Adult and Paediatric Patient Radiation Doses From Multidetector CT Scans: a National Survey

CT imaging is rapidly growing and now represents an indispensable medical procedure for many clinical conditions. The widespread availability and expanding use of multidetector CT (MSCT) due to its high performance and very short acquisition times, has resulted in an increase in both frequency of procedures and level of patient exposures from CT scan examinations, but issues related to radiation, including potential risks, have been relatively neglected. Particular attention should be given to CT scans in children, as they represent about 10% of all the X-ray studies performed on them, accounting for about 75% of the total dose administered. CT in children should be performed only when absolutely necessary as their longer life expectation and sensitivity to X-ray radiations may increase the risk of causing radiation-induced neoplasm's in later years.

According to the 2000 report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) the frequency of CT examinations in countries with high healthcare levels has increased by a factor of 8; with the mean effective dose increasing from 1,3 mSv in the 1970s to 8,8 mSv per year per 1000 persons in the early 1990s. In Switzerland, Germany and United Kingdom the increases in the number of reported CT examinations ranged between 39% and 70% over just the period 1998-2002. The 2000 ISTAT report's estimated that 1479 CT apparatus were installed in Italy performing a total of 3.327.750 CT examinations [3]. Considering an increase of 40% every 5 years, comparable to other European countries, 6.000.000 CT examinations can be estimated for 2010.

The primary objective of the study is to obtain a snapshot of Italian CT practice in adults and children that is up-to-date in regards to information concerning multidetector 16- and 64- row CT. A second goal is to update the national reference dose levels.

The study should further establish a sustainable database for the ongoing collation of further data from local surveys of CT. This will facilitate the analysis of trends and periodic review of national reference doses for CT in a way similar to other European countries.

Radiology departments dealing with adult and paediatric CT in Italy will receive an invitation to participate to the survey and a questionnaire regarding some important features of their CT equipment. Four common protocols will be used for dose calculation: CT scan of the head, lumbar spine, chest and abdomen. Cardiac CT data will be collected only for adults, as in children other examinations, such as MR are commonly preferred to CT just for radioprotection reasons.