Light-Emitting Diodes: A Novel Light Source for Phototherapy

Abstract

High intensity light-emitting diodes (LEDs) are being studied as possible light sources for the phototherapy of hyperbilirubinemic neonates. These power-efficient, low heat-producing light sources have the potential to deliver high intensity light of narrow wavelength band in the blue-green portion of the visible light spectrum, which overlaps the absorption spectrum of bilirubin (BR). We compared the efficacy between single LEDs of different color and then constructed a prototype phototherapy device using 300 blue LEDs. The efficacy of this device was compared with that of conventional phototherapy devices by measuring the in vitro photodegradation of BR in human serum albumin. When blue, blue-green, green, and white LEDs were compared, the blue light was the most effective in degrading BR by 28% of dark control, followed by blue-green (18% of control), and then white light (14% of control). Green light was the least effective (11% of control). The prototype device with three focused arrays, each with 100 blue LEDs, generated greater irradiance (> 200 microW.cm-2.nm-1) than any of the conventional devices tested. It also supported the greatest rate of BR photodegradation. We conclude that light from LEDs should be considered a more effective treatment for hyperbilirubinemia than light from presently used phototherapy devices. Furthermore, the unique characteristics of this light source may make it especially suitable for use in safe and lightweight home phototherapy devices.

A Prospective Randomized Controlled Study of Phototherapy Using Blue and Blue-Green Light-Emitting Devices, and Conventional Halogen-Quartz Phototherapy

“…Although this difference did not reach statistical significance, the lower efficacy of blue-green phototherapy is consistent with our recent in vitro observations. 11 We compared the in vitro efficacy of LEDs and found that blue light was the most effective in degrading bilirubin by 28% of dark control, followed by blue-green (18% of control), and then white light (14% of control). Green light was the least effective (11% of control).…”

“…In this study, it was decided to compare blue-green LEDs, rather than green LEDs, to blue LEDs and conventional halogen-quartz lamps, in accordance with our previous in vitro efficacy studies. 11 Furthermore, Donzelli et al 9 presented preliminary data suggesting that a unique narrow-spectrum blue-green fluorescent lamp with a peak emission at 480 nm was more effective than Special Blue lamps. The high phototherapeutic efficiency of blue-green light was attributed to the combined effects of the increase from blue to green of the quantum yield, of lumirubin, responsible for the quickest pigment clearance in newborns.…”

“…11 This device has a narrow luminous spectrum, and therefore allows for the first time to compare blue (peak 459 nm) versus blue-green (peak 505 nm) phototherapy.…”

Heme Regulation in Traumatic Brain Injury: Relevance to the Adult and Developing Brain

“…It should be noted, however, that tin protoporphyrin and other metalloporphyrins are not only differential inhibitors of HO-1 and HO-2 (Vreman et al, 1998), but have also been reported to inhibit the activity of cytochrome P450s, nitric oxide synthase, soluble guanylate cyclase, and others (Appleton et al, 1999;Grundemar and Ny, 1997;Luo and Vincent, 1994;Meffert et al, 1994;Murray, 1997). They have also been reported to be direct inhibitors of lipid peroxidation (Imai et al, 1990;Wong et al, 2000).…”

Intravenous Immunoglobulin G Treatment in ABO Hemolytic Disease of the Newborn, is it Myth or Real?

“…High intensity phototherapy (spectral irradiance higher than 30 lW/cm 2 /nm, 430-490 nm band) delivered as close as infants surface is effective in reducing serum unconjugated bilirubin levels and need for exchange transfusion [4]. When compared with conventional phototherapy, LED lights are more effective in reducing serum unconjugated bilirubin levels [18]. In our study all patients were treated with LEDs, low rates of erythrocyte transfusion and no need for exchange transfusions might be due to this new advanced phototherapy method regardless of IVIG.…”