Elena Lucano1,2, Micaela Liberti2, Tom Lloyd3, Francesca Apollonio2, Steve Wedan3, Wolfgang Kainz1, Leonardo M Angelone1. 1. US Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, Maryland, USA. 2. Universita degli Studi di Roma La Sapienza, Department of Information Engineering, Electronics, Telecommunications, Roma, Italy. 3. Imricor Medical Systems, Burnsville, Minnesota, USA.
Abstract
PURPOSE: This study aims to investigate how the positions of the feeding sources of the transmit radiofrequency (RF) coil, field orientation direction with respect to the patient, and patient dimensions affect the global and local electromagnetic exposure in human body models. METHODS: Three RF coil models were implemented, namely a specific two-source (S2) feed and two multisource feed configurations: generic 32-source (G32) and hybrid 16-source (H16). Thirty-two feeding conditions were studied for the S2, whereas two were studied for the G32 and H16. The study was performed using five human body models. Additionally, for two of the body models, the case of a partially implanted lead was evaluated. RESULTS: The results showed an overall variation due to coil feeding conditions of the whole-body specific absorption rate (SAR) of less than 20%, but deviations up to 98% of the magnitude of the electric field tangential to a possible lead path. For the analysis with the partially implanted lead, a variation of local SAR at the tip of the lead of up to 60% was observed with respect to feed position and field orientation direction. CONCLUSION: The results of this study suggest that specific information about feed position and field orientation direction must be considered for an accurate evaluation of patient exposure. Magn Reson Med 79:1135-1144, 2018.
PURPOSE: This study aims to investigate how the positions of the feeding sources of the transmit radiofrequency (RF) coil, field orientation direction with respect to the patient, and patient dimensions affect the global and local electromagnetic exposure in human body models. METHODS: Three RF coil models were implemented, namely a specific two-source (S2) feed and two multisource feed configurations: generic 32-source (G32) and hybrid 16-source (H16). Thirty-two feeding conditions were studied for the S2, whereas two were studied for the G32 and H16. The study was performed using five human body models. Additionally, for two of the body models, the case of a partially implanted lead was evaluated. RESULTS: The results showed an overall variation due to coil feeding conditions of the whole-body specific absorption rate (SAR) of less than 20%, but deviations up to 98% of the magnitude of the electric field tangential to a possible lead path. For the analysis with the partially implanted lead, a variation of local SAR at the tip of the lead of up to 60% was observed with respect to feed position and field orientation direction. CONCLUSION: The results of this study suggest that specific information about feed position and field orientation direction must be considered for an accurate evaluation of patient exposure. Magn Reson Med 79:1135-1144, 2018.
Authors: Elena Lucano; Micaela Liberti; Gonzalo G Mendoza; Tom Lloyd; Maria Ida Iacono; Francesca Apollonio; Steve Wedan; Wolfgang Kainz; Leonardo M Angelone Journal: IEEE Trans Biomed Eng Date: 2015-12-17 Impact factor: 4.538
Authors: Andreas Christ; Wolfgang Kainz; Eckhart G Hahn; Katharina Honegger; Marcel Zefferer; Esra Neufeld; Wolfgang Rascher; Rolf Janka; Werner Bautz; Ji Chen; Berthold Kiefer; Peter Schmitt; Hans-Peter Hollenbach; Jianxiang Shen; Michael Oberle; Dominik Szczerba; Anthony Kam; Joshua W Guag; Niels Kuster Journal: Phys Med Biol Date: 2009-12-17 Impact factor: 3.609
Authors: Eugenio Mattei; Michele Triventi; Giovanni Calcagnini; Federica Censi; Wolfgang Kainz; Gonzalo Mendoza; Howard I Bassen; Pietro Bartolini Journal: Biomed Eng Online Date: 2008-03-03 Impact factor: 2.819