Ambrogio, S; Baesso, R M; Bosio, F; Fedele, F; Ramnarine, K V; Zeqiri, B; Miloro, P (2022) A standard test phantom for the performance assessment of Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) thermal therapy devices. International Journal of Hyperthermia, 39 (1). pp. 57-68.

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Abstract

Test objects play a key role in medical physics. In the field of High Intensity Focused Ultrasound (HIFU) they are used for the standardisation and definition of treatment, Quality Assurance (QA), comparison of results across centres and calibration of devices. A HIFU test object which allows temperature measurement as a function of time, in a reference material compatible with Magnetic Resonance (MR) and ultrasound, has been developed. T-Type fine wire thermocouples were used as sensors and several correction methods for viscous heating artefacts were applied. The phantom was tested in a MR-HIFU Philips Sonalleve device over a period of 12 months demonstrating stability and validity to evaluate the performance of the device. It provided useful information regarding the MR-HIFU sessions and highlighted potential limitation of the existing QA and monitoring methods. The importance of temperature monitoring along the whole acoustic path is demonstrated MR Thermometry readings differ in the three MR plane views (coronal, sagittal, transverse), in particular when the focus is near a soft-tissue/bone interface, where there can be an MR signal loss with significant temperature (138% variation between the three plane views) and thermal dose underestimation. The test object proved to be easy to use and represent a valid tool for training, QA and research and development for MR guided HIFU and potentially Ultrasound guided devices.

Item Type:	Article
Keywords:	HIFU thermal ablation quality control phantom thermal dosimetry
Subjects:	Acoustics > Ultrasound Engineering Measurements > Thermal
Divisions:	Medical, Marine & Nuclear
Identification number/DOI:	10.1080/02656736.2021.2017023
Last Modified:	01 Feb 2022 14:10
URI:	https://eprintspublications.npl.co.uk/id/eprint/9330