Congress:
EuroSafe Imaging 2016
Keywords:
Action 7 - Medical radiation protection research: MELODI, EURAMED, Action 3 - Optimisation, diagnostic reference levels, image quality, Action 2 - Clinical diagnostic reference levels (DRLs), Action 9 - Facilitation of research in advanced topics of radiation protection
Authors:
M. Poli, C. Bracco, D. Campanella, M. Stasi, D. Regge
DOI:
10.1594/esi2016/ESI-0039
Background/Introduction
Computed tomography (CT) is a powerful imaging technique that provides high-contrast images and good spatial and temporal resolution [1],
but it involves higher radiation doses than other radiological investigations.
In the last 40 years CT systems have increasingly been used in clinical practice,
with growing concerns about patient radiation protection,
in particular for screening exams [2] or pediatric acquisitions [3,4].
Especially for these exams the risk to benefit ratio should be deeply evaluated,
according to the ALARA principle [5].
Different studies have focused on dose reduction strategies in CT exams [2,
6],
including automatic exposure control [7],
tube voltage lowering [8] and development of new reconstruction algorithms [9,10].
Oncological patients in the radiological unit at Candiolo Cancer Institute FPO-IRCCS undergo multiple follow up CT scans,
resulting in high cumulative radiation exposures.
Three years experience with a new CT Siemens Somatom Definition Flash is here analyzed and presented.
In particular,
the implementation of SAFIRE low-dose CT protocol and the results in terms of dose (D) reduction are shown.
New protocols were clinically implemented only after a clinical validation with which the physician confirmed no loose of diagnostic quality.
High relevance is given to the transition between protocols based on filtered back projection (FBP) reconstruction to low-dose protocols based on SAFIRE reconstruction.
The large number of kernels available and the 5 different SAFIRE strength levels make this transition hard: the choice of the filter (kernel and strength level) to be exploited for dose reduction,
preserving the initial image quality (IQ),
is still a problem.