Procedure for the computation of hazards from diffusely scattering surfaces under the Z136.1-2000 American National Standard for Safe Use of Lasers

Abstract

The current national consensus standard for laser safety in the United States is the American National Standard for Safe Use of Lasers (ANSI Z136.1). The most recent standard, Z136.1-2000, incorporates a wealth of recent bioeffects data and established a number of new maximum permissible exposure (MPE) limits for laser safety. The standard also includes recent procedures for the computation of MPE values from large or extended diffusely scattering sources, which must be understood by health physicists, laser safety officers, and others in the field of occupational safety. Here we present the fourth in a series of tutorial articles, written to clarify laser safety analysis procedures under this standard, with an emphasis on the MPE computation methods related to extended sources, and the determination of nominal hazard zones.

Lanthanide-doped upconversion nano-bioprobes: electronic structures, optical properties, and biodetection

“…Currently, the commercial CW diode laser is the most frequently used excitation source for Ln 3+ -doped UCNPs. However, CW excitation at safe power densities within ANSI standards gives rise to a low UC QY for UCNPs, 251 which limits most of their potential bioapplications. One opportunity to break through the low power density restriction of UC emissions while suppressing thermal effects of the excitation light is employing pulse excitation.…”

Lanthanide-doped upconversion nanoparticles electrostatically coupled with photosensitizers for near-infrared-triggered photodynamic therapy

“…To avoid any tissue damage induced by the heating effect of the laser irradiation, the laser treatment was done with a 5 min interval for every 1 min of irradiation and the laser power density used here (0.5 W cm À2 ) is well below the conservative limit set for human skin exposure to 980 nm NIR light (0.7 W cm À2 ). 52 Mice that received intratumoral injection of UCNP-ZnPc-COOH without subsequent laser exposure were applied as control. The in vivo PDT efficacy of UCNP-ZnPc-COOH was then assessed by measuring the tumor volumes over a period of 2 weeks.…”

Development of “smart” drug delivery systems for chemo/PDT synergistic treatment

“…161 In fact, the American National Standard for Safe Use of Lasers recommends that the maximum permissible exposure at 808 nm be 0.33 W cm À2 . 162 Although many nanomedicines have the potential to enhance drug delivery, reduce side effects, and improve therapeutic efficiency, only a few nanosystems have entered clinical application, whereas the majority of smart chemo/PDT synergistic nanoplatforms have been limited to proof-of-concept and academic research. Despite the progress made, significant obstacles remain in the clinical translation process, and a great deal of work is required to overcome these difficulties and bring the product to market.…”

“…161 In fact, the American National Standard for Safe Use of Lasers recommends that the maximum permissible exposure at 808 nm be 0.33 W cm −2 . 162…”