Use of radio astronomy techniques in the analysis of acoustic phased array signals from the body Stephen Hughes, Madeleine McIntyre, Sanjay Mishra, Queensland University of Technology Steven Tingay, Curtin University of Technology, Perth, WA Graham Tronc, Wesley Hospital, Brisbane Suresh R. Devasahayam, Christian Medical Centre, Vellore, India NRAO / AUI / NSF

Research question Is it possible to use the correlation techniques used in radio astronomy to extract diagnostic information from sounds generated naturally in the body– e.g. leaking blood vessels, fetal heart rate, cancer cell death during chemotherapy, etc? Pinard stethoscope being used to listen to fetal heart beats in India

At the Paul Wild Observatory, Narribri, NSW, radio signals are collected using a phased array of six 22- m radio dishes Signals received at the focus of each dish are amplified using cryogenic electronics Digitised signals are sent to the control building via fibre optic cable….. and correlated by a hardware correlator.

Wavefront from space Radio dishes 1 2 ctct Wavefronts coming in at a slightly different angle to each other Radio dishes Radio image of a spiral galaxy

+ – +9V -9V 10 k  to ADC 10 k  150 k  Electret microphone 100 k  24.1 nF Four channels, simultaneous sampling, 100 kHz, 16-bit

Time domain signal of abdominal recording from a pregnant mother Autocorrelation function Some structure present which may be due to the maternal and fetal heart beat

Ch1 Ch2 FFT Filter × Complex conjugate IFFTCCF Software correlator pipeline Software based on the DiFX correlator developed by Tingay et al. (PERL -> Matlab -> Scilab)

Heart sound – no gel Heart sound –gelSpectrum of heart sound – gel Plastic holder for electret microphone with gel interface Filtered heart sound – gel

Research plan (cancer) Build an array acoustic sensors (e.g. microphones/accelerometers/piezoelectric elements) Develop software to calculate the CCF of multiple sensor baselines –can an acoustic image be generated? See if it is possible to detect cancer cells dying as a result of chemotherapy drugs Develop a system for the early detection of the efficacy or otherwise of chemotherapeutic agents Investigate ways of being able to transmit acoustic data over wireless networks to a central correlator facility Tumor Acoustic phased array

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