title: Characterization of size-specific particulate matter emission rates for a simulated medical laser procedure--a pilot study.
abstract: Prior investigation on medical laser interaction with tissue has suggested device operational parameter settings influence laser generated air contaminant emission, but this has not been systematically explored. A laboratory-based simulated medical laser procedure was designed and pilot tested to determine the effect of laser operational parameters on the size-specific mass emission rate of laser generated particulate matter. Porcine tissue was lased in an emission chamber using two medical laser systems (CO2, λ = 10,600 nm; Ho:YAG, λ = 2100 nm) in a fractional factorial study design by varying three operational parameters (beam diameter, pulse repetition frequency, and power) between two levels (high and low) and the resultant plume was measured using two real-time size-selective particle counters. Particle count concentrations were converted to mass emission rates before an analysis of variance was used to determine the influence of operational parameter settings on size-specific mass emission rate. Particle shape and diameter were described for a limited number of samples by collecting particles on polycarbonate filters, and photographed using a scanning electron microscope (SEM) to examine method of particle formation. An increase in power and decrease in beam diameter led to an increase in mass emission for the Ho:YAG laser at all size ranges. For the CO2 laser, emission rates were dependent on particle size and were not statistically significant for particle ranges between 5 and 10 µm. When any parameter level was increased, emission rate of the smallest particle size range also increased. Beam diameter was the most influential variable for both lasers, and the operational parameters tested explained the most variability at the smallest particle size range. Particle shape was variable and some particles observed by SEM were likely created from mechanical methods. This study provides a foundation for future investigations to better estimate size-specific mass emission rates and particle characteristics for additional laser operational parameters in order to estimate occupational exposure, and to inform control strategies.
authors.affiliation: 1.Department of Environmental Health Science, Richard M. Fairbanks School of Public Health, Indiana University, 714 N. Senate Ave., Indianapolis, IN 46202, USA lopezram@iu.edu.
authors.forename: Ramon
authors.initials: R
authors.lastname: Lopez
authors.affiliation: 1.Department of Environmental Health Science, Richard M. Fairbanks School of Public Health, Indiana University, 714 N. Senate Ave., Indianapolis, IN 46202, USA.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Lacey
authors.affiliation: 2.Division of Environmental and Occupational Health Sciences, School of Public Health, University of Illinois at Chicago, 2121 W. Taylor St., Chicago, IL 60612, USA.
authors.forename: Julia F
authors.initials: JF
authors.lastname: Lippert
authors.affiliation: 3.Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, 1603 W. Taylor St., Chicago, IL 60612, USA.
authors.forename: Li C
authors.initials: LC
authors.lastname: Liu
authors.affiliation: 2.Division of Environmental and Occupational Health Sciences, School of Public Health, University of Illinois at Chicago, 2121 W. Taylor St., Chicago, IL 60612, USA.
authors.forename: Nurtan A
authors.initials: NA
authors.lastname: Esmen
authors.affiliation: 2.Division of Environmental and Occupational Health Sciences, School of Public Health, University of Illinois at Chicago, 2121 W. Taylor St., Chicago, IL 60612, USA.
authors.forename: Lorraine M
authors.initials: LM
authors.lastname: Conroy
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D000818:Animals; D004784:Environmental Monitoring / Q000379:methods; D005740:Gases / Q000737:chemistry; D053685:Laser Therapy / Q000295:instrumentation* / Q000379:methods; D008855:Microscopy, Electron, Scanning; D016273:Occupational Exposure / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D010865:Pilot Projects; D012906:Smoke; D013552:Swine
chemical_list: D000395:Air Pollutants, Occupational; D005740:Gases; D052638:Particulate Matter; D012906:Smoke
keywords: emission rate; laser generated particulate matter; medical laser; particulate matter; scanning electron microscopy; size-selective air sampling