In endoscopic submucosal dissection(ESD),the narrow gastrointestinal space can cause difficulty in surgical interventions.Tissue ablation apparatuses with high-power CO_(2) lasers or Nd:YAG lasers have been developed ...In endoscopic submucosal dissection(ESD),the narrow gastrointestinal space can cause difficulty 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 fillet and the stomach tissues linearly increased in the range of 2–8mm 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 fillet 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 fluidic 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 confirmed that more effective 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.展开更多
Molecules such as water,proteins and lipids that are contained in biological tissue absorb mid-infrared(MR)light,which allows such light to be used in laser surgical treatment.Esters,amides and water exhibit strong ab...Molecules such as water,proteins and lipids that are contained in biological tissue absorb mid-infrared(MR)light,which allows such light to be used in laser surgical treatment.Esters,amides and water exhibit strong absorption bands in the 5-7μm wavelength range,but at present there are no lasers in clinical use that can emit in this range.Therefore,the present study focused on thequantum cascade laser(QCL),which is a new type of semiconductor laser that can emit at MIRwavelengths and has recentiy achieved high output power.A high-power QCL with a peakwavelength of 5.7μm was evaluated for use as a laser scalpel for ablating biological soft tissue.The interaction of the laser beam with chicken breast tissue was compared to a conventional CO_(2) laser,based on surface and cross-sectional images.The QCL was found to have sufficient power to ablate soft tissue,and its coagulation,carbonization and ablation effects were similar to those forthe CO_(2) laser.The QCL also induced comparable photothermal effects because it acted as apseudo-continuous wave laser due to its low peak power.A QCL can therefore be used as an effective laser scalpel,and also offers the possibility of less invasive treatment by targeting specificabsorption bands in t he MIR region.展开更多
基金This study was supported by grants from the Industrial Core Technology Development Program (10047904)the Industrial Strategic Technology Development Program (10049743) of the Korea Evaluation Institute of Industrial Technology(KEIT)the Human Resources Development Program (20134010200580)of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)funded by the Ministry of Trade,Industry and Energy,Republic of Korea.
文摘In endoscopic submucosal dissection(ESD),the narrow gastrointestinal space can cause difficulty 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 fillet and the stomach tissues linearly increased in the range of 2–8mm 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 fillet 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 fluidic 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 confirmed that more effective 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.
基金supported by JSPS KAKENHI Grant Number 24241209.
文摘Molecules such as water,proteins and lipids that are contained in biological tissue absorb mid-infrared(MR)light,which allows such light to be used in laser surgical treatment.Esters,amides and water exhibit strong absorption bands in the 5-7μm wavelength range,but at present there are no lasers in clinical use that can emit in this range.Therefore,the present study focused on thequantum cascade laser(QCL),which is a new type of semiconductor laser that can emit at MIRwavelengths and has recentiy achieved high output power.A high-power QCL with a peakwavelength of 5.7μm was evaluated for use as a laser scalpel for ablating biological soft tissue.The interaction of the laser beam with chicken breast tissue was compared to a conventional CO_(2) laser,based on surface and cross-sectional images.The QCL was found to have sufficient power to ablate soft tissue,and its coagulation,carbonization and ablation effects were similar to those forthe CO_(2) laser.The QCL also induced comparable photothermal effects because it acted as apseudo-continuous wave laser due to its low peak power.A QCL can therefore be used as an effective laser scalpel,and also offers the possibility of less invasive treatment by targeting specificabsorption bands in t he MIR region.
