Contents lists available at ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem Organ dose and radiogenic risk in dental cone-beam computed tomography examinations Aljawhara H. Almuqrin a,* , Nissren Tamam a , A. Abdelrazig b , A. Elnour c , Abdelmoneim Sulieman d a Physics Department, College of Sciences, Princess Nourah Bint Abdulrahman University, P.O Box 84428, Riyadh, 11671, Saudi Arabia b Diagnostic Radiology Department, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia c Radiologic Science Department, The National Ribat University, Khartoum, Sudan d Prince Sattam Bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P.O. Box 422, Alkharj 11942, Saudi Arabia ARTICLE INFO Keywords: Cone beam CT Radiation dose Organ dose Radiation risk Dental imaging ABSTRACT During the last decade, the development of cone beam computed tomography (CBCT) has led to a large range of imaging methods. CBCT has advantages compared to other extraoral radiographic imaging, but its contribution to radiation dose in patients is a point of concern. This study aims to provide a full understanding and de- termination of absorbed dose and an estimation of effective dose to the thyroid, bone marrow, salivary glands and brain in patients during CBCT examinations and to estimate the radiogenic risk resulting from radiation exposure. In this study, a total of 157 pediatric and adult patients with different indications were investigated at the dental clinic. All procedures were performed using Planmeca ProMax 3D Max. Sensitive organ equivalent doses were estimated using PCXMC software. Organ equivalent doses were also estimated using PCXMC soft- ware. The fixed tube voltage was set to 90.0 kVp, the mean tube current was 12.7.0 mA (range: 8.0 to 14.0) and the mean exposure time was 12.5 ± 1.8 s (range: 12.0–16.0). The overall mean patient effective dose was 150.8 μSv (range: 22.4–210.0). Salivary gland equivalent dose was the highest of all the organs measured as no protective shield was used in these patients. Patient doses were slightly higher compared to those in previous studies. Poor patient protection conditions were noted. Staff training is a vital priority regardless of a low dose of CBCT compared to other imaging modalities. 1. Introduction Ionizing radiation dose to the public due to cone-beam computed tomography (CBCT) has been increasing since its introduction into the clinical environment in 1996 (CRCPD, 2017; Alaei and Spezi, 2015). CBCT has significantly contributed to health care improvements in dentistry and image-guided radiation therapy in terms of patient posi- tioning, orthopedics, angiography, and other medical specialties. Con- ventional CT can provide excellent image quality of maxillofacial and facial structures but with higher doses which may reach 31.6 mGy per CT procedure (Hoxworth et al., 2014). Patient radiation effective doses resulting from CBCT examinations are greater compared to conven- tional dental imaging procedures where patient doses range from 18.5 to 1073 μSv per procedure based on the field of view (FOV) and ima- ging protocol (Ludlow et al., 2015; Vassileva & Stoyanov, 2010; Roberts et al., 2009). In radiobiology, it is widely accepted that exposure to ionizing radiation carries a cancer risk proportional to the dose ac- cording to the linear no-threshold model (Weber and Zanzonico, 2017). The thyroid gland, which is a radiosensitive organ, is exposed to high doses during CBCT procedures, even though it is not the organ of in- terest, if a protective shield is not used (Theodorakou et al., 2012). Previous studies reported a wide range of thyroid equivalent doses from 0.166 to 1.33 mGy ((Ludlow and Walker, 2013; Al Najjar et al., 2013; Theodorakou et al., 2012). In 2015, Al-Okshi et al., reported that there was a significant variation of up to 20-fold of a difference regarding effective dose for the same CBCT machine with the same field size (Al- Okshi and Lindh, 2015). In addition, as reported by the International Commission on Radiological Protection (ICRP), eye lens radiobiological effect has a lower threshold (500 mGy) for eye lens opacity initiation and cataract induction than previously thought (2000 mGy), or even the stochastic risk paradigm (ICRP, 2012). However, the radiation dose from justified CBCT procedures for accurate diagnosis outweighs the projected risk of cancer resulting from radiation exposure. The risk increases with the amount of exposure (e.g. repeated exposures) and in young patients. To our knowledge, this is the first study to evaluate patient doses in CBCT examinations and other dental imaging https://doi.org/10.1016/j.radphyschem.2020.108971 Received 1 August 2019; Received in revised form 4 May 2020; Accepted 6 May 2020 * Corresponding author. Princess Nourah Bint Abdulrahman University , Saudi Arabia. E-mail address: ahalmoqren@pnu.edu.sa (A.H. Almuqrin). Radiation Physics and Chemistry 176 (2020) 108971 Available online 29 July 2020 0969-806X/ © 2020 Elsevier Ltd. All rights reserved. T