M Hasegawa1, K Miyata, Y Abe, T Ishigami. 1. Department of Partial Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan. hasegawa-mk@dent.nihon-u.ac.jp
Abstract
OBJECTIVES: To estimate the risk of injury from radiofrequency (RF) heating of metallic dental devices in use during 3.0 T MRI. METHODS: The whole-body specific absorption rate (WB-SAR) was calculated on the basis of saline temperature elevation under the maximum RF irradiation for 15 min to determine the operation parameters for the heating test. The temperature changes of three types of three-unit bridges, a full-arch fixed dental prosthesis and an orthodontic appliance in use during MRI with a 3.0 T MR system (Magnetom(®) Verio; Siemens AG, Erlangen, Germany) were then tested in accordance with the American Society for Testing and Materials F2182-09 standardized procedure under the maximum RF heating during 15 min RF irradiation. RESULTS: The system console-predicted WB-SAR was approximately 1.4 W kg(-1) and that measured with a saline phantom was 2.1 W kg(-1). In the assessment of RF heating, the highest temperature increase was +1.80 °C in the bridges, +1.59 °C in the full-arch fixed dental prosthesis and +2.61 °C in the orthodontic appliance. CONCLUSIONS: The relatively minor RF heating of dental casting material-based prostheses in Magnetom Verio systems in the normal operating mode should not pose a risk to patients. However, orthodontic appliances may exhibit RF heating above the industrial standard (CENELEC standard prEN45502-2-3); therefore, the wire should be removed from the bracket or a spacer should be used between the appliance and the oral mucosa during MRI.
OBJECTIVES: To estimate the risk of injury from radiofrequency (RF) heating of metallic dental devices in use during 3.0 T MRI. METHODS: The whole-body specific absorption rate (WB-SAR) was calculated on the basis of saline temperature elevation under the maximum RF irradiation for 15 min to determine the operation parameters for the heating test. The temperature changes of three types of three-unit bridges, a full-arch fixed dental prosthesis and an orthodontic appliance in use during MRI with a 3.0 T MR system (Magnetom(®) Verio; Siemens AG, Erlangen, Germany) were then tested in accordance with the American Society for Testing and Materials F2182-09 standardized procedure under the maximum RF heating during 15 min RF irradiation. RESULTS: The system console-predicted WB-SAR was approximately 1.4 W kg(-1) and that measured with a saline phantom was 2.1 W kg(-1). In the assessment of RF heating, the highest temperature increase was +1.80 °C in the bridges, +1.59 °C in the full-arch fixed dental prosthesis and +2.61 °C in the orthodontic appliance. CONCLUSIONS: The relatively minor RF heating of dental casting material-based prostheses in Magnetom Verio systems in the normal operating mode should not pose a risk to patients. However, orthodontic appliances may exhibit RF heating above the industrial standard (CENELEC standard prEN45502-2-3); therefore, the wire should be removed from the bracket or a spacer should be used between the appliance and the oral mucosa during MRI.
Authors: Kenneth B Baker; Jean A Tkach; John A Nyenhuis; Michael Phillips; Frank G Shellock; Jorge Gonzalez-Martinez; Ali R Rezai Journal: J Magn Reson Imaging Date: 2004-08 Impact factor: 4.813
Authors: M Hasegawa; K Miyata; Y Abe; T Ishii; T Ishigami; K Ohtani; E Nagai; T Ohyama; Y Umekawa; S Nakabayashi Journal: Dentomaxillofac Radiol Date: 2015-03-18 Impact factor: 2.419
Authors: Katrine Mølgaard Johannsen; João Marcus de Carvalho E Silva Fuglsig; Brian Hansen; Ann Wenzel; Rubens Spin-Neto Journal: Oral Radiol Date: 2022-09-30 Impact factor: 1.882