Abstract
Photoacoustic tomography (PAT), a promising medical imaging method that combines optical and ultrasound techniques, has been developing for decades mostly in preclinical application. A recent trend is to utilize the economical laser source to develop a low-cost sensing and imaging system, which aims at an affordable solution in clinical application. These low-cost laser sources have different modulation modes such as pulsed modulation, continuous modulation and coded modulation to generate different profiles of PA signals in photoacoustic (PA) imaging. In this paper, we review the recent development of the photoacoustic sensing and imaging based on the economical laser sources such as laser diode (LD) and light-emitting diode (LED) in different kinds of modulation types, and discuss several representative methods to improve the performance of such imaging systems based on low-cost laser sources. Finally, some perspectives regarding the future development of portable PAT systems are discussed, followed by the conclusion.
Highlights
Photoacoustic tomography (PAT) is a kind of hybrid imaging modality, which employs the high imaging contrast of optical imaging and deep penetration of ultrasound imaging [1,2,3,4,5]
The light source usually comprises of a Q-switched Nd:YAG laser with nanosecond pulse duration and hundreds of mJ pulse energy, which is commonly used in different kinds of PAT imaging implementations, such as optical-resolution photoacoustic microscopy (OR-PAM), acoustic-resolution photoacoustic microscopy (AR-PAM) and photoacoustic computed tomography (PACT) [14,15,16,17,18,19]
Of PA imaging will photoacoustic sensing and imaging system categorized by different modulation ways. system
Summary
PAT is a kind of hybrid imaging modality, which employs the high imaging contrast of optical imaging and deep penetration of ultrasound imaging [1,2,3,4,5]. The repetition rate of most high-power laser sources is relatively low (~tens of Hz), which may limit the imaging speed when data averaging is required. 2018, 18, 2264 sources is relatively low (~tens of Hz), which may limit the imaging speed when data averaging is required Another type of laser source, diode pumped laser such as that mentioned in Reference [23], can operate in the repetition rate of 50 Hz with the 80 mJ per pulse. Driver, there such are several modulation ways in signal excitation, such as pulsed modulation and Because semiconductor laser diodes can operate in high frequency with high-speed current continuous modulation. Of low-cost meantime, some signal enhancement methods to improve the SNR of PA imaging will photoacoustic sensing and imaging system categorized by different modulation ways. Some signal enhancement methods to improve the SNR of PA imaging system will be discussed
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