Protected and Unprotected Radiation Exposure to the Eye Lens During Endovascular Procedures in Hybrid Operating Rooms.

OBJECTIVE: Radiation cataract has been observed at lower doses than previously thought, therefore the annual limit for equivalent dose to the eye lens has been reduced from 150 to 20 mSv. This study evaluated radiation exposure to the eye lens of operators working in a hybrid operating room before and after implementation of a dose reduction program. METHODS: From April to October 2019, radiation exposure to the first operator was measured during all consecutive endovascular procedures performed in the hybrid operating room using BeOSL Hp(3) eye lens dosimeters placed both outside and behind the lead glasses (0.75 mm lead equivalent). Measured values were compared with data from a historic control group from the same hospital before implementation of the dose reduction program. RESULTS: A total of 181 consecutive patients underwent an endovascular procedure in the hybrid operating room. The median unprotected eye lens dose (outside lead glasses) of the main operator was 0.049 mSv for endovascular aortic repair (EVAR) (n = 30), 0.042 mSv for thoracic endovascular aortic repair (TEVAR) (n = 23), 0.175 mSv for complex aortic fenestrated or branched endovascular procedures (F/BEVAR; n = 15), and 0.042 mSv for peripheral interventions (n = 80). Compared with the control period, EVAR had 75% lower, TEVAR 79% lower, and F/BEVAR 55% lower radiation exposure to the unprotected eye lens of the first operator. The lead glasses led to a median reduction in the exposure to the eye lens by a factor of 3.4. CONCLUSION: The implementation of a dose reduction program led to a relevant reduction in radiation exposure to the head and eye lens of the first operator in endovascular procedures. With optimum radiation protection measures, including a ceiling mounted shield and lead glasses, more than 440 EVARs, 280 TEVARs, or 128 FEVARs could be performed per year before the dose limit for the eye lens of 20 mSv was reached.

Staff dose evaluation by application of radiation protection during endoscopic retrograde cholangiopancreatography (ERCP) procedures performed with a mobile C-arm.

BACKGROUND: The radiation dose to staff performing endoscopic retrograde cholangiopancreatography (ERCP) is not negligible. PURPOSE: To evaluate the shielding effect of a table-suspended lower-body radiation shield for the positions in the room occupied by the operator, assisting nurse, and anesthesiologist, used during ERCP procedures with a mobile C-arm. MATERIAL AND METHODS: Eye lens dose, whole body dose, and extremity dose were measured with and without a table-suspended lower-body radiation shield in a phantom model and in clinical routine work. The effect of the shield was evaluated for each scenario and compared, and a projection was made for when shielding should be required from a regulatory point of view. RESULTS: In the phantom measurements, the shield provided significant shielding effects on the body and lower extremities for the operator but no significant shielding of the eye lens. The shielding effect for the assisting nurse was limited to the lower extremity. The clinical measurements yielded the same general result as the phantom measurements, with the major difference that the shield provided no significant reduction in the whole-body dose to the operator. CONCLUSION: The table-suspended shield has a significant shielding effect for the lower extremities of the operator and assisting nurse. For annual dose-area product values >300,000 cGycm2, the protection of the operator should be reinforced with a ceiling-suspended shield to avoid doses to the eye lens and body in excess of regulatory dose restrictions.

Simulation of Hp(0,07) beta and photon response of a BeOSL finger ring dosemeter.

Simulation of a dosemeter's energy and angular response lowers development cost and time. To support development of a new beta sensitive dosemeter we simulate both the dosemeter and the skin dose in a rod phantom as there are no fluence to dose conversion coefficients in the ICRU Report 47 for electrons. Published spectra for BSS2, N-Series and S-Cs and S-Co were used to define sources, with CAD models used to define the simulation geometry. Simulation tools were validated with experimental beta and photon responses available for the BeOSL photon ring. The developed toolchain was then used to simulate several iterations of a beta sensitive detector element inside a beta ring holder, with the goal to minimise the need for repeated prototype fabrication and characterisation. Simulation results for the final design were compared to measurements on 3D printed prototypes with all radiation qualities, except 90Sr/90Y 0°, falling within measurement uncertainty.

Free-Hand MIS TLIF without 3D Navigation-How to Achieve Low Radiation Exposure for Both Surgeon and Patient.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) is one of the most frequently performed spinal fusion techniques, and this minimally invasive (MIS) approach has advantages over the traditional open approach. A drawback is the higher radiation exposure for the surgeon when conventional fluoroscopy (2D-fluoroscopy) is used. While computer-assisted navigation (CAN) reduce the surgeon's radiation exposure, the patient's exposure is higher. When we investigated 2D-fluoroscopically guided and 3D-navigated MIS TLIF in a randomized controlled trial, we detected low radiation doses for both the surgeon and the patient in the 2D-fluoroscopy group. Therefore, we extended the dataset, and herein, we report the radiation-sparing surgical technique of 2D-fluoroscopy-guided MIS TLIF. METHODS: Monosegmental and bisegmental MIS TLIF was performed on 24 patients in adherence to advanced radiation protection principles and a radiation-sparing surgical protocol. Dedicated dosemeters recorded patient and surgeon radiation exposure. For safety assessment, pedicle screw accuracy was graded according to the Gertzbein-Robbins classification. RESULTS: In total, 99 of 102 (97.1%) pedicle screws were correctly positioned (Gertzbein grade A/B). No breach caused neurological symptoms or necessitated revision surgery. The effective radiation dose to the surgeon was 41 ± 12 µSv per segment. Fluoroscopy time was 64 ± 34 s and 75 ± 43 radiographic images per segment were performed. Patient radiation doses at the neck, chest, and umbilical area were 65 ± 40, 123 ± 116, and 823 ± 862 µSv per segment, respectively. CONCLUSIONS: Using a dedicated radiation-sparing free-hand technique, 2D-fluoroscopy-guided MIS TLIF is successfully achievable with low radiation exposure to both the surgeon and the patient. With this technique, the maximum annual radiation exposure to the surgeon will not be exceeded, even with workday use.

The Impact of Implementing a Radiation-Sparing Protocol for Percutaneous Kyphoplasty-A Prospective Dosemetric Study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: The purpose of this prospective study was to evaluate a protocol for radiation-sparing kyphoplasty by assessing dosemetrically recorded radiation exposures to both patient and surgeon. METHODS: This prospective clinical study examines the radiation exposure to patient and surgeon during single-level kyphoplasty in 32 thoracolumbar osteoporotic vertebral body fractures (12 OF 2, 9 OF 3, 11 OF 4 types) using a radiation aware surgical protocol between May 2017 and November 2019. The radiation exposure was measured at different locations using film, eye lens and ring dosemeters. Dose values are reported under consideration of lower detection limits of each dosemeter type. RESULTS: A high proportion of dosemeter readings was below the lower detection limits, especially for the surgeon (>90%). Radiation exposure to the surgeon was highest at the unprotected thyroid gland (0.053 ± 0.047 mSv), however only slightly above the lower detection limit of dosemeters (0.044 mSv). Radiation exposure to the patient was highest at the chest (0.349 ± 0.414 mSv) and the gonad (0.186 ± 0.262 mSv). Fluoroscopy time, dose area product and number of fluoroscopic images were 46.0 ± 17.9 sec, 124 ± 109 cGy×cm2, and 35 ± 13 per kyphoplasty, respectively. Back pain significantly improved from 6.8 ± 1.6 to 2.5 ± 1.7 on the numeric rating scale on the first postoperative day (P < 0.0001). CONCLUSIONS: The implementation of a strict intraoperative radiation protection protocol allows for safely performed kyphoplasty with ultra-low radiation exposure for the patient and surgeon without exceeding the annual occupational dose limits. TRIAL REGISTRATION: The study was registered in the German Clinical Trials Register (DRKS00011908, registration date 16/05/2017).

Patient radiation exposure from intraoperative computed tomography in spinal surgery.

Intraoperative CT imaging is becoming increasingly used, but often little attention is paid to the underlying radiation exposure to the patient. This work showed that the dosimetrically assessed radiation exposure for cervical and lumbar 3D scans with an intraoperative CT is considerably higher than with a 3D C-arm. Therefore, proper selection of the intraoperative 3D imaging system is essential, and further technological developments and dose-saving protocols are warranted to further reduce patient radiation exposure.

Radiation protection measures to reduce the eye lens dose in spinal surgery.

The annual limit value for the eye lens dose for occupationally exposed personnel has recently been considerably reduced from 150mSv to 20mSv. We have therefore re-evaluated the effectiveness of radiation protection measures (lead glass goggles, mobile radiation shielding wall and distance to the radiation source) in an experimental setting to provide spinal surgeons with clearly understandable radiation dose data for their daily work.

Radiation Exposure in Minimally Invasive Lumbar Fusion Surgery: A Randomized Controlled Trial Comparing Conventional Fluoroscopy and 3D Fluoroscopy-based Navigation.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: The aim of this study was to compare the dosemetrically determined radiation exposure of surgeon and patient during minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) using conventional 2D fluoroscopy (FLUORO) or 3D fluoroscopy-based navigation (NAV). SUMMARY OF BACKGROUND DATA: MIS TLIF was shown to exhibit higher radiation exposures compared to open techniques. In particular, the routinely exposed surgeon encounters the risks of increased radiation doses. With the additional use of intraoperative 3D navigation, major steps of the operation can be performed without exposing the operating room staff to ionizing radiation. METHODS: Forty-four patients undergoing monosegmental MIS TLIF were randomized into the two intraoperative imaging technique groups (FLUORO or NAV). The primary endpoint was the radiation exposure of the surgeon; the secondary endpoints were the radiation exposure of the patient and C-arm readings. RESULTS: After exclusion of three patients, 41 patients were analyzed. In general, the average radiation exposure of the surgeon was lower in the NAV group without being statistically significant. The radiation exposure of the patient was significantly higher in the NAV group at all dosemeter sites. The average fluoroscopy time was 63 ±â€Š36 versus 109 ±â€Š31 sec (FLUORO versus NAV group, P < 0.001). CONCLUSION: The additional use of intraoperative 3D fluoroscopy-based navigation compared to conventional 2D fluoroscopy alone showed a nonsignificant reduction of the radiation exposure of the surgeon in monosegmental MIS TLIF, while increasing the radiation exposure of the patient. LEVEL OF EVIDENCE: 1.

Radiation Exposure to Scrub Nurse, Assistant Surgeon, and Anesthetist in Minimally Invasive Spinal Fusion Surgery Comparing 2D Conventional Fluoroscopy With 3D Fluoroscopy-based Navigation: A Randomized Controlled Trial.

STUDY DESIGN: A randomized controlled trial. OBJECTIVE: To compare the radiation exposure with the scrub nurse, assistant surgeon, and anesthetist during minimally invasive transforaminal lumbar interbody fusion using conventional 2-dimensional (2D) fluoroscopy or 3D fluoroscopy-based navigation. SUMMARY OF BACKGROUND DATA: Minimally invasive spinal fusion techniques are related to higher radiation exposures compared with open techniques. Especially the routinely exposed surgical staff faces the risks of increased radiation exposure. METHODS: In total, 41 patients with planned monosegmental minimally invasive transforaminal lumbar interbody fusion were randomized into the intraoperative imaging techniques 2D fluoroscopy or 3D navigation. Eye lens and film dosemeters were attached to defined locations of the scrub nurse, assistant surgeon, and anesthetist. Mann-Whitney U and Wilcoxon-matched pairs signed-rank test were used to compare dosemeter readings. This study was registered with the German Clinical Trials Register (DRKS00004514). RESULTS: The radiation exposure per surgery was low for the scrub nurse, assistant surgeon, and anesthetist in both the 2D fluoroscopy and 3D navigation groups. The maximum average value of 0.057±0.031 mSv was measured on the unprotected chest of the assistant surgeon and was thus slightly above the lower detection limit of the dosemeters (0.044 mSv). The annual occupational dose limit would be exceeded at the earliest after 571 operations for the unprotected eye lens of the assistant surgeon. CONCLUSIONS: Minimally invasive lumbar fusion surgery is possible with comparatively low radiation exposure to the assisting operating room personnel without exceeding the annual maximum occupational radiation exposure. However, there is no definite dose value below which ionizing radiation poses no risk. Consequently, radiation sparing work routines should be strictly followed.

Assessing the level of radiation experienced by anesthesiologists during transfemoral Transcatheter Aortic Valve Implantation and protection by a lead cap.

OBJECTIVE: Transfemoral Transcatheter Aortic Valve Implantation (TAVI) has become a standard therapy for patients with aortic valve stenosis. Fluoroscopic imaging is essential for TAVI with the anesthesiologist's workplace close to patient's head side. While the use of lead-caps has been shown to be useful for interventional cardiologists, data are lacking for anesthesiologists. METHODS: A protective cap with a 0.35 lead-equivalent was worn on 15 working days by one anesthesiologist. Six detectors (three outside, three inside) were analyzed to determine the reduction of radiation. Literature search was conducted between April and October 2018. RESULTS: In the observational period, 32 TAVI procedures were conducted. A maximum radiation dose of 0.55 mSv was detected by the dosimeters at the outside of the cap. The dosimeters inside the cap, in contrast, displayed a constant radiation dose of 0.08 mSv. CONCLUSION: The anesthesiologist's head is exposed to significant radiation during TAVI and it can be protected by wearing a lead-cap.