European Journal of Radiology 81 (2012) 1140–1145 Contents lists available at ScienceDirect European Journal of Radiology journa l h o me pa ge: www.elsevier.com/locate/ejrad Radiation dose of digital tomosynthesis for sinonasal examination: Comparison with multi-detector CT Haruhiko Machida a,∗ , Toshiyuki Yuhara a , Mieko Tamura a , Tomokazu Numano b , Shinji Abe b , John M. Sabol c , Shigeru Suzuki d , Eiko Ueno a a Department of Radiology, Tokyo Women’s Medical University Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan b Department of Radiological Sciences, Tokyo Metropolitan University of Health Sciences, Tokyo 116-8551, Japan c GE Healthcare, 3000 North Grandview Blvd., Waukesha, WI 53188, USA d Department of Radiology, Saitama Red Cross Hospital, 8-3-33 kamiochiai, Chuo-ku, Saitama 338-0001, Japan a r t i c l e i n f o Article history: Received 8 November 2010 Received in revised form 13 March 2011 Accepted 16 March 2011 Keywords: Computed tomography Digital tomosynthesis Paranasal sinuses Radiation dosage Radiography X-ray tomography a b s t r a c t Objective: Using an anthropomorphic phantom, we have investigated the feasibility of digital tomosyn- thesis (DT) of flat-panel detector (FPD) radiography to reduce radiation dose for sinonasal examination compared to multi-detector computed tomography (MDCT). Materials and methods: A female Rando phantom was scanned covering frontal to maxillary sinus using the clinically routine protocol by both 64-detector CT (120 kV, 200 mA s, and 1.375-pitch) and DT radiography (80 kV, 1.0 mA s per projection, 60 projections, 40 ◦ sweep, and posterior–anterior projections). Glass dosimeters were used to measure the radiation dose to internal organs including the thyroid gland, brain, submandibular gland, and the surface dose at various sites including the eyes during those scans. We compared the radiation dose to those anatomies between both modalities. Results: In DT radiography, the doses of the thyroid gland, brain, submandibular gland, skin, and eyes were 230 ± 90 Gy, 1770 ± 560 Gy, 1400 ± 80 Gy, 1160 ± 2100 Gy, and 112 ± 6 Gy, respectively. These doses were reduced to approximately 1/5, 1/8, 1/12, 1/17, and 1/290 of the respective MDCT dose. Conclusion: For sinonasal examinations, DT radiography enables dramatic reduction in radiation exposure and dose to the head and neck region, particularly to the lens of the eye. © 2011 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Recently, radiography systems based on full-field, flat-panel cesium iodide, amorphous silicon detectors have become commer- cially available. These systems provide improved image quality relative to that of screen-film and storage phosphor systems, and possibilities for reduced radiation exposure and advanced appli- cations. Digital tomosynthesis (DT) radiography is an advanced application that removes overlying structures, enhances local tis- sue separation, and provides depth information about structures of interest by providing “digitally synthesized, or reconstructed, tomographic images”. DT radiography has been reported to be useful in a wide variety of clinical fields [1–5]; it can also be applied for the evaluation of sinonasal diseases playing a middle role between con- ventional radiography and multi-detector computed tomography ∗ Corresponding author. Tel.: +81 3 3810 1111; fax: +81 3 3894 0282. E-mail address: machira@dnh.twmu.ac.jp (H. Machida). (MDCT). In our experience, when the typical clinical symptoms and physical findings are present in a patient, this time- and cost-saving examination enables easy and effective visualization of fluid collection and/or mucosal thickening for the diagnosis of acute sinusitis, taking advantage of the high contrast of the sur- rounding air in the sinuses in combination with upright patient positioning (Fig. 1). Thin-slice, helical scans with MDCT provides excellent multi- planar reformation (MPR) images that are important to the successful utilization of minimally invasive endoscopic sinus surgery in treating various sinonasal diseases. However, the radia- tion exposure delivered by the thin-slice, helical, MDCT sinonasal examination, especially to the lens of the eye, a particularly radiosensitive organ, is an important issue that needs to be addressed. To our knowledge, radiation dose to various anatomies in the head and neck region, including the eye lens, has thus far not been assessed and reported for DT sinonasal radiography. The purpose of the present study was to use an anthropomorphic phan- tom to compare the radiation dose of routine clinical sinonasal examination protocols between MDCT and DT radiography. 0720-048X/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrad.2011.03.064