Entries by Katy

Photoacoustic image guidance and robotic visual servoing to mitigate fluoroscopy during cardiac catheter interventions

Many cardiac interventional procedures (e.g., radiofrequency ablation) require fluoroscopy to navigate catheters in veins toward the heart. However, this image guidance method lacks depth information and increases the risks of radiation exposure for both patients and operators. To overcome these challenges, we developed a robotic visual servoing system that maintains visualization of segmented photoacoustic signals […]

Photoacoustic imaging capabilities of light emitting diodes (LED) and laser sources: a comparison study

Photoacoustic imaging (PAI) maps functional and molecular optical contrasts of tissue at ultrasonic spatial resolution and imaging depth. To generate detectable PA signals from deeper regions, expensive, bulky and high-energy class IV lasers are conventionally employed. Light emitting diodes (LED) have recently emerged as an alternative excitation source for PA imaging offering many advantages including […]

Simulations and human cadaver head studies to identify optimal acoustic receiver locations for minimally invasive photoacoustic-guided neurosurgery

Real-time intraoperative guidance during minimally invasive neurosurgical procedures (e.g., endonasal transsphenoidal surgery) is often limited to endoscopy and CT-guided image navigation, which can be suboptimal at locating underlying blood vessels and nerves. Accidental damage to these critical structures can have severe surgical complications, including patient blindness and death. Photoacoustic image guidance was previously proposed as […]

Three-dimensional clinical handheld photoacoustic/ultrasound scanner

Clinical 2D photoacoustic (PA) imaging can be easily implemented in a traditional ultrasound (US) system. However, 3D PA imaging is still preferable because 2D B-mode PA/US imaging suffers from low reproducibility and high-operator dependency. Here, we demonstrate a compact clinical handheld 3D PA/US scanner using an 1D linear array US transducer combined with a mechanical […]

Multiwavelength photoacoustic temperature measurement with phantom and ex-vivo tissue

Photoacoustic temperature measurement is a new type of thermometric technology with noninvasive, real-time, high precision and space resolution. For improving the measurement accuracy and reliability, the method of using a multiwavelength photoacoustic signal to monitor the temperature named as multiwavelength photoacoustic temperature measurement was proposed in this paper. Based on the basic photoacoustic effect theory, […]

Portable probe design for photoacoustic imaging in vivo

A low-cost adjustable illumination scheme for hand-held photoacoustic imaging probe is presented, manufactured and tested in this paper. Compared with traditional photoacoustic probe design, it has the following advantages: (1) Different excitation modes can be selected as needed. By tuning control parameters, it can achieve bright-field, dark-field, and hybrid field light illumination schemes. (2) The […]

Empirical assessment of laser safety for photoacoustic-guided liver surgeries

Photoacoustic imaging is a promising technique to provide guidance during multiple surgeries and procedures. One challenge with this technique is that major blood vessels in the liver are difficult to differentiate from surrounding tissue within current safety limits, which only exist for human skin and eyes. In this paper, we investigate the safety of raising […]

Vascular recognition system based on photoacoustic detection

Currently, biometrics are widely used in recognition technology; however, biometric recognition systems are vulnerable to malicious spoofing attacks. Thus, the security of such systems requires enhancements. This paper reports a novel vascular recognition system based on simple photoacoustic imaging to resist spoofing attacks. The amplitude and the delay of the maximum-value arrival time of the […]

Polyacrylamide hydrogel phantoms for performance evaluation of multispectral photoacoustic imaging systems

As photoacoustic imaging (PAI) begins to mature and undergo clinical translation, there is a need for well-validated, standardized performance test methods to support device development, quality control, and regulatory evaluation. Despite recent progress, current PAI phantoms may not adequately replicate tissue light and sound transport over the full range of optical wavelengths and acoustic frequencies employed by […]

Characterizing the aggressiveness of prostate cancer using an all-optical needle photoacoustic sensing probe: feasibility study

In our previous studies, we have developed a prototype interstitial needle sensing probe that can acquire broadband A-line photoacoustic (PA) signals encoding both tissue microarchitecture and histochemical information comparable to that accessible by histology. Paving the road toward clinical translation of this technology, we replaced the piezoelectric hydrophone in the needle PA probe with a […]