Helpfulness of effective atomic number image in forensic dental identification: Photon-counting computed tomography is suitable

Takashi Asahara; Shunsuke Okada; Hiroaki Hayashi; Tatsuya Maeda; Rina Nishigami; Daiki Kobayashi; Chihiro Kurose; Natsumi Kimoto; Sota Goto; Miki Hisatomi; Yoshinobu Yanagi; Toshihiro Iguchi

doi:10.1016/j.compbiomed.2024.109333

Helpfulness of effective atomic number image in forensic dental identification: Photon-counting computed tomography is suitable

Comput Biol Med. 2024 Nov 9:184:109333. doi: 10.1016/j.compbiomed.2024.109333. Online ahead of print.

Authors

Affiliations

¹ Department of Radiological Technology, Faculty of Health Sciences, Okayama University, Okayama, 700-8558, Japan. Electronic address: takashi.asahara.111@gmail.com.
² Department of Oral and Maxillofacial Radiology, Okayama University Hospital, Okayama, 700-8525, Japan. Electronic address: okd@okayama-u.ac.jp.
³ College of Transdisciplinary Sciences for Innovation, Kanazawa University, Ishikawa, 920-1192, Japan. Electronic address: hayashi.hiroaki@staff.kanazawa-u.ac.jp.
⁴ Graduate School of Medical Sciences, Kanazawa University, Ishikawa, 920-0942, Japan. Electronic address: tatsuya.maeda.1108@gmail.com.
⁵ Graduate School of Medical Sciences, Kanazawa University, Ishikawa, 920-0942, Japan. Electronic address: nishigami.rina@gmail.com.
⁶ Graduate School of Medical Sciences, Kanazawa University, Ishikawa, 920-0942, Japan. Electronic address: kobayashi.daiki.2022@gmail.com.
⁷ Division of Radiology, Medical Support Department, Okayama University Hospital, Okayama, 700-0914, Japan. Electronic address: kurose1@okayama-u.ac.jp.
⁸ Department of Radiological Science, Faculty of Health Sciences, Junshin Gakuen University, Fukuoka, 815-8510, Japan. Electronic address: natsumi.kimoto.0717@gmail.com.
⁹ Faculty of Health Science, Kobe Tokiwa University, Hyogo, 653-0838, Japan. Electronic address: s-goto@kobe-tokiwa.ac.jp.
¹⁰ Department of Oral and Maxillofacial Radiology, Okayama University Hospital, Okayama, 700-8525, Japan. Electronic address: tomi@md.okayama-u.ac.jp.
¹¹ Department of Dental Informatics, Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama University, Okayama, 700-8525, Japan. Electronic address: ya7@okayama-u.ac.jp.
¹² Department of Radiological Technology, Faculty of Health Sciences, Okayama University, Okayama, 700-8558, Japan. Electronic address: iguchi@s.okayama-u.ac.jp.

PMID: 39522368
DOI: 10.1016/j.compbiomed.2024.109333

Abstract

The identities of unidentified persons are often confirmed by matching dental treatment information. Although treatment restorations consisting of artificial materials can be confirmed visually and/or by X-ray photography, they should be quantitatively analyzed. This study demonstrates that effective atomic number (Z_eff) images can be created using photon-counting computed tomography (PC-CT) and used to identify artificial materials employed in dentistry. We examined a multi-energy phantom with known atomic number materials, artificial dental materials, and a head phantom in which various actual dental inlay-materials can be embedded in the tooth. To analyze Z_eff images, we used (ⅰ) a photon-counting CT (PC-CT), (ⅱ) a dual-energy CT (DE-CT), and (ⅲ) a photon-counting-type scanogram imaging system (PC-scanogram). An algorithm for Z_eff analysis using PC-CT was newly proposed in this study, in which two virtual monochromatic X-ray images of 70 keV and 100 keV were utilized. The PC-CT results were compared to those of DE-CT and PC-scanogram. The Z_eff images using PC-CT, DE-CT, and PC-scanogram were created properly with errors of ±0.40, ±0.21, and ±0.24, respectively. We indicated that the Z_eff value of artificial dental materials can be uniquely determined irrespective of the imaging system. Moreover, the same result could be obtained even when the artificial dental materials were embedded in a head phantom. In conclusion, the Z_eff values provide an important quantitative indicator for identifying and/or discriminating artificial dental materials. This paper also proposed a new procedure for forensic dentistry by demonstrating the possibility of diagnosis based on the quantitative analysis of artificial dental materials.

Keywords: Dental material; Effective atomic number image; Forensic human identification; Photon counting CT.