Testing of an innovative person tracking system for real time dosimetry in interventional radiology

SCK•CEN Mentor

Lombardo Pasquale, plombard@sckcen.be, +32 (0)14 33 28 54

Expert group

Research in Dosimetric Applications

SCK•CEN Co-mentor

Abdelrahman Mahmoud , mabdelra@sckcen.be , +32 (0)14 33 27 53

Introduction

Interventional radiologists have the highest exposure to radiation among medical staff working with X‑ray techniques [1]. In recent years, the dramatic improvements of the imaging devices allowed to increase the number of clinical tasks that can be performed in interventional radiology. As a result, the number of procedures continues to rise. The occupational dose is currently determined by means of physical dosimeters. Doses to the trunk are monitored routinely, but this sole quantity is often not indicative of the doses delivered to other parts of the body. In fact, in interventional radiology the tissues that may be exposed to higher doses are those in the head and in the hands. The dose to the hands is a matter of concern because of the need for the operator to be close to the X-ray field to carry out manipulations, and the possibility of higher doses from poor practice if the hands are exposed to the primary beam [2]. However, monitoring those body parts would require the staff to wear several (special) dosimeters. This is not practical nor ergonomic to the operators; furthermore, the sensitivity of such dosimeters would be greatly affected by the angular and energy responses. In line with the current trends and necessity for real-time dose monitoring, we are working towards an innovative approach to determine occupational exposures. Instead of using dosimeters, our methodology is based on computational simulations.

[1] International Commission on Radiological Protection. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication 85. Annals of the ICRP 30(2) 2000

[2] Donadille L, Carinou E, Ginjaume M, Jankowski J, Rimpler A, Sans Merce M, et al. An overview of the use of extremity dosemeters in some European countries for medical applications. Rad Prot Dosim 2008;131:62–6

Objective

The aim of this research is to calculate doses to workers instead of measuring them. For this, the spatial radiation field, including energy and angular distribution, needs to be known and can be inferred from information about the tube angulation, operator position and beam collimation but also from some area monitors in the surroundings. The real movement of the operators can be monitored in real-time using motion tracking cameras, like Time-of-Flight (TOF) cameras, and flexible computational phantoms representing the workers anatomy. The phantom will be positioned using the tracking information from the TOF camera. Finally, all this input data should be converted to Monte-Carlo input by means of an in-house conversion program, allowing to calculate the doses to the staff.

The proposed internship is dealing with the part of testing the application in interventional radiology exposure scenario. A tracking program using ToF cameras was developed for recording the position and the posture of the medical staff. The positions in which interventional operators stand relative to the X-ray beam are largely determined by the procedures performed. The tracking software will be used to evaluate the positions in which interventional operators stand relative to the X-ray beam as well as the hands and legs relative positions.

The goal of the internship is to do a series of tests for operators monitoring during interventional procedures. Next step is analyzing the recorded movements and establishing a database of selected operator poses and positions to be used to position a flexible computational phantom in the Monte-Carlo simulations. The final goal is to perform Monte-Carlo simulations using MCNP to calculate dose received by the operators and to establish criteria for the initiation of the calculation. Those criteria are mainly depending on operator’s poses relative to the X-ray beam which result in considerable dose and also on the variation of the scattered radiation field around the patient. For this, source input model in MCNP will be investigated for different beam settings evaluating different variables. It is foreseen that optimization of the simulation running time will be studied.

The minimum diploma level of the candidate needs to be

Professional bachelor , Academic bachelor

The candidate needs to have a background in

Physics , the knowledge of Monte Carlo methods and computer programming (c++) is a plus

Estimated duration

120-180