Adult doses from computed tomography (CT) scanning of the abdomen at a general hospital in Malta.

Abstract

Objectives: The objectives of the project were to measure the values of CTDivol and DLP during abdomen-pelvis CT examinations, of adult patients at a general hospital room in Malta, compare the mean values with corresponding values in the international literature, observe how these values vary with patient mass, AP, transverse and mean diameter and suggest room Diagnostic Reference Levels. Research design: CTDivol and DLP from CT abdomen-pelvis tomographic images of adult patients were collected from anonymized P ACS images. The level of correlation with patient weight, transverse, AP, and mean diameter was investigated using standard statistical methods. Results: The main results of the project were: a) For the majority of patients the same value of CTDivol was obtained irrespective of the weight of patient/diameter of the patient. This anomalous result can be explained either through the fact that the maximum mA was set too low at the hospital concerned or simply that the smart mA was not functioning consistently. b) The average values of CTDivol and DLP were 18.6mGy and 771mGycm respectively, for standard sized patients. These values were generally above those found in the literature. c) These average values for CTDivol and DLP for standard patients were set as room DRLs. However, in view of the anomalous result these values should be considered provisional pending further investigation. Conclusion: Further research is necessary to investigate the exact cause of the anomalous results and to establish a rule connecting maximum mA setting and patient dimension. Further education and training of CT regarding the physics of CT is necessary as radiographer's need to be able to detect and report when such anomalous dose reports are returned by the CT system.