Effective radiation dose from semicoronal CT of the sacroiliac joints in comparison with axial CT and conventional radiography

Abstract

The aim of this study was to evaluate the radiation dose given by semicoronal CT of the sacroiliac joints (SIJs) in comparison with axial CT and conventional radiography. The total effective radiation doses given by serial contiguous semicoronal and axial CT, using 5-mm slices, 120 kV and 330 mAs, were determined by measurement of organ doses using an anthropomorphic Rando Alderson phantom paced with thermoluminescence dosimeters. The doses given by conventional anteroposterior (AP) and oblique projections of the SIJs were determined similarly. In a female the total effective dose by semicoronal CT was found to be more than six times lower than by axial CT and 2.5 times lower than the dose use to obtain a conventional AP radiograph, the values being 102, 678, and 255 µSv, respectively. The effective dose by semicoronal CT was only a little higher than the dose given to obtain two oblique radiographs. In a male with lead protection of the gonads the dose by semicoronal CT was four times lower than by axial CT, but higher than by conventional radiography. In conclusion, the effective dose by semicoronal CT of the SIJs is lower than by axial CT, and in females a semicoronal CT implies a lower effective radiation dose that used to obtain an AP radiograph.

The validity of the new york radiological grading criteria in diagnosing sacroiliitis by computed tomography

“…In the current study on a retrospective material, no measurements concerning radiation dose were made. In a study by JURIK et al (35) measuring effective dose, the dose to female gonads was reported to be 2.5 times lower for a semi-coronal CT examination (102 mSv) than for a single anteroposterior (AP) radiograph (255 mSv), and more than six times lower than for axial CT (678 mSv). However, the effective semi-coronal CT dose for men (100 mSv) was more than twice that of an AP radiography (39 mSv) when using effective lead shielding of the male gonads at radiography and CT.…”

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT

“…CT of the SIJs is associated with radiation exposure. Although optimal machine settings, the use of only a few slices (15,19), or a semicoronal scan plane (27) can reduce the radiation dose, it is more desirable to avoid radiation completely. This can be achieved by replacing CT with MR, though still keeping in mind the situations in which CT is superior to MR, i.e., detection of chronic bone changes in the ligamentous portion of the joint (29).…”

Diagnosis and Progression of Sacroiliitis in Repeated Sacroiliac Joint Computed Tomography

“…In addition, radiography, CT, and bone scintigraphy all give a radiation dose to the patient. In a study from 2002, it was reported that the effective dose from a semicoronal CT of the sacroiliac joints is 100  μ Sv for men and 102  μ Sv for women, compared to anterior-posterior (AP) projection radiography of the sacroiliac joints resulting in 39  μ Sv for men and 255  μ Sv for women [30]. Dose levels for sacroiliac joint CT from modern multidetector CT scanners with modern dose reducing image reconstruction algorithms are not available.…”