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.

Evaluation of scattered radiation dose received by medical staff during uterine artery embolization in the operating room.

BACKGROUND: The air kerma radiation doses have gained much attention since the operating room interventional radiology is a place where medical staff are exposed to a fluoroscopy environment and gain a cumulative dose during the uterine artery embolization procedure. OBJECTIVE: We aimed to evaluate the radiation dose received by medical staff by applying a flat X-ray machine in the surgical room during uterine artery embolization. METHODS: An ATOM humanoid model was laid on the operating table and simulated a patient. The scattered radiation dose received by the radiologist, anesthetist and radiologic technologist was evaluated. The scintillation detector was adopted. The measurement points were 50 cm, 100 cm and 150 cm above the floor, representing the limbs, abdomen and thyroid level, respectively. We compared the X-rays under different tube voltages of 70, 80, and 90, respectively and frames per second (FPS) of 30, 15, and 7.5, respectively. We configured the dose level per pulse of 40 nGy with a fixed detector. RESULTS: In Section 1, when the tube voltage was 70 kVp and 7.5 FPS, the average radiation doses of limbs, abdomen and thyroid level was 0.48, 1.3 and 1.9 µSv/min respectively. When the tube voltage was 80 kVp and the fluoroscopy decreases from 30 FPS to 7.5 FPS, 58% of the radiation dose was reduced. When the tube voltage was 90 kVp, the radiation dose in the lead garment increased 31-177% in comparison to when the tube voltage was 80 kVp. Sections 2 and 3 were far away from the central ray, so the highest radiation dose 100 cm above the floor were 0.05 and 0.02 µSv/min. CONCLUSIONS: Lead garment can effectively reduce medical staff from occupational doses with an average attenuation rate of 90%. 80 kVp was most commonly used. Fluoroscopy 7.5 FPS was used 100 cm above the floor in A section and the lowest radiation dose was 1.33 µSv/min. The operator should decrease the duration of X-rays or adopt suspended lead shielding to decrease the radiation dose received by the operator. When kVp increases, the penetration increases. Decreasing FPS cannot decrease occupational doses of medical staff.

Effective dose for multiple and repeated radiation examinations in donors and recipients of adult-to-adult living donor liver transplants at a single center.

PURPOSE: To evaluate the effective doses received by donors and recipients, identify effective dose contributions, and make risk assessments. MATERIALS AND METHODS: It was a retrospective study. 100 Donors and 100 recipients were enrolled with an operative day from March 2016 to August 2017. The dose was analyzed for all radiation-related examinations over a period of 2 years, 1 year before and 1 year after the LDLT procedure. The effective doses of plain X-rays, CT, fluoroscopy, and nuclear medicine per patient were simulated by a Monte Carlo software, evaluated by the dose-length product conversion factors, evaluated by the dose-area product conversion factors, and evaluated by the activity conversion factors, respectively. The risks of radiation-induced cancer were assessed on the basis of the ICRP risk model. RESULTS: The median effective doses were 71 (range: 30-186) mSv for donors and 147 (32-423) mSv for recipients. The radiation examinations were mainly performed in the last three months of preoperative period to first month of postoperative period for recipients and donors. The HCC recipients received a higher effective dose, 195 (64-423) mSv, than those with other indications. The median radiation-induced cancer risk was 0.38 % in male and 0.48 % in female donors and was 0.50 % in male and 0.58 % in female recipients. CONCLUSION: Donors and recipients received a large effective dose, mainly from the CT scans. To reduce effective doses should be included in future challenges in some living donor liver transplants centers that often use CT examinations.

Personal Exposure Prescription Method Reduces Dose in Radiography.

PURPOSE: To evaluate the effectiveness of an automatic, personalized exposure prescription method designed to reduce radiation dose during radiography examinations. METHODS: Using standard imaging parameters of average-sized patients, the authors measured individual body-part thicknesses or imaging regions of 116 patients (69 men, 47 women) and calculated each patient's exposure amount according to the thickness of the part or region. The data were used to develop each patient's personalized exposure prescription. Using the personalized exposure prescriptions, authors acquired chest images of the patients on a Carestream DRX-Revolution mobile digital radiography system. RESULTS: All images acquired using the personalized exposure prescription method were satisfactory for diagnosis; exposure indexes were above 1300, a figure deemed acceptable for diagnosis by the manufacturer. The personalized exposure method reduced the amount of radiation each patient received. DISCUSSION: Variation of tube voltage alone can control patients' exposure levels; however, using the personalized exposure prescription method eliminates the need to use automatic exposure controls. CONCLUSION: The personalized exposure prescription method is an effective tool for reducing radiation to patients during radiography as well as for eliminating dose creep.

Scattered radiation doses absorbed by technicians at different distances from X-ray exposure: Experiments on prosthesis.

UNLABELLED: This work aimed to investigate the spatial distribution of scattered radiation doses induced by exposure to the portable X-ray, the C-arm machine, and to simulate the radiologist without a shield of lead clothing, radiation doses absorbed by medical staff at 2 m from the central exposure point. MATERIAL AND METHOD: With the adoption of the Rando Phantom, several frequently X-rayed body parts were exposed to X-ray radiation, and the scattered radiation doses were measured by ionization chamber dosimeters at various angles from the patient. Assuming that the central point of the X-ray was located at the belly button, five detection points were distributed in the operation room at 1 m above the ground and 1-2 m from the central point horizontally. RESULTS: The radiation dose measured at point B was the lowest, and the scattered radiation dose absorbed by the prosthesis from the X-ray's vertical projection was 0.07 ±0.03 µGy, which was less than the background radiation levels. The Fluke biomedical model 660-5DE (400 cc) and 660-3DE (4 cc) ion chambers were used to detect air dose at a distance of approximately two meters from the central point. The AP projection radiation doses at point B was the lowest (0.07±0.03 µGy) and the radiation doses at point D was the highest (0.26±0.08 µGy) .Only taking the vertical projection into account, the radiation doses at point B was the lowest (0.52 µGy), and the radiation doses at point E was the highest (4 µGy).The PA projection radiation at point B was the lowest (0.36 µGy) and the radiation doses at point E was the highest(2.77 µGy), occupying 10-32% of the maximum doses. The maximum dose in five directions was nine times to the minimum dose. When the PX and the C-arm machine were used, the radiation doses at a distance of 2 m were attenuated to the background radiation level. The radiologist without a lead shield should stand at point B of patient's feet. Accordingly, teaching materials on radiation safety for radiological interns and clinical technicians were formulated.