Analysis of opto-thermal interaction of porcine stomach tissue with 808-nm laser for endoscopic submucosal dissection

Abstract

In endoscopic submucosal dissection (ESD), the narrow gastrointestinal space can cause di±culty in surgical interventions. Tissue ablation apparatuses with high-power CO 2 lasers or Nd:YAG lasers have been developed to facilitate endoscopic surgical procedures. We studied the interaction of 808-nm laser light with a porcine stomach tissue, with the aim of developing a therapeutic medical device that can remove lesions at the gastrointestinal wall by irradiating a near-infrared laser light incorporated in an endoscopic system. The perforation depths at the porcine¯llet and the stomach tissues linearly increased in the range of 2-8 mm in proportion to the laser energy density of 63.7-382 kJ/cm 2 . Despite the distinct structural and compositional di®erence, the variation of the perforation depth between the stomach and the¯llet was not found at 808-nm wavelength in our measurement. We further studied the laser-tissue interaction by changing the concentration of the methyl blue solution used conventionally as a submucosal°u idic cushion (SFC) in ESD procedures. The temperature of the mucosal layer increased more rapidly at higher concentration of the methyl blue solution, because of enhanced light absorption at the SFC layer. The insertion of the SFC would protect the muscle layer from thermal damage. We con¯rmed that more e®ective laser treatment should be enabled by tuning the opto-thermal properties of the SFC. This study can contribute to the optimization of the driving parameters for laser incision techniques as an alternative to conventional surgical interventions.

Measurement method for incisions ablated by femtosecond laser in biological soft tissues

“…Lasers have been widely used in large-scale surgical operations due to their high precision and low pain in surgical cutting and lesion resection [1] . They have been used for the cutting of body super cial soft tissues [2] , stomach [3] , kidney [4][5][6] , liver [7,8] , as well as for the resection of polyps and tumors [9] . In laser surgery, both cutting and resection require precise control of the incision dimension.…”

Study of the Changes of Gastric Wall Mucosa Optical Properties under the Impact of Aqueous Solutions of Haemoglobin and Glucose for Improving Conditions of the Laser Coagulation

“…The contactless laser coagulation and ablation of pathologic formations in different organs is widely used in modern clinics [1][2][3][4][5][6][7][8]. The minor invasiveness of the procedure reduces the risk of postoperative complications.…”

“…The minor invasiveness of the procedure reduces the risk of postoperative complications. The sources used for this purpose include, particularly, the ytterbium (1075 nm) [3], СО2 (9.4-10.6 µm) [5], Nd:YAG (1064 nm) [1,4], diode (980, 808, 810 nm) [2,6,7], and other lasers. The main advantage of lasers generating at the wavelengths that coincide with the absorption bands of water is the small depth of light penetration into tissues, which prevents the damage of the adjacent healthy tissue, underlying the affected area [5,8].…”