Basic ablation phenomena during laser thrombolysis

Ujwal S. Sathyam; Alan Shearin; Scott A. Prahl

doi:10.1117/12.275038

22 May 1997 Basic ablation phenomena during laser thrombolysis

Ujwal S. Sathyam, Alan Shearin, Scott A. Prahl

Proceedings Volume 2970, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VII; (1997) https://doi.org/10.1117/12.275038
Event: BiOS '97, Part of Photonics West, 1997, San Jose, CA, United States

Abstract

This paper presents studies of microsecond ablation phenomena that take place during laser thrombolysis. The main goals were to optimize laser parameters for efficient ablation, and to investigate the ablation mechanism. Gelatin containing an absorbing dye was used as the clot model. A parametric study was performed to identify the optimal wavelength, spot size, pulse energies, and repetition rate for maximum material removal. The minimum radiant exposures to achieve ablation at any wavelength were measured. The results suggest that most visible wavelengths were equally efficient at removing material at radiant exposures above threshold. Ablation was initiated at surface temperatures just above 100 degrees Celsius. A vapor bubble was formed during ablation. Less than 5% of the total pulse energy is coupled into the bubble energy. A large part of the delivered energy is unaccounted for and is likely released partly as acoustic transients from the vapor expansion and partly wasted as heat. The current laser and delivery systems may not be able to completely remove large clot burden that is sometimes encountered in heart attacks. However, laser thrombolysis may emerge as a favored treatment for strokes where the occlusion is generally smaller and rapid recanalization is of paramount importance. A final hypothesis is that laser thrombolysis should be done at radiant exposures close to threshold to minimize any damaging effects of the bubble dynamics on the vessel wall.

Citation Download Citation

Ujwal S. Sathyam, Alan Shearin, and Scott A. Prahl "Basic ablation phenomena during laser thrombolysis", Proc. SPIE 2970, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VII, (22 May 1997); https://doi.org/10.1117/12.275038

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

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.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available