Laser Tissue Interaction, November 28 th, 2016 Lasers in Urology Qureshi, Muhammad Mohsin Gwangju Institute of Science and Technology Biomedical in vivo Opto-scopy Laboratory
2 Content Introduction to urology & laser Laser treatment External genital Urethra Bladder Ureter
Introduction to Urology & laser Urology deals with the medicine that focus on surgical and medical diseases of male and female urinary tract system and the male reproductive organ. Commonly used lasers in urology are: CO 2 laser λ=10,600nm Nd:YAG laser λ=1064nm KTP laser λ=532nm Ho:YAG laser λ=2,100nm
Introduction to Urology & laser Urological laser treatment covers the: external genital lower urinary fact (urethra) bladder upper urinary tract (ureter) prostate kidneys
Laser treatment: external genital 5 Condylomata acuminata is the most frequent genital warts caused by human papillomavirus (HPV) infection which usually sexually transmitted disease leading to anogenital lesions. These genital warts can be treated by Nd:YAG or CO 2 lasers
Laser treatment: external genital 6 At initial stage of genital cancer can be treated well by Nd:YAG laser but if the tumor is in the advanced stage then it should be extirpated mechanically and the remain tissues coagulated by Nd:YAG laser. However, de Lima et al. (2015) shows the treatment of genital lesions with diode laser vaporization.
Laser treatment: external genital 7 de Lima et al. BMC Urology (2015) 15:39
Laser treatment: lower urinary tract 8 The narrowing of blood vessel in the lower urinary tract due to inflammation, tumor growth, or any origin can be treated by a surgery called urethrotomy. Wieland et al. (1993) first report the use of Ho:YAG laser and then afterward Nicolai et al. (1995) conclude that the occurence of laserinduced restenosis is approximately 10% only.
Laser treatment: lower urinary tract 9 Holmium:YAG laser is a pulsed solid state laser with λ 2140nm, strongly absorbed by water. Interestingly absorbed into prostate tissue to 0.4mm depth. Heat created by Ho:YAG laser (>100 o C) causes good vaporization with coagulation of small to medium sized vessels.
Laser treatment: lower urinary tract 10
Laser treatment: lower urinary tract 11
Laser treatment: bladder 12 Urinary bladder is a muscular sac in the pelvis, just above and behind the pubic bone. Tumors of the bladder are very difficult to treat because tumor can easily break through the bladder wall. http://www.webmd.com/urinary-incontinence-oab/picture-of-the-bladder
13 Laser treatment: bladder Frank et al. (1982) compared CO 2 and Nd:YAG lasers for bladder tissue, and conclude that Nd:YAG laser performed well because of coagulating the bladder tumors. While Argon ion lasers are applicable only in superficial bladder tumor. Several reports suggest the superiority of laser method over Transurethral Resection (TUR)
Laser treatment: bladder 14 Wei Wang et al. (2016) conducted a review of basic thulium laser physics and laser en bloc resection and summarized the current clinical literature. Nowadays, Ho-YAG and thulium lasers are used in bladder tumor treatment, in which Ho:YAG laser used in pulsed mode while thulium laser used in the continuous mode which does not exhibit tissue-tearing, therefore, thulium laser used for en bloc resection.
Laser treatment: bladder 15 PDT has been used in the treatment of bladder cancer, since it enables the resection of tumors which are not visible otherwise. Laser-induced fluorescence and treatment of cancer is one of the main advantage of using PDT.
16 Laser treatment: ureter Lithotripsy of urinary calculi is a procedure in which ultrasound waves are used to break up the stones in the urethra. Then, in 1980s Nd:YAG lasers [Watson et al. (1980)], and dye lasers [Hofstetter et al. (1986)] were used. But nowadays Holmium YAG lasers are commonly used in the urinary calculi surgery.
17 Laser treatment: ureter Advantages of Ho:YAG laser in lithotripsy Can transmit energy through flexible fiber Able to fragment all stones regardless of composition Produces significantly smaller fragments Produces weak shockwave and less retropulsion
18 Laser treatment: ureter Disadvantages of Ho:YAG laser in lithotripsy Initial high cost of device and laser fiber Potential side effect is production of cyanide when uric acid stones are treated But a review of clinical experience Teichman et al. (1998) suggests no toxicity from Ho:YAG laser.
Laser treatment: ureter 19
Laser treatment: prostate 20 When YAG laser shine through a (Potassium- Titanyl-Phosphate) KTP crystal, it doubles the frequency and halves the emitted wavelength to 532nm which is on the green part of the visible spectrum. KTP laser strongly absorbed by hemoglobin and poorly absorbed by water/saline
Laser treatment: prostate 21 Prostate is very sensitive organ embraces the urethra. Common disease is Benign Prostatic Hyperplasia (BPH) causing problems with urinating.
22 Laser treatment: prostate Nd:YAG laser was used on tumors of the prostate by Bӧwering et al. (1979). Then, in 1990s two most popular techniques were introduce Transurethral ultrasound-guided laserinduced prostatectomy (TULIP) Laser-induced interstitial thermotherapy (LITT)
23 Laser treatment: prostate Many other prostectomy were evolved during 1990s, like Visual Laser Abelation of the Prostate (VLAP). Side firing systems mirror to reflect or a prism to refract the laser at various angle in the prostatic or urethra were introduced.
Laser treatment: prostate 24 Endoscopic diagnosis and treatment in prostate pathology by Petrisor Aurelian Geavlete
Laser treatment: prostate 25 In TULIP the positioning of 90 o prism inside the urethra can control the ultrasound. But it causes hyperthermia i.e., temperature raise to 45 o C which is not sufficient in treating BPH. Therefore, LITT technique used in BPH
Laser treatment: prostate 26 Laser-Induced Interstitial Thermo Therapy (LITT): Minimally invasive surgery In LITT a laser applicator inside the tissue (tumor) to be coagulated to cause tumor necrosis by heating cells above 60 o C
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