Photoacoustic Imaging for Prostate Brachytherapy
January 2014
in “
cIRcle (University of British Columbia)
”
TLDR Photoacoustic imaging can detect prostate brachytherapy seeds better with enhanced contrast methods, but depth limits remain.
Photoacoustic (PA) imaging was explored as a promising technique for detecting brachytherapy seeds in prostate brachytherapy due to the high absorption coefficient of metallic seeds, which provided high imaging contrast. However, the technique faced limitations in imaging depth due to optical attenuation in tissue. The study tested methods to enhance PA contrast, such as coating seeds with contrast-enhancing materials, which increased the signal-to-noise ratio (SNR) by 18 dB and doubled the imaging depth to 5 cm. Silver coating improved SNR by 5 dB, and using dyed ethanol solution as a contrast agent showed comparable improvements. Additionally, a novel method for tissue typing was proposed, utilizing temperature-induced changes in tissue parameters like the speed of sound. Experiments showed a 6.9±1.5 %/min increase in PA intensity in porcine liver and a 4.2±1.5 %/min decrease in bovine fat, suggesting potential for tissue differentiation through PA intensity analysis.
