Background/introduction
Computed tomography (CT) of the paranasal sinus and facial skull represents the gold standard for diagnosis of the extent and severity of inflammatory sinus disease. Radiation exposure in this examination is a major concern, as radiosensitive organs as the optic lenses are included in the scan volume, and are exposed to direct or scattered radiatio. For this reason various dose-reduction strategies have been discussed before. Amongst other things a recently introduced tin (Sn) filter absorbs less relevant low-energy photons and shifts the x-ray spectrum towards...
Description of activity and work performed
Paranasal sinus low-dose CT was performed in 120 patients with three protocols (assigend to group 1 - 3):
Group 1: 192-row DSCT 100 kV, tin-filter, IR [SOMATOM Force, Siemens Healthcare GmbH]
Group 2: 64-row CT 120 kV, IR [SOMATOM Definition AS, Siemens Healthcare GmbH]
Group 3: 16-row CT 120 kV, FBP [SOMATOM Sensation, Siemens Healthcare GmbH]
The CT attenuation (in Hounsfield units [HU]) was assessed and signal-to-noise-ratios (SNR) were compared. Subjective image quality was assessed using a five-point Likert-scale: 1 = excellent; 2 = good;...
Conclusion and recommendations
Evidently, the understanding of “low” has changed during the past 2 decades. We took up the term “ultra-low-dose", which was initally introduced by Schulz et al in 2012, for our study.
The use of a tin-filter in combination with low-kV setting and IR allows for true ultra-low-dose imaging of the paranasal sinus with a mean effective dose of 0.012 mSv per scan when inflammtory sinus disease is suspected.
Since we are committed to the ALARA principle we find that an exhaustion of the current technical...
Personal/organisational information
B. M. W. Petritsch; Würzburg/DE - nothing to disclose A. Weng; Würzburg/DE - nothing to disclose T. A. Bley; Würzburg/DE - nothing to disclose A. Kosmala; Würzburg/DE - nothing to disclose
References
Bulla S, Blanke P, Hassepass F et al. Reducing the radiation dose for low-dose CT of the paranasal sinuses using iterative reconstruction: feasibility and image quality. Eur J Radiol. 2012;81: 2246–2250.
Brem MH, Zamani AA, Riva R et al. Multidetector CT of the paranasal sinus: potential for radiation dose reduction. Radiology. 2007;243: 847–852.
Czechowski J, Janeczek J, Kelly G et al. Radiation dose to the lens in sequential and spiral CT of the facial bones and sinuses. Eur Radiol. 2001;11: 711–713.
Deak PD, Smal Y,...
