Calibration of HIFU intensity fields measured using an infra-red camera

A Shaw, V Khokhlova, S Bobkova, L Gavrilov, Jeffrey Hand

Research output: Chapter in Book/Report/Conference proceedingConference paper

10 Citations (Scopus)

Abstract

A trend in HIFU technologies is to use 2D phased arrays that offer electronic steering of a single focus and formation of patterns of multiple foci. Conventional methods to characterize array fields using scanned hydrophone would be prohibitively slow given the potentially large number of focusing conditions. An alternative technique for rapid qualitative assessment of intensity distributions was recently developed. The method is based on infrared camera measurements of the temperature rises induced by low amplitude short ultrasonic bursts in a thin absorber. Here, the method is extended to estimate the absolute values of intensity in a field of a 2D 1-MHz randomized phased array. Two approaches were implemented. In the first approach it was assumed that the measured temperature rise at the surface of the absorber is proportional to the free field intensity. The second approach correlated the temperature rise measured in an absorber and calculated from the modelled acoustic field and the heat transfer equation. Corresponding correction factors between the free field intensity and temperature was obtained and introduced in the conversion of temperature images to intensity. Free field distributions in water and focusing through ribs were recorded and simulated. Good correlation between the measured and modeled results in both spatial distributions and the absolute values of intensity was demonstrated.
Original languageEnglish
Title of host publicationJournal of Physics: Conference Series 279 (2011) 012019
PublisherIOP PUBLISHING LTD
Pages012019
Number of pages6
Volume279
ISBN (Electronic)10.1088/1742-6596/279/1/012019
Publication statusPublished - 2011
EventAdvanced Metrology for Ultrasound in Medicine (AMUM 2010) - National Physical Laboratory, Teddington, United Kingdom
Duration: 12 May 201014 May 2010

Publication series

NameJournal of Physics: Conference Series
PublisherIoP

Conference

ConferenceAdvanced Metrology for Ultrasound in Medicine (AMUM 2010)
Country/TerritoryUnited Kingdom
CityTeddington
Period12/05/201014/05/2010

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