environmental, industrial processing, food safety, forensic and biological. Commercial instruments are available for all markets to measure every element and isotope within a sample. Some instruments combine both optical and mass detection to extend the analysis coverage, and dynamic range in sensitivity. Biology Laser ablation is used in science to destroy nerves and other tissues to study their function. For example, a species of pond snail, Helisoma trivolvis, can have their sensory neurons laser ablated off when the snail is still an embryo to prevent use of those nerves. Another example is the trochophore larva of Platynereis dumerilii, where the larval eye was ablated and the larvae was not phototactic, anymore. However phototaxis in the nectochaete larva of Platynereis dumerilii is not mediated by the larval eyes, because the larva is still phototactic, even if the larval eyes are ablated. But if the adult eyes are ablated, then the nectochaete is not phototactic anymore and thus phototaxis in the nectochaete larva is mediated by the adult eyes. Laser ablation can also be used to destroy individual cells during embryogenesis of an organism, like Platynereis dumerilii, to study the effect of missing cells during development. Medicine There are several laser types used in medicine for ablation, including argon, carbon dioxide (CO2), dye, erbium, excimer, Nd:YAG, and others. Laser ablation is used in a variety of medical specialties including ophthalmology, general surgery, neurosurgery, ENT, dentistry, oral and maxillofacial surgery, and veterinary. Laser scalpels are used for ablation in both hard- and soft-tissue surgeries. Some of the most common procedures where laser ablation is used include LASIK, skin resurfacing, cavity preparation, biopsies, and tumor and lesion removal. In soft-tissue surgeries, the CO2 laser beam ablates and cauterizes simultaneously, making it the most practical and most common soft-tissue laser. Laser ablation can be used on benign and malignant lesions in various organs, which is called laser-induced interstitial thermotherapy. The main applications currently involve the reduction of benign thyroid nodules and destruction of primary and secondary malignant liver lesions. Laser ablation is also used to treat chronic venous insufficiency. See also ablative brain surgery. See also Dental laser Laser induced breakdown spectroscopy LASEK LASIK Laser bonding Laser cutting Laser engraving Laser scalpel Laser surgery Soft-tissue laser surgery List of laser articles Matrix-assisted laser desorption/ionization Parts cleaning Optical breakdown photoionization mode (OB) at Photoionization mode Soft retooling References Bibliography Oxford Concise Medical Dictionary,2002,6th edition, Ablation Laser