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The effect of frequency doubled double pulse Nd:YAG laser fiber proximity to the target stone on transient cavitation and acoustic emission.
J Urol. 2007 Apr; 177(4):1542-5.JU

Abstract

PURPOSE

Scant information has been published describing the effect of laser fiber distance from the stone target on the mechanism of calculus fragmentation. Using high speed photography and acoustic emission measurements we characterized the impact of laser fiber proximity on stone comminution. We evaluated the effect of laser fiber distance from the stone target on resultant cavitation bubble formation and shock wave generation.

MATERIALS AND METHODS

Stone fragmentation was assessed using a FREDDY (frequency doubled double pulse Nd:YAG) (World of Medicine, Orlando, Florida) laser and a holmium laser. The FREDDY laser was operated using a 420 microm fiber at an output energy of 120 and 160 mJ in single and double pulse settings, and a pulse repetition rate of 1 Hz. The holmium laser was operated using a 200 microm fiber at an output energy of 1 to 3 J and a pulse repetition rate of 1 Hz. The surface of a 1 cm square BegoStone (Bego, Bremen, Germany) attached to an X-Y-Z translational stage was aligned perpendicular to the laser fiber, which was immersed in a Lucite tank filled with water at room temperature. An Imacon 200 high speed camera was used to capture transient cavitation bubbles at a framing rate of up to 1,000,000 frames per second. Acoustic emission signals associated with shock waves generated during the rapid expansion and collapse of the cavitation bubble were measured using a 1 MHz focused ultrasound transducer.

RESULTS

At laser fiber distances of 3.0 mm or less cavitation bubbles and shock waves were observed with the FREDDY laser. In contrast to the holmium laser, the bubble size and shock wave intensity of the FREDDY laser was inversely related to the fiber-to-stone distance over the range tested (0.5 to 3.0 mm).

CONCLUSIONS

While bubble size was noted to increase with a larger stone-to-fiber distance using the holmium laser, to consistently generate cavitation bubbles and shock waves using the FREDDY laser the laser fiber should be operated within 3.0 mm of the target stone. These findings have significant implications during clinical laser stone fragmentation.

Authors+Show Affiliations

Comprehensive Kidney Stone Center, Division of Urologic Surgery, Duke University Medical Center and Pratt School of Engineering, Duke University, Durham, North Carolina 27710, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17382775

Citation

Fuh, Eric, et al. "The Effect of Frequency Doubled Double Pulse Nd:YAG Laser Fiber Proximity to the Target Stone On Transient Cavitation and Acoustic Emission." The Journal of Urology, vol. 177, no. 4, 2007, pp. 1542-5.
Fuh E, Haleblian GE, Norris RD, et al. The effect of frequency doubled double pulse Nd:YAG laser fiber proximity to the target stone on transient cavitation and acoustic emission. J Urol. 2007;177(4):1542-5.
Fuh, E., Haleblian, G. E., Norris, R. D., Albala, W. D., Simmons, N., Zhong, P., & Preminger, G. M. (2007). The effect of frequency doubled double pulse Nd:YAG laser fiber proximity to the target stone on transient cavitation and acoustic emission. The Journal of Urology, 177(4), 1542-5.
Fuh E, et al. The Effect of Frequency Doubled Double Pulse Nd:YAG Laser Fiber Proximity to the Target Stone On Transient Cavitation and Acoustic Emission. J Urol. 2007;177(4):1542-5. PubMed PMID: 17382775.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effect of frequency doubled double pulse Nd:YAG laser fiber proximity to the target stone on transient cavitation and acoustic emission. AU - Fuh,Eric, AU - Haleblian,George E, AU - Norris,Regina D, AU - Albala,W David M, AU - Simmons,Neal, AU - Zhong,Pei, AU - Preminger,Glenn M, PY - 2006/06/22/received PY - 2007/3/27/pubmed PY - 2007/5/1/medline PY - 2007/3/27/entrez SP - 1542 EP - 5 JF - The Journal of urology JO - J Urol VL - 177 IS - 4 N2 - PURPOSE: Scant information has been published describing the effect of laser fiber distance from the stone target on the mechanism of calculus fragmentation. Using high speed photography and acoustic emission measurements we characterized the impact of laser fiber proximity on stone comminution. We evaluated the effect of laser fiber distance from the stone target on resultant cavitation bubble formation and shock wave generation. MATERIALS AND METHODS: Stone fragmentation was assessed using a FREDDY (frequency doubled double pulse Nd:YAG) (World of Medicine, Orlando, Florida) laser and a holmium laser. The FREDDY laser was operated using a 420 microm fiber at an output energy of 120 and 160 mJ in single and double pulse settings, and a pulse repetition rate of 1 Hz. The holmium laser was operated using a 200 microm fiber at an output energy of 1 to 3 J and a pulse repetition rate of 1 Hz. The surface of a 1 cm square BegoStone (Bego, Bremen, Germany) attached to an X-Y-Z translational stage was aligned perpendicular to the laser fiber, which was immersed in a Lucite tank filled with water at room temperature. An Imacon 200 high speed camera was used to capture transient cavitation bubbles at a framing rate of up to 1,000,000 frames per second. Acoustic emission signals associated with shock waves generated during the rapid expansion and collapse of the cavitation bubble were measured using a 1 MHz focused ultrasound transducer. RESULTS: At laser fiber distances of 3.0 mm or less cavitation bubbles and shock waves were observed with the FREDDY laser. In contrast to the holmium laser, the bubble size and shock wave intensity of the FREDDY laser was inversely related to the fiber-to-stone distance over the range tested (0.5 to 3.0 mm). CONCLUSIONS: While bubble size was noted to increase with a larger stone-to-fiber distance using the holmium laser, to consistently generate cavitation bubbles and shock waves using the FREDDY laser the laser fiber should be operated within 3.0 mm of the target stone. These findings have significant implications during clinical laser stone fragmentation. SN - 0022-5347 UR - https://www.unboundmedicine.com/medline/citation/17382775/The_effect_of_frequency_doubled_double_pulse_Nd:YAG_laser_fiber_proximity_to_the_target_stone_on_transient_cavitation_and_acoustic_emission_ L2 - https://www.jurology.com/doi/10.1016/j.juro.2006.11.078?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -