Research Presentation Session: Physics in Medical Imaging
RPS 1013 - Computed tomography (CT)
Lectures
RPS 1013-1 - Introduction
01:21Konstantinos Perisinakis, Boris Brkljačić.mp4
RPS 1013-2 - Commissioning of a whole-body photon counting spectral CT scanner - physico-technical tests
11:23Hilde Bosmans.mp4
RPS 1013-4 - Task-based study of dose reduction using different kernels and model-based iterative reconstruction levels for low-contrast lesion
07:26Denise Curto.mp4
RPS 1013-5 - Evaluation of the impact of ICRP 135 calculation methodology on LDRL deriving from a large cohort of oncology patients undergoing three phases multiregional CT
09:10Agnieszka Kuchcinska.mp4
RPS 1013-6 - Task-based study of detectability for dose reduction using different model-based iterative reconstruction for three computed tomography systems
08:25Gaia Muti.mp4
RPS 1013-7 - Empirical scatter correction (ESC) - a universal scatter reduction method for cone-beam CT (CBCT) without prior knowledge
08:18Philip Trapp.mp4
RPS 1013-8 - Multicentric comparative study of computed tomography dose indicators using an "in vivo" optical fiber detection system
09:22Christian Popotte
Author Block: C. Devic1, M. Munier1, F. Pilleul2, H. Rousseau3, C. Popotte1; 1Entzheim/FR, 2Lyon/FR, 3Toulouse/FR
Purpose or Learning Objective: Real-time personalised dosimetry specific of both the equipment and the patient may lead to a paradigm shift in computed tomography dosimetry. The aim of this work is to compare dose index measured by a new real-time in vivo dosimeter under clinical CT conditions and estimated dose index displayed by scanners, and to detect any anomalies during CT procedures. Specific cases are presented.
Methods or Background: A multicentric study was conducted in 4 French medical centers and 5 CT scans from 3 different manufacturers. An innovative detector, based on a scintillating optical fiber (IVIscan®,FIBERMETRIX,France) has been used routinely to measure CTDI and DLP. The IVIscan® system was also used to determine the z-axis CTDI mapping and distribution for procedures including those involving several acquisitions.
Results or Findings: Dose indexes were generally consistent with those displayed by the scanners independently of the manufacturer, which validates the use of the IVIscan® device under clinical conditions. However, large differences have been observed for some examinations and allowed us to detect scanner modulation failures and poor patient positioning leading to overdoses up to +300%. In addition, CTDI mapping allows a better assessment of the dose actually delivered during a CT procedure compared to the average CTDI usually used especially for procedures with several acquisitions.
Conclusion: Thanks to reliable real-time measured dose indexes and an innovative CTDI mapping system, IVIscan® is an independent dosimetric monitoring tool which allows to detect dose heterogeneities and identify possible malfunctions of the CT device or unusual practices.
Limitations: Headrest head CT could not be integrated in this study.
Ethics committee approval: The data used in this study do not require ethics committee approval.
Funding for this study: This study is part of the development of the material used and did not require specific research funding.