Aims and objectives
Computed tomography (CT) examinations are increasing not only for their clinical value but also because of the widespread availability of high-performance technology.
Modern scanners display values of computed tomography dose index (CTDI) and dose length product (DLP) for each examination.
The effective dose from a single CT examination can therefore be well monitored and controlled as required by EU regulations on diagnostic reference levels.
On the contrary,
the cumulative effective dose...
Methods and materials
A statistical analysis was performed on the picture archive communication system (PACS) shared by five hospitals of the same district to evaluate the incidence of recurrent CT scans.
The inter-hospital PACS collects data from ten CT scanners,
which are employed in a wide range of clinical situations,
including emergency and paediatric radiology.
Patients who underwent more than two CT examinations in seven months were selected and included in different age ranges.
The analysis was focused on...
The total number of CT examinations taken into analysis was about 18.000.
Patients undergone to more than two CT scans were 1.604 (about 9%). The number of CT studies per patient was distributed as follows: 83% up to 5; 14.8 % between 6 and 10; 2.2% more than 10.
Figure 1 shows an overall plot (head,
chest and abdomen CT) of the incidence of recurrent CTs vs age ranges.Figures 2-4 show in detail the number of observed cases. The highest incidence of recurrent CTs was observed for the head...
This study shows a significant recurrence of CT examinations and considerable levels of exposures.
A standard risk estimation based on the observed effective doses highlighted the benefit of an inter-hospital dosimetric repository to monitor patients cumulative doses.
The knowledge of cumulative doses can support clinicians in the risk-benefit decision.
1 “Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog” FA Mettler,
TT Yoshizumi Mahesh, Radiology (2008) 1: 254-263 2 “Age-specific Effective Doses for Pediatric MSCT Examinations at a Large Children’s Hospital using DLP Conversion Coefficients: a Simple Estimation Method” KE Thomas and B Wang, Pediatr Radiol (2008) 38:645–656 3 “European Guidelines on Quality Criteria for Computed Tomography” EUR 16262 4 BEIR VII Health Risks from Exposure to Low Levels of...