Copyright
©The Author(s) 2001.
World J Gastroenterol. Jun 15, 2001; 7(3): 317-323
Published online Jun 15, 2001. doi: 10.3748/wjg.v7.i3.317
Published online Jun 15, 2001. doi: 10.3748/wjg.v7.i3.317
Table 1 Laser effects used in gastroenterology
Laser effect | Clinical use |
High power thermal: | Haemostasis |
Cutting or debulking of tissue by vaporisation and coagulation | |
Low power thermal: (Interstitial laser photocoagulation, ILP) | Gentle coagulation of lesions within solid organs |
Photochemical: (Photodynamic therapy, PDT) | Non-thermal destruction of tissue by activation of a previously administered photosensitising drug |
Pulsed shock wave | Fragmentation of gall stones |
Table 2 Comparison of modalities for palliation of malignant dysphagia
Laser | Conventional stent | Self expanding metal stent | |
Technique | Basically safe (risk of perforation if dilatation also needed) | 10% risk of perforation on insertion | Usually safe and easy to insert |
Cost | High setup cost Low patient costs | Low cost | High cost |
Contra | Fistula | High lesion | High lesion |
indications | No endoscopic target | Tracheal compression | Tracheal compression Care with lesions crossing cardia |
Dysphagia post | Variable, can be | Semi-solids | Variable, can be |
therapy | close to normal | some solids | close to normal |
Repeat Therapy | Possible. Usually required after 6-8 weeks | Stent can be adjusted | Difficult to adjust once inserted. Second stent or laser debulking for tumour overgrowth |
Enhancement of | Yes | No | No |
dysphagia relief with radiotherapy |
Table 3 Comparison of interstitial laser photocaogulation (ILP) and photodynamic therapy (PDT)
ILP | PDT | |
Nature of biological effect | Thermal | Photochemical |
Wavelength of light used | Infrared (805-1064 nm) | Green (510-530 nm) Red (630-675 nm) |
Typical laser power per fibre | 3-5 W | 0.1-0.3 W (higher for illuminating hollow organs) |
Effect on connective tissue | Destroyed | Largely unaffected |
Healing | Resorption and scarring, some regeneration | Regeneration, sometimes with scarring |
Selectivity of necrosis between tissue of origin of tumour and other adjacent tissues | None | Possible between mucosa and underlying muscle in hollow organs |
Selectivity of necrosis between tumour and tissue of origin of tumour | None | Minimal |
Cumulative toxicity | None | None |
Table 4 Potential targets for photodynamic therapy in gastroenterology
Small, inoperable tumours in endoscopically accessible sites |
Areas of dysplasia, especially in Barrett's oesophagus |
Localised pancreatic cancer |
Bile duct cancer |
As an adjunct to surgery |
Palliation of advanced cancers-controversial |
Eradication of Helicobacter pylori-speculative |
- Citation: Lovat LB, Bown SG. Lasers in gastroenterology. World J Gastroenterol 2001; 7(3): 317-323
- URL: https://www.wjgnet.com/1007-9327/full/v7/i3/317.htm
- DOI: https://dx.doi.org/10.3748/wjg.v7.i3.317