Radiation protection

The basics of radiation protection in theatre for the patient follow principles similar to those used in plain-film imaging. These include ensuring positive identification of the patient, justification of radiation exposure, avoiding irradiation of pregnant patients wherever possible, minimization and optimization of exposures performed (ALARP principle), protection of all staff involved, and recording and monitoring of all exposures performed. This chapter covers the aspects of protection from radiation for the patient, surgical team, and the radiographer when performing imaging during surgical interventions. Topics covered include the use of beam collimation, minimizing exposure to the patient and team, radiation scatter, and the use and requirements of radiation shielding such as lead aprons and barriers.

Scatter analysis and correction for ultrafast X-ray tomography

Ultrafast X-ray computed tomography (CT) is an imaging technique with high potential for the investigation of the hydrodynamics in multiphase flows. For correct determination of the phase distribution of such flows, a high accuracy of the reconstructed image data is essential. In X-ray CT, radiation scatter may cause disturbing artefacts. As the scattering is not considered in standard reconstruction algorithms, additional methods are necessary to correct the detector readings or to prevent the detection of scattered photons. In this paper, we present an analysis of the scattering background for the ultrafast X-ray CT imaging system ROFEX at the Helmholtz-Zentrum Dresden-Rossendorf and propose a correction technique based on collimation and deterministic simulation of first-order scattering.

Effect of C-Arm Year Model on Radiation Scatter

Since the 1980’s C-arm fluoroscopy has been an integral part of orthopaedic trauma surgery. The advancement in C-arm technology has resulted in different generations of C-arms co-existing in the operating rooms. The purpose of this study was to compare the radiation scatter patterns of different generation C-arms. Three generation of C-arms were tested: GE OEC 9800 Plus (1999/2000), Siemens Arcadis Orbic 3D (2004), Philips BV Pulsera 2.3 (2008). Radiation scatter was measured using six real-time dosimetry badges set up on either side of the surgical table (Mizuho OSI, flat-top). Distance of C-arm was normalized at 20 in. and 10 in. from Image Intensifier. Each device was set to the automatic brightness control (ABC) setting. A phantom limb was irradiated for 120 s and radiation scatter was summed for both AP and lateral positions. At their typical operating room settings there was a reduction in radiation scatter using the newer generation C-arms. Results for total radiation, normalized to Philips, are as follows: Philips 1 (100%), GE 2.4 (240%), and Siemens 1.4 (140%). Newer generation C-arms can be expected to generate lower radiation scatter. Special care should be taken to attempt a lower dose setting, especially when utilizing older generation C-arms to minimize radiation scatter to practitioner.

Operating room radiation exposure in cone beam computed tomography–based, image-guided spinal surgery

Object Surgeon and operating room (OR) staff radiation exposure during spinal surgery is a concern, especially with the increasing use of multiplanar fluoroscopy in minimally invasive spinal surgery procedures. Cone beam computed tomography (cbCT)–based, 3D image guidance does not involve the use of active fluoroscopy during instrumentation placement and therefore decreases radiation exposure for the surgeon and OR staff during spinal fusion procedures. However, the radiation scatter of a cbCT device can be similar to that of a standard 64-slice CT scanner and thus could expose the surgeon and OR staff to radiation during image acquisition. The purpose of the present study was to measure radiation exposure at several unshielded locations in the OR when using cbCT in conjunction with 3D image-guided spinal surgery in 25 spinal surgery cases. Methods Five unshielded badge dosimeters were placed at set locations in the OR during 25 spinal surgery cases in which cbCT-based, 3D image guidance was used. The cbCT device (O-ARM) was used in conjunction with the Stealth S7 image-guided platform. The radiology department analyzed the badge dosimeters after completion of the last case. Results Fifty high-definition O-ARM spins were performed in 25 patients for spinal registration and to check instrumentation placement. Image-guided placement of 124 screws from C-2 to the ileum was accomplished without complication. Badge dosimetry analysis revealed minimal radiation exposure for the badges 6 feet from the gantry in the area of the anesthesiology equipment, as well as for the badges located 10–13 feet from the gantry on each side of the room (mean 0.7–3.6 mrem/spin). The greatest radiation exposure occurred on the badge attached to the OR table within the gantry (mean 176.9 mrem/spin), as well as on the control panel adjacent to the gantry (mean 128.0 mrem/spin). Conclusions Radiation scatter from the O-ARM was minimal at various distances outside of and not adjacent to the gantry. Although the average radiation exposure at these locations was low, an earlier study, undertaken in a similar fashion, revealed no radiation exposure when the surgeon stood behind a lead shield. This simple precaution can eliminate the small amount of radiation exposure to OR staff in cases in which the O-ARM is used.

Radiation Dose Reduction during Radial Cardiac Catheterization: Evaluation of a Dedicated Radial Angiography Absorption Shielding Drape

Objectives. Radiation scatter protection shield drapes have been designed with the goal of decreasing radiation dose to the operators during transfemoral catheterization. We sought to investigate the impact on operator radiation exposure of various shielding drapes specifically designed for the radial approach. Background. Radial access for cardiac catheterization has increased due to improved patient comfort and decreased bleeding complications. There are concerns for increased radiation exposure to patients and operators. Methods. Radiation doses to a simulated operator were measured with a RadCal Dosimeter in the cardiac catheterization laboratory. The mock patient was a 97.5 kg fission product phantom. Three lead-free drape designs were studied. The drapes were placed just proximal to the right wrist and extended medially to phantom’s trunk. Simulated diagnostic coronary angiography included 6 minutes of fluoroscopy time and 32 seconds of cineangiography time at 4 standard angulated views (8 s each), both 15 frames/s. ANOVA with Bonferroni correction was used for statistical analysis. Results. All drape designs led to substantial reductions in operator radiation exposure compared to control (P<0.0001). The greatest decrease in radiation exposure (72%) was with the L-shaped design. Conclusions. Dedicated radial shielding drapes decrease radiation exposure to the operator by up to 72% during simulated cardiac catheterization.