Patient doses from standard and spiral CT of the head using a fast twin-beam system.

Abstract

Investigations were carried out on a novel type of CT scanner, the Elscint CT-Twin, for comparison and optimization of the patient dose caused by standard and spiral CT of the head. For selected CT parameters, organ doses of the Alderson head phantom were measured with thermoluminescent dosemeters. Organ doses were also calculated using the normalized computed tomography dose index (CTDIn) combined with organ dose conversion factors. Then effective doses were deduced. For standard and spiral head CT examinations brain, red bone marrow and bone surface receive the main contributions to effective dose. This amounts to 0.9 and 0.8 mSv for routine standard and spiral CT, respectively, if the combination "dual-slice" mode, 250 mAs per rotation, 5 mm nominal slice width and a packing factor of 1.0, is applied. In clinical practice, for spiral CT head examinations the effective dose has been reduced to 0.7 mSv while guaranteeing adequate image quality, as assessed by determination of low and high contrast resolution. The effective dose values obtained are in the lower part of the range of values published in the literature. The dose determinations showed that, from the aspect of radiation protection of the patient, CT examinations with nominal slice widths between 0.5 and 1 mm as well as packing factors greater than 1.0 should be restricted to really necessary cases.

Radiation exposure in multi-slice versus single-slice spiral CT: results of a nationwide survey

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The possibility of application of spiral brain computed tomography to traumatic brain injury

“…On the other hand, the spiral CT had the advantage of shorter test time required and its multidimensional reconstruction providing 3-dimensional image, although there were some limitations such as decreased image clarity. Therefore, it is now used for anatomical evaluation of practically all body parts with the development of the technology [10,11]. Technical advancements of spiral imaging technique have remarkably reduced the time of CT evaluation and could make CT into a criterion standard of evaluation even in the hemodynamically unstable patients regarded as the contraindication in the past.…”

Optimization of hepatic lesion detection with computed tomography (CT): Is randomization of lesion location necessary?

“…This is a global phenomenon, with surveys from the United Kingdom, Germany, Switzerland, East Anglia, Canada, United States of America, New Zealand and Australia reporting significant increases in CT usage and population dose over time [4][5][6][7][8][9][10][11][12][13][14][15] . Although the magnitude of the affect of increased collective doses from CT on the cancer risk to the population is not certain [16][17][18] , the consensus from governments, radiation regulatory bodies, and radiology associations and professionals is that CT dose optimization, meaning reduction of CT doses to the lowest necessary for diagnostic accuracy, is necessary 3, 19-23 .…”