SignificancePhotoacoustic (PA) technology shows great potential for bone assessment. However, the PA signals in cancellous bone are complex due to its complex composition and porous structure, making such signals challenging to apply directly in bone analysis.AimWe introduce a photoacoustic differential attenuation spectrum (PA-DAS) method to separate the contribution of the acoustic propagation path to the PA signal from that of the source, and theoretically and experimentally investigate the propagation attenuation characteristics of cancellous bone.ApproachWe modified Biot’s theory by accounting for the high frequency and viscosity. In parallel with the rabbit osteoporosis model, we build an experimental PA-DAS system featuring an eccentric excitation differential detection mechanism. Moreover, we extract a PA-DAS quantization parameter—slope—to quantify the attenuation of high- and low-frequency components.ResultsThe results show that the porosity of cancellous bone can be evaluated by fast longitude wave attenuation at different frequencies and the PA-DAS slope of the osteoporotic group is significantly lower compared with the normal group (**p<0.01).ConclusionsFindings demonstrate that PA-DAS effectively differentiates osteoporotic bone from healthy bone, facilitating quantitative assessment of bone mineral density, and osteoporosis diagnosis.
Transrectal ultrasound (TRUS) guided biopsy is the standard procedure for evaluating the presence of prostate cancer. TRUS, however, has limited sensitivity to prostate tumors, nor can it differentiate aggressive cancer from non-aggressive ones. The emerging photoacoustic (PA) imaging combined with TRUS offers a great promise to solve this overarching issue, especially when powered by tumor-targeting contrast agent. In this work, we studied the feasibility of PA imaging to cover the entire prostate by using light illumination via the urethral track. Experiment was conducted on whole human prostates ex vivo. The light source was an array of light emitting diodes (LED) which has many advantages compared to solid state laser. The LED array was placed in the urethra, delivering light with fluence within the ANSI safety limit. A PA and ultrasound (US) dual modality system acquired the images in the same way as in TRUS. The imaging target was a 1-mm tube filled with ICG solution, mimicking the situation of a prostate tumor labeled with ICG contrast agent. The imaging results demonstrated that PA imaging can detect the ICG-filled tube at any place in the prostate, with an imaging depth over 20 mm. This study validated that PA imaging, when performed in a transrectal manner and combined with transurethral light illumination, is capable of molecular level imaging of the entire prostate noninvasively. The high sensitivity offered by PA imaging in detecting aggressive prostate cancer may contribute to prostate cancer management, e.g., enabling more accurate guidance for needle biopsy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.