Radiation Safety during Spine Interventions

Radiation exposure in fluoroscopy guided spinal interventions: A prospective observational study of standard practice in a physiatry academic center

Context

Fluoroscopy is the recommended image guidance modality for most spinal pain interventions. However, it exposes interventional pain physicians to chronic ionizing radiation, with known risks to the eye, skin, and hand. The use of protective glasses and gloves is variable among pain physicians.

Objectives

To document the total radiation exposure (mSv) by pain physicians to their eyes, hands and chest in an academic setting including various spinal interventions.

Methods

Four pain physicians wore a finger, head/collar (equivalent to eye exposure) and chest dosimeter over and under their lead apron during a three-month period where they performed their usual fluoroscopy-guided interventions, including close supervision of trainees. We calculated an average exposure per intervention and extrapolated the recorded exposure to a maximum, worst-case scenario of a caseload of 13 procedures per day, 5 days a week and 52 weeks per year.

Results

Four pain physicians of variable experience performed 15 different types of procedures on 607 patients throughout the study period. The yearly maximum exposure scenarios for each pain physician were all below the Canadian Nuclear Safety Commission thresholds for nuclear energy workers: for the hands (31.56 mSv, 25.67 mSv, 20.59 mSv, 21.51 mSv; threshold = 500 mSv), eyes (16.01 mSv, 18.64 mSv, 24.08 mSv, 18.68 mSv; threshold = 50 mSv) and chest over the lead apron (28.27 mSv, 46.91 mSv, 30.00 mSv, 40,03 mSv; whole body threshold = 50 mSv), with some doses even below general population thresholds. The exposure under the lead apron was 0 mSv for each pain physician.

Conclusion

The standard practice of an interventional pain physician using fluoroscopy in this academic setting is below radiation exposure regulations, even in a theoretical, worst-case, maximum exposure scenario. Standard radiation protection practices such as the use of lead aprons and thyroid shields should still be used. However, this data is reassuring for pain physicians with a practice in fluoroscopy-guided interventions who wish to not use protective glasses or gloves.

Radiation Protection in Interventional Radiology

There has been a rapid development in the field of interventional radiology over recent years, and this has led to a rapid increase in the number of interventional radiology procedures being performed. There is, however, a growing concern regarding radiation exposure to the patients and the operators during these procedures. In this article, we review the basics of radiation exposure, radiation protection techniques, radiation protection tools available to interventional radiologists, and radiation protection during pregnancy.

Radiation Concerns for the Neuroanesthesiologists

With the advent of minimally invasive neurosurgical techniques and rapid innovations in the field of neurointervention, there has been a sharp rise in diagnostic and therapeutic modalities requiring radiation exposure. Neuroanesthesiologists are currently involved in various procedures inside as well as outside the operating room (OR) like intensive care units, interventional suites, and gamma knife units. The ambit expands from short-lasting diagnostic scans to lengthy therapeutic procedures performed under fluoroscopic guidance. Hence, a modern-day neuroanesthesiologist has to bear the brunt of the radiation exposure in both inside and outside the OR. However, obliviousness and nonadherence to the relevant radiation safety measures are still prevalent. Radiation protection and safety are topics that need to be discussed with new vigor in the light of current practice.

Ergonomics in IR

Ergonomic research in the field of interventional radiology remains limited. Existing literature suggests that operators are at increased risk for work-related musculoskeletal disorders related to the use of lead garments and incomplete knowledge of ergonomic principles. Data from existing surgical literature suggest that musculoskeletal disorders may contribute to physician burnout and female operators are at a higher risk of developing musculoskeletal disorders. This review article aims to summarize the existing ergonomic challenges faced by interventional radiologists, reiterate existing solutions to these challenges, and highlight the need for further ergonomic research in multiple areas, including burnout and gender.

Does nonexistent of your hands on the screen guarantee no radiation exposure to your body? - Study on exposure of the practitioner's hands to radiation during C-arm fluoroscopy-guided injections and effectiveness of a new shielding device

Observational phantom study.This study aimed to evaluate the radiation exposure dose of practitioner's hands when performing C-arm guided procedures and to determine the usefulness of our newly designed radiation shielding device.C-arm guided procedures including lumbar transforaminal epidural steroid injections (TFESIs) are commonly used for pain control induced by lumbar radiculopathy. The practitioner's hands are vulnerable to radiation exposure because of the long exposure time and short distance from the radiation resource. No studies to date have reported the cumulative exposure of the physician's hands according to location and exposure time.Using a chest phantom irradiated with X-rays under lumbar TFESI conditions, cumulative scatter radiation dose was measured at 36 points using a dosimeter. The measurements were checked at 1, 3, 5, 10 minutes of radiation exposure. The experiment was repeated using our newly designed shielding device.Significant radiation accumulation was observed in the field where the practitioner's hands might be placed during C-arm guided procedures. The further the distance from the radiation resource and the shorter the exposure time, the smaller was the cumulative radiation expose dose. The new shielding device showed an excellent shielding rate (66.0%-99.9%) when the dosimeter was within the shielding range. However, at some points, increased accumulated radiation exposure dose was observed, although the dosimeter was within the range of the shielding device.To reduce radiation exposure of the practitioner's hands when performing C-arm-guided procedures, the radiation exposure time should be decreased and a greater distance from the radiation resource should be maintained. When using our shielding device, placing the hand close to the device surface and minimizing the time using fluoroscopy minimized the radiation exposure of the hand.

Is lead shielding of patients necessary during fluoroscopic procedures? A study based on kyphoplasty

OBJECTIVE

To determine the benefits, risks, and limitations associated with wrapping a patient with lead shielding during fluoroscopy-guided kyphoplasty procedures as a way to reduce operator radiation exposure.

MATERIALS AND METHODS

An anthropomorphic phantom was used to mimic a patient undergoing a kyphoplasty procedure under fluoroscopic guidance. Radiation measurements of the air kerma rate (AKR) were made at several locations and under various experimental conditions. First, AKR was measured at various angles along the horizontal plane of the phantom and at varying distances from the phantom, both with and without a lead apron wrapped around the lower portion of the phantom (referred to here as phantom shielding). Second, the effect of an operator's apron was simulated by suspending a lead apron between the phantom and the measurement device. AKR was measured for the four shielding conditions-phantom shielding only, operator apron only, both phantom shielding and operator apron, and no shielding. Third, AKR measurements were made at various heights and with varying C-arm angle.

RESULTS

At all locations, the phantom shielding provided no substantial protection beyond that provided by an operator's own lead apron. Phantom shielding did not reduce AKR at a height comparable to that of an operator's head.

CONCLUSIONS

Previous reports of using patient shielding to reduce operator exposure fail to consider the role of an operator's own lead apron in radiation protection. For an operator wearing appropriate personal lead apparel, patient shielding provides no substantial reduction in operator dose.

Patient Dose in Fluoroscopically Guided Cervical Discectomy and Fusion

Cervical discectomy and fusion (CDF) is a minimally invasive procedure, where the accurate placement of the implants is accomplished using fluoroscopic guidance. Therefore, the evaluation of the radiation dose becomes mandatory. The purpose of the current study was to assess patient dose during fluoroscopically guided anterior and/or posterior CDF procedures. Thirty-three patients undergoing single or multiple-level CDF were studied using a mobile C-arm system. Data regarding fluoroscopy time (FT), air kerma area product (KAP) and cumulative dose (CD) were recorded. Patient entrance surface dose (ESD), thyroid absorbed dose and effective dose (ED) were calculated from KAP measurements, utilizing the CALDoseX software. The average FT was 0.12 min (range 0.02-0.48 min), resulting to a KAP value of 0.21 Gy cm2 (range 0.01-1.46 Gy cm2) and a CD value of 0.96 mGy (range 0.04-6.58 mGy). The ESD ranged between 0.08 and 13.58 mGy (average 1.95 mGy), the ED between 0.001 and 0.097 mSv (average 0.015 mSv), while the dose absorbed by the thyroid ranged between 0.01 and 1.12 mGy (average 0.194 mGy). The dose associated with the CDF procedure is very low, comparable to that delivered by a lateral X-ray radiograph of the cervical spine. However, higher doses can be revealed, due to the non-optimum use of the X-ray system and extended FTs, mainly affected by complex clinical conditions, as well as the experience of the neurosurgeon. Additional studies need to be conducted for further investigation of the patient dose from the CDF procedure.

RADIATION PROTECTION IN AN INTERVENTIONAL LABORATORY: A COMPARATIVE STUDY OF AUSTRALIAN AND SAUDI ARABIAN HOSPITALS

This study aimed to investigate whether the use of protection devices and attitudes of interventional professionals (including radiologists, cardiologists, vascular surgeons, medical imaging technicians and nurses) towards radiation protection will differ between Saudi Arabian and Australian hospitals. Hard copies of an anonymous survey were distributed to 10 and 6 clinical departments in the Eastern province of Saudi Arabia and metropolitan hospitals in Western Australia, respectively. The overall response rate was 43 % comprising 110 Australian participants and 63 % comprising 147 Saudi participants. Analysis showed that Australian respondents differed significantly from Saudi respondents with respect to their usages of leaded glasses (p < 0.001), ceiling-suspended lead screen (p < 0.001) and lead drape suspended from the table (p < 0.001). This study indicates that the trained interventional professionals in Australia tend to adhere to benefit from having an array of tools for personal radiation protection than the corresponding group in Saudi Arabia.

Radiation Protection for the Fluoroscopy Operator and Staff

OBJECTIVE

The purposes of this article are to review available data regarding the range of protection devices and garments with a focus on eye protection and to summarize techniques for reducing scatter radiation exposure.

CONCLUSION

Fluoroscopy operators and staff can greatly reduce their radiation exposure by wearing properly fitted protective garments, positioning protective devices to block scatter radiation, and adhering to good radiation practices. By understanding the essentials of radiation physics, protective equipment, and the features of each imaging system, operators and staff can capitalize on opportunities for radiation protection while minimizing ergonomic strain. Practicing and promoting a culture of radiation safety can help fluoroscopy operators and staff enjoy long, productive careers helping patients.

Radiation exposure to the surgeon and the patient during posterior lumbar spinal instrumentation: a prospective randomized comparison of navigated versus non-navigated freehand techniques

STUDY DESIGN

A prospective randomized study.

OBJECTIVE

To compare occupational radiation exposure to the surgeon, as well as the patient, during posterior lumbar spine instrumentation in 10 navigated cases (navigated) versus 11 cases using the freehand technique (non-navigated).

SUMMARY OF BACKGROUND DATA

The use of navigation increases the accuracy of posterior lumbar instrumentation.A further speculated benefit of navigation is the reduction of radiation exposure of the surgeon. However, this has so far not been evaluated in such comparative manner.

METHODS

Radiation exposure to the surgeon was measured by digital dosimeters placed at the level of the eye, chest, and dominant forearm. Radiation exposure was measured from the time of positioning of the patient to the end of the procedure both for navigated (intraoperative 3-dimensional [3D] fluoroscopy-based) and non-navigated (2-dimensional fluoroscopy-guided) freehand posterior lumbar spine instrumentations. A 3D fluoroscopic scan was routinely performed at the end of the procedure for all patients.

RESULTS

Patients were distributed evenly in the 2 groups in terms of sex, age, body mass index, and the number of operated levels. The accumulated radiation dose for the surgeon was significantly higher in the non-navigated group; up to 9.96 times. The radiation dose for the patient was higher with the freehand technique, 1884.8 cGy·cm (non-navigated) versus 887 cGy·cm (navigated), without reaching a statistically significant level.

CONCLUSION

Radiation exposure to the surgeon during pedicle screw placement with the freehand technique is up to 9.96 times greater than with the use of navigation. In the latter group, the only radiation exposure comes from the preoperative-level control and positioning of the 3D C-arm before 3D fluoroscopic acquisition. Furthermore, neuronavigation also reduces the cumulative dose for the patient.

LEVEL OF EVIDENCE

2.

Catheter-based therapies for deep vein thrombosis

The basic treatment of deep vein thrombosis (DVT) over the past several decades has consisted of anticoagulation only, with inferior vena cava filtration for those who either failed or could not tolerate anticoagulation. Until recently no randomized trials had studied the efficacy of thrombolysis in DVT despite advances in techniques and technologies for endovascular clot removal. This article is a review of the current evidence on catheter-based therapies for patients with DVT. Technical considerations to improve outcome as well as optimal patient selection are discussed.

How Effective Are Radiation Reducing Gloves in C-arm Fluoroscopy-guided Pain Interventions?

Background

The physician's hands are close to the X-ray field in C-arm fluoroscopy-guided pain interventions. We prospectively investigated the radiation attenuation of Proguard RR-2 gloves.

Methods

In 100 cases, the effective doses (EDs) of two dosimeters without a radiation-reducing glove were collected. EDs from the two dosimeters-one dosimeter wrapped with a glove and the other dosimeter without a glove- were also measured at the side of the table (Group 1, 140 cases) and at a location 20 cm away from the side of the table (Group 2, 120 cases). Mean differences such as age, height, weight, radiation absorbed dose (RAD), exposure time, ED, and ratio of EDs were analyzed.

Results

In the EDs of two dosimeters without gloves, there were no significant differences (39.0 ± 36.3 µSv vs. 38.8 ± 36.4 µSv) (P = 0.578). The RAD (192.0 ± 182.0 radcm²) in Group 2 was higher than that (132.3 ± 103.5 radcm²) in Group 1 (P = 0.002). The ED (33.3 ± 30.9 µSv) of the dosimeter without a glove in Group 1 was higher than that (12.3 ± 8.8 µSv) in Group 2 (P < 0.001). The ED (24.4 ± 22.4 µSv) of the dosimeter wrapped with a glove in Group 1 was higher than that (9.2 ± 6.8 µSv) in Group 2 (P < 0.001). No significant differences were noted in the ratio of EDs (73.5 ± 6.7% vs. 74.2 ± 9.3%, P = 0.469) between Group 1 and Group 2.

Conclusions

Proguard RR-2 gloves have a radiation attenuation effect of 25.8-26.5%. The radiation attenuation is not significantly different by intensity of scatter radiation or the different RADs of C-arm fluoroscopy.

Effect of real-time radiation dose feedback on pediatric interventional radiology staff radiation exposure

PURPOSE

To measure and compare individual staff radiation dose levels during interventional radiologic (IR) procedures with and without real-time feedback to evaluate whether it has any impact on staff radiation dose.

MATERIALS AND METHODS

A prospective trial was performed in which individuals filling five different staff roles wore radiation dosimeters during all IR procedures during two phases: a 12-week "closed" phase (measurements recorded but display was off, so no feedback was provided) and a 17-week "open" phase (display was on and provided real-time feedback). Radiation dose rates were recorded and compared by Mann-Whitney U test.

RESULTS

There was no significant difference in median procedure time, fluoroscopy time, or patient dose (dose-area product normalized to fluoroscopy time) between the two phases. Overall, the median staff dose was lower in the open phase (0.56 µSv/min of fluoroscopy time) than in the closed phase (3.01 µSv/min; P < .05). The IR attending physician dose decreased significantly for procedures for which the physicians were close to the patient, but not for ones for which they were far away.

CONCLUSIONS

A radiation dose monitoring system that provides real-time feedback to the interventional staff can significantly reduce radiation exposure to the primary operator, most likely by increasing staff compliance with use of radiation protection equipment and dose reduction techniques.

Feasibility study of needle placement in percutaneous vertebroplasty: cone-beam computed tomography guidance versus conventional fluoroscopy

OBJECTIVE

To investigate the accuracy, procedure time, fluoroscopy time, and dose area product (DAP) of needle placement during percutaneous vertebroplasty (PVP) using cone-beam computed tomography (CBCT) guidance versus fluoroscopy.

MATERIALS AND METHODS

On 4 spine phantoms with 11 vertebrae (Th7-L5), 4 interventional radiologists (2 experienced with CBCT guidance and two inexperienced) punctured all vertebrae in a bipedicular fashion. Each side was randomization to either CBCT guidance or fluoroscopy. CBCT guidance is a sophisticated needle guidance technique using CBCT, navigation software, and real-time fluoroscopy. The placement of the needle had to be to a specific target point. After the procedure, CBCT was performed to determine the accuracy, procedure time, fluoroscopy time, and DAP. Analysis of the difference between methods and experience level was performed.

RESULTS

Mean accuracy using CBCT guidance (2.61 mm) was significantly better compared with fluoroscopy (5.86 mm) (p < 0.0001). Procedure time was in favor of fluoroscopy (7.39 vs. 10.13 min; p = 0.001). Fluoroscopy time during CBCT guidance was lower, but this difference is not significant (71.3 vs. 95.8 s; p = 0.056). DAP values for CBCT guidance and fluoroscopy were 514 and 174 mGy cm(2), respectively (p < 0.0001). There was a significant difference in favor of experienced CBCT guidance users regarding accuracy for both methods, procedure time of CBCT guidance, and added DAP values for fluoroscopy.

CONCLUSION

CBCT guidance allows users to perform PVP more accurately at the cost of higher patient dose and longer procedure time. Because procedural complications (e.g., cement leakage) are related to the accuracy of the needle placement, improvements in accuracy are clinically relevant. Training in CBCT guidance is essential to achieve greater accuracy and decrease procedure time/dose values.

Radiation exposure to the surgeon during open lumbar microdiscectomy and minimally invasive microdiscectomy: a prospective, controlled trial

STUDY DESIGN

This is a prospective in vivo study comparing radiation exposure to the surgeon during 10 minimally invasive lumbar microdiscectomy cases with 10 traditional open discectomy cases as a control.

OBJECTIVE

Radiation exposure to the eye, chest, and hand of the operating surgeon during minimally invasive surgery (MIS) and open lumbar microdiscectomy were measured. The Occupational Exposure Guidelines were used to calculate the allowable number of cases per year from the mean values at each of the 3 sites.

SUMMARY OF BACKGROUND DATA

Fluoroscopy is a source of ionizing radiation and as such, is a potential health hazard with continued exposure during surgery. Presently, radiation exposure to the surgeon during MIS lumbar microdiscectomy is unknown.

METHODS

Radiation exposure to the surgeon (millirads [mR]) per case was measured by digital dosimeters placed at the level of the thyroid/eye, chest, and dominant forearm. Other data collected included operative side and level, side of the surgeon, side of the x-ray source, total fluoroscopy time, and energy output.

RESULTS

The average radiation exposure to the surgeon during open cases was thyroid/eye 0.16 ± 0.22 mR, chest 0.21 ± 0.23 mR, and hand 0.20 ± 0.14 mR. During minimally invasive cases exposure to the thyroid/eye was 1.72 ± 1.52 mR, the chest was 3.08 ± 2.93 mR, and the hand was 4.45 ± 3.75 mR. The difference between thyroid/ eye, chest, and hand exposure during open and minimally invasive cases was statistically significant (P = 0.010, P = 0.013, and P = 0.006, respectively). Surgeons standing in an adjacent substerile room during open cases were exposed to 0.2 mR per case.

CONCLUSION

MIS lumbar microdiscectomy cases expose the surgeon to significantly more radiation than open microdiscectomy. One would need to perform 1623 MIS microdiscectomies to exceed the exposure limit for whole-body radiation, 8720 cases for the lens of the eye, and 11,235 cases for the hand. Standing in a substerile room during x-ray localization in open cases is not fully protective.

The Influence of Angiography Table Shields and Height on Patient and Angiographer Irradiation During Interventional Radiology Procedures

PURPOSE

To quantify the influence of angiography table height on patient and angiographer irradiation, as compared with other routine protective measures such as the use of protective shields hanging at the tableside and from the ceiling of angiography suites.

METHODS

An experimental study was carried out in which a phantom (substitute for a human body) placed on the angiography table was irradiated by pulsed fluoroscopy. Entrance exposure rates were measured at the phantom surface (surrogate of patient skin exposure by incident X-ray beam) and at 60 cm from the phantom (analog to angiographer skin exposure by scatter). Exposure rates were measured at levels corresponding to the knees, testes, waist, xyphoid appendix, shoulders, and eyes of an angiographer 178 cm tall. Measurements were repeated at angiography table heights of 85, 95, 105, and 110 cm from the floor, with and without protective shields.

RESULTS

Moving the table from its highest to lowest position increased by 32% the phantom entrance exposure but decreased scatter to the angiographer. Scatter to the angiographer could be reduced most by using the protective shields (30-105 times less), but low table heights provided relatively more important protection (412-1121 muSv/hr reduction, or 15-72% scatter reduction) when shields were not used (e.g., for unprotected regions of the angiographer's body such as the hands).

CONCLUSION

Working at lower table heights provides a little additional protection to exposed body parts of angiographers, at the cost of somewhat higher patient exposure. Although small, this incremental protection could be clinically relevant in the long term. The choice of table position should be a compromise based on multiple factors, including at least patient exposure, scatter to angiographers, and angiographer comfort.

An investigation of operator exposure in interventional radiology

A study was conducted to investigate how operator exposure in interventional radiology is affected by various common fluoroscopic imaging conditions. Stray radiation levels surrounding the imaging chain of a C-arm angiographic system were measured with an anthropomorphic abdomen phantom under different imaging conditions, and isodose curves were constructed. Operator exposure was shown to increase with patient dose-area product as the imaging field of view (FOV) is changed, with the highest scatter levels occurring with an intermediate-sized FOV. Use of copper spectral beam filtration was found to result in decreased operator exposure, whereas use of wedge-shaped equalization filters was found to increase exposure. The effect of increasing patient abdomen thickness was simulated by surrounding the phantom with plastic bolus material. Increasing the thickness by 5 cm resulted in a doubling of exposure at the operator's waist. Exposure to the operator's upper body was significantly reduced when the FOV was positioned on the far side of the patient. Operator exposure can be maintained at an acceptable level by taking these variables into consideration and incorporating the suggested dose reduction techniques into routine practice to the greatest extent possible.

Use of minimally invasive surgical techniques in the management of thoracolumbar trauma: current concepts

STUDY DESIGN

Literature review and expert opinion.

OBJECTIVE

To provide an overview of the current concepts of minimally invasive surgical (MIS) techniques for the management of thoracolumbar (TL) spinal trauma.

SUMMARY OF BACKGROUND DATA

Current surgical treatment of thoracolumbar trauma typically involves open placement of spinal instrumentation with fusion. Conventional open spinal exposures can be associated with significant muscle morbidity that can lead to subsequent paraspinal muscular atrophy, scarring, decreased extensor strength and endurance, as well as pain. This approach-related morbidity is the main impetus for application MIS techniques to spinal procedures including trauma.

METHODS

A review of the relevant English literature was performed.

RESULTS

The current rationale, clinical applications, outcomes, and limitation of MIS management of TL injuries are summarized.

CONCLUSION

The application of MIS techniques to spinal trauma is theoretically sound. However, the indications and technology are currently in evolution. Although very limited information is available, the results of current MIS techniques for the management of TL trauma are encouraging.

The feasibility of color Doppler ultrasonography for caudal epidural steroid injection

Although it entails a radiation hazard risk, the use of fluoroscopy during caudal epidural steroid injection has increased to help place the medication more accurately and allowed physicians to maximize the procedure's therapeutic success rate. To investigate the feasibility of using real-time high resolution ultrasonography for guiding the epidural needle into the caudal epidural space and to confirm any vascular intake of medication, we performed color Doppler ultrasonography while medication was being injected into the caudal epidural space of 53 patients with low back pain and sciatica. We defined the injection as being successful if unidirectional flow (observed as one dominant color) of the solution was observed with color Doppler ultrasonography through the epidural space beneath the sacrococcygeal ligament, with no flows being observed in other directions (observed as multiple colors). The correct placement of the medication was then confirmed by fluoroscopy. In 52 of the 53 subjects, the medications were successfully injected into the caudal epidural space with ultrasonography assistance. In fluoroscopy, of these 52 patients, 50 revealed correct placement of the medicine into the epidural space. In conclusion, ultrasonography may be a reliable imaging modality for caudal epidural steroid injection, and its several advantages such as its convenience and the lack of a radiation hazard, make it preferable to fluoroscopy.