From the Guidelines
For 5-aminolevulinic acid (5-ALA) activation, the recommended light dose is typically 10 J/cm² for blue light and 75 J/cm² for red light, as supported by the most recent guidelines from 2021 1, 2, 3. The difference in energy requirements relates to the absorption spectrum of protoporphyrin IX (PpIX), the photoactive metabolite of 5-ALA, which has a strong absorption peak in the blue spectrum but requires higher energy in the red spectrum to achieve similar photodynamic effects. Some key points to consider when applying these light doses include:
- Using appropriate light sources with consistent output
- Protecting surrounding tissues from unnecessary exposure
- The activation process works by generating reactive oxygen species that selectively damage abnormal cells that have accumulated higher concentrations of PpIX
- Blue light is more commonly used for dermatological applications like photodynamic therapy for actinic keratosis or superficial basal cell carcinoma
- Red light penetrates deeper tissues and is often used for neurosurgical applications like fluorescence-guided resection of malignant gliomas It's also important to note that the specific light dose may vary depending on the individual patient and the specific application, and should be determined based on the most recent and highest quality evidence available, such as the guidelines from 2021 1, 2, 3.
From the Research
Joules per Centimeter (J/cm) for Blue and Red Light Activation of 5-aminolevulinic acid (5-ALA)
- The joules per centimeter (J/cm) for blue and red light activation of 5-aminolevulinic acid (5-ALA) can be found in several studies:
+ Red light:
- 50 J/cm2 was used in a study on the treatment of actinic keratosis with topical 5-aminolevulinic acid 4
- 10 to 150 J/cm2 was used in a study on photodynamic therapy of actinic keratosis with topical 5-aminolevulinic acid 4
- 150 J/cm2 was used in a study on photodynamic therapy with topical application of 5-aminolevulinic acid in the treatment of actinic keratoses 5 + Blue light:
- No specific joules per centimeter (J/cm) values for blue light activation of 5-ALA were found in the provided studies
- However, a study on dual wavelength 5-aminolevulinic acid photodynamic therapy used a combination of 405-nm and 505-nm wavelength, but did not specify the joules per centimeter (J/cm) value 6
- Another study used intense pulsed light (IPL) with fluences of 20, 25, 40, and 50 J/cm2, but did not specify the wavelength 7
Wavelengths Used in Studies
- The wavelengths used in the studies include: + 410 nm, 510 nm, 545 nm, 580 nm, and 630 nm, which are the absorption wavelength peaks of protoporphyrin IX (PpIX) 6 + 405-nm and 505-nm wavelength combination, which was found to be the most effective in a study on dual wavelength 5-aminolevulinic acid photodynamic therapy 6 + 580-740 nm, which was used in a study on photodynamic therapy with topical application of 5-aminolevulinic acid in the treatment of actinic keratoses 5 + 630 nm, which was used in a study on photodynamic therapy of actinic keratosis with topical 5-aminolevulinic acid 4