Location

La Jolla, CA

Start Date

1-1-1983 12:00 AM

Description

Although the use of thermoacoustic emission in ultrasonic non-destructive testing and in medical imaging has been discussed by Van Gutfeld, 1 among others, its application is principally confined to the use of laser beams and surface or thin-layer emissions. In this paper we propose a more general thermoacoustic method of non-destructive material testing in which deeply penetrating radiation generates thermoacoustic signals thoughout the volume of a material. These ideas are the outgrowth of early work by one of the authors, T. Bowen, in the use of thermoacoustic emissions in cosmic ray detection2 and experimental checks have been carried out in particle accelerator beams.3 Their application in the field of medical imaging has recently been discussed in two articles; one theoretical4 and the other presenting experimental results obtained using pulsed rf current on tissue phantoms and a human subject.5 In these articles it was shown that many forms of pulsed heating radiation, e.g., non-ionizing, ionizing, acoustical, etc., will induce thermal stress with the resulting acoustic emission yielding image information. It was also shown that the received acoustic pressure waveforms are proportional to the gradient of a function which depends on local thermal properties (coefficient of thermal expansion and specific heat) as well as the local density and the energy absorbed per pulse.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

2B

Chapter

Section 17: Thermal Waves and New Phenomena

Pages

1029-1038

DOI

10.1007/978-1-4613-3706-5_67

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 AM

Thermoacoustic NDE Imaging Induced by Deeply Penetrating Radiation

La Jolla, CA

Although the use of thermoacoustic emission in ultrasonic non-destructive testing and in medical imaging has been discussed by Van Gutfeld, 1 among others, its application is principally confined to the use of laser beams and surface or thin-layer emissions. In this paper we propose a more general thermoacoustic method of non-destructive material testing in which deeply penetrating radiation generates thermoacoustic signals thoughout the volume of a material. These ideas are the outgrowth of early work by one of the authors, T. Bowen, in the use of thermoacoustic emissions in cosmic ray detection2 and experimental checks have been carried out in particle accelerator beams.3 Their application in the field of medical imaging has recently been discussed in two articles; one theoretical4 and the other presenting experimental results obtained using pulsed rf current on tissue phantoms and a human subject.5 In these articles it was shown that many forms of pulsed heating radiation, e.g., non-ionizing, ionizing, acoustical, etc., will induce thermal stress with the resulting acoustic emission yielding image information. It was also shown that the received acoustic pressure waveforms are proportional to the gradient of a function which depends on local thermal properties (coefficient of thermal expansion and specific heat) as well as the local density and the energy absorbed per pulse.