPP increased. Both outcomes were significantly different between the surgeons performing CRPP.

A Comparison of Image Quality and Radiation Exposure Between the Mini C-Arm and the Standard C-Arm

Background: The use of intraoperative fluoroscopy has become mandatory in osseous hand surgery. Due to its overall practicality, the mini C-arm has gained popularity among hand surgeons over the standard C-arm. This study compares image quality and radiation exposure for patient and staff between the mini C-arm and the standard C-arm, both with flat panel technology. Methods: An observer-based subjective image quality study was performed using a contrast detail (CD) phantom. Five independent observers were asked to determine the smallest circles discernable to them. The results were plotted in a graph, forming a CD curve. From each curve, an image quality figure (IQF) was derived. A lower IQF equates to a better image quality. The patients' entrance skin dose was measured, and to obtain more information about the staff exposure dose, a perspex hand phantom was used. The scatter radiation was measured at various distances and angles relative to a central point on the detector. Results: The IQF was significantly lower for the mini C-arm resulting in a better image quality. The patients' entrance dose was 10 times higher for the mini C-arm as compared with the standard C-arm, and the scatter radiation threefold. Conclusions: Due to its improved image quality and overall practicality, the mini C-arm is recommended for hand surgical procedures. To ensure that the surgeons' radiation exposure is not exceeding the safety limits, monitoring radiation exposure using mini C-arms with flat panel technology during surgery should be done in a future clinical study.

Elevated Radiation Exposure Associated With Above Surface Flat Detector Mini C-Arm Use

Background: This study aims to test the hypothesis that: (1) radiation exposure is increased with the intended use of Flat Surface Image Intensifier (FSII) units above the operative surface compared with the traditional below-table configuration; (2) this differential increases in a dose-dependent manner; and (3) radiation exposure varies with body part and proximity to the radiation source. Methods: A surgeon mannequin was seated at a radiolucent hand table, positioned for volar distal radius plating. Thermoluminescent dosimeters measured exposure to the eyes, thyroid, chest, hand, and groin, for 1- and 15-minute trials from a mini C-arm FSII unit positioned above and below the operating surface. Background radiation was measured by control dosimeters placed within the operating theater. Results: At 1-minute of exposure, hand and eye dosages were significantly greater with the flat detector positioned above the table. At 15-minutes of exposure, hand radiation dosage exceeded that of all other anatomic sites with the FSII in both positions. Hand exposure was increased in a dose-dependent manner with the flat detector in either position, whereas groin exposure saw a dose-dependent only with the flat detector beneath the operating table. Conclusions: These findings suggest that the surgeon's hands and eyes may incur greater radiation exposure compared with other body parts, during routine mini C-arm FSII utilization in its intended position above the operating table. The clinical impact of these findings remains unclear, and future long-term radiation safety investigation is warranted. Surgeons should take precautions to protect critical body parts, particularly when using FSII technology above the operating with prolonged exposure time.

Effect of metallic tools on scattered radiation dose during the use of C-arm fluoroscopy in orthopaedic surgery

This study investigated the effect of metallic tools on the scattered radiation dose delivered to surgeons' radiosensitive organs while simulating hip surgery using C-arm fluoroscopy. Two phantoms, a pelvis and a Rando phantom, were used to simulate a patient and a surgeon in this study. Photoluminescence dosimeters were inserted into the Rando phantom in the positions of the eye, thyroid and gonad. A drill was positioned above the hip of the pelvis phantom or beside the pelvis phantom of the same height. For each drill location, the scattered radiation dose was measured when the angle to the operator phantom was 45°; this was repeated when the angle was 90°. The scattered radiation doses to the eye, thyroid and gonad when the drill was placed beside the pelvis phantom with 90° angulation to the operator phantom were significantly lower than the reference values and those when the drill was placed beside the pelvis phantom at a 45° angulation to the operator phantom. The scattered radiation doses to the eye and thyroid when the drill was placed above the hip were significantly lower than the references values. Of the four different scenarios, the scattered radiation doses to the eye, thyroid and gonad were lowest when the drill was placed beside the pelvis phantom with 90° angulation. This study showed that the scattered radiation doses to radiosensitive organs were affected by the location and angle of the metallic tools in relation to the operator. Therefore, orthopedic surgeons should consider the effect of metallic tools on the scattered radiation dose during intraoperative use of C-arm fluoroscopy.

Radiation Exposure to Surgeon and Assistant During Flat Panel Mini C-Arm Fluoroscopy in Hand and Wrist Surgical Procedures

PURPOSE

During mini C-arm fluoroscopy, both the patient and surgical team are exposed to scatter radiation. The objective of this study was to quantify body, thyroid, and hand radiation exposure to surgeon and assistant during intraoperative use of flat panel mini C-arm fluoroscopy in hand and wrist surgical procedures.

METHODS

Over 5 months, the surgeon's and assistant's radiation exposure was recorded during all osseous hand and wrist surgical procedures. Whole-body and thyroid radiation exposure were measured with 2 types of dosimeters: a photon thermoluminescence detector and a RaySafe i2 real-time dosimeter. Ring dosimeters were used to quantify hand radiation exposure.

RESULTS

Mini C-arm fluoroscopy was used in 94 surgical procedures. Total fluoroscopy time was 1,996 seconds and varied between surgical procedures (range, 1-152 seconds; median, 11 seconds). No thermoluminescence detector photon dosimeter exceeded the threshold limit of 0.1 mSv. The RaySafe i2 real-time dosimeters recorded a cumulated dose of 0.029 mSv for the body and 0.012 mSv for the thyroid position of the surgeon. The assistant received a cumulated dose of 0.011 mSv for the body and 0.011 mSv for the thyroid position. The ring dosimeters showed a cumulated dosage of 1.28 mSv for the surgeon and 0.20 mSv for the assistant.

CONCLUSIONS

Our results show that the surgeon's and assistant's body, thyroid, and hands were exposed to acceptable levels of scatter radiation during intraoperative use of the flat panel mini C-arm. The surgeon received the highest radiation exposure: 2.9% of the yearly radiation limits for the body, 0.05% for the thyroid position, and 2.56% for the hands. The assistant was exposed to less scatter radiation: 1.1% for the body, 0.04% for the thyroid, and 0.4% for the hands.

CLINICAL RELEVANCE

This study quantified radiation levels to which surgeon and assistant are exposed during mini C-arm fluoroscopy in hand and wrist surgical procedures.

Mini C-Arm Fluoroscopy: Does Its Configuration Matter for Radiation Exposure to the Surgeon?

BACKGROUND

The risk of occupational radiation exposure to the surgeon associated with the use of a mini C-arm has yet to reach a wide consensus. Using a distal radius fracture surgery model, we tested the hypothesis that radiation exposure to the surgeon's critical body parts is independent of mini C-arm configuration.

METHODS

An anthropomorphic mannequin (representing the upper body of a 60" male surgeon) was seated at a hand table as if operating on a volar-plated wrist Sawbone model. Thermoluminescent dosimeters measured radiation exposure to the surgeon's eyes, thyroid, chest, hand, and groin from a mini C-arm fluoroscopy unit in 3 commonly used configurations: vertical (source above table), inverted (source below table), and horizontal (with beam parallel to table surface). The fluoroscope scanned the wrist model for 15 continuous minutes in triplicate for each orientation.

RESULTS

Radiation to the hand was significantly greatest in all mini C-arm positions compared with all other anatomic sites irrespective of C-arm position. Hand radiation exposure was greatest in the horizontal position (2887.09 mrem), versus the vertical and inverted positions (59.79 mrem, 31.10 mrem, P < .001). Eye radiation exposure was significantly greater in the inverted position (2.33 mrem) compared with the vertical (0.67 mrem, P = .024), and horizontal positions (0.33 mrem, P = .012). No significant difference in radiation exposure was found at the thyroid, chest, and groin sites, at each of the 3 C-arm configurations.

CONCLUSIONS

The model's hand received almost 1000 times more radiation exposure than all other anatomic sites with statistically greatest radiation exposure sustained in the horizontal position. Eye radiation exposure with the C-arm in the inverted position (below the table) was also significantly greater.

A Report on Occupational Ionizing Radiation Exposure by an Orthopedic Surgeon in a National Health-care Setting - Clinical Case Perspective

INTRODUCTION

The purpose of the study was to have a general overview of the current understanding of occupational ionizing radiation exposure among health care workers and to explore the potential risks of such exposure to orthopedic surgeons working in national health-care setting.

METHODS

The author conducted 4 months measurement of ionizing radiation exposure using body and finger dosimeter. The result used to estimate the annual occupational ionizing radiation exposure. The final results compared to previously published data with general exploration of the risk associated with such exposure through literature review.

RESULTS

The results indicate that the current exposure is below that of the dose limit set by the International Commission on Radiological Protection (ICRP) and found to be similar to previously published data.

CONCLUSION

Health-care employees are the largest group exposed to ionizing radiation [1, 2]. The carcinogenic effect of high dose of radiation on humans is well documented [1, 2], but the long-term effect of exposure to low doses of ionizing radiation is not clear. Some published studies indicate increased risk of cancer among female orthopedic surgeon which may or may not be directly linked to ionizing radiation exposure. We should reinforce the main principles recommended by the ICRP: Justification, optimization of protection, and dose limitation.

Radiation exposure and the orthopedic surgeon's hand: Measurement of the equivalent dose over 13 months

Exposure to ionizing radiation in the operating room is governed by practical prevention and protection measures on the international, national and local levels. We evaluated the equivalent dose to the hand of an orthopedic surgeon over 13 months. An orthopedic surgeon wore a ring dosimeter on the ring finger of his right hand for all surgical procedures requiring intraoperative fluoroscopy between March 2014 and April 2015. Monthly doses were evaluated by the IRSN over the study period. The number and type of procedures were compiled as well as the type of fluoroscopy unit used. Four hundred procedures were performed during this period, including 182 with fluoroscopy. The equivalent cumulative dose at the hand was 4,75 mSv. No correlation was found with the type of procedure or type of fluoroscopy unit (conventional or mini C-arm). Equivalent doses were below the annual regulatory limit in France of 500 mSv. These results are consistent with those reported in the literature. However, recent studies have noted that both younger surgeons in training and more experienced surgeons must remember to use radiation protection measures.

Performances of a protector against scattered radiation during intraoperative use of a C-arm fluoroscope

The scattered radiation protector for mobile x-ray systems, Creative Valuable Protector-2, has been recently developed. However, there have been no studies investigating the effects of this device. We aim to investigate the effects of the scattered radiation protector on the equivalent doses from scattered radiation delivered to radiosensitive organs while simulating spine surgery using a C-arm fluoroscope. Chest and rando phantoms were used to simulate a patient and a surgeon in this study. The equivalent dose from scattered radiation to radiosensitive organs was measured in four different situations according to the use of the scattered radiation protector and the C-arm configuration. To compare the quality of the images with and without the scattered radiation protector, an acryl step phantom with five steps was used, and the contrast resolution of each step was calculated. The equivalent dose from the scattered radiation to the surgeon's eye, thyroid, and gonad decreased significantly by using the scattered radiation protector for both the Posteroanterior (PA) (p  <  0.001) and Anteroposterior (AP) (p  <  0.001) C-arm configurations. The installation of the scattered radiation protector also reduced the direct radiation dose to the chest phantom. A scattered map showed that scattered radiation doses decreased by approximately 50% for the PA configuration and 75% for the AP configuration by using the scattered radiation protector. Before and after installation of the scattered radiation protector, the contrast resolution of each adjacent step area was 0.025-0.404 and 0.216-0.421. The scattered radiation protector was effective in reducing not only the equivalent dose from scattered radiation to the surgeon's radiosensitive organs, but also the direct radiation dose to the patient. This was all achieved without decreasing the quality of the C-arm fluoroscopic images.