Can daylight-PDT be performed indoor?
Level 5 - mechanism / opinion, no new human data
Narrative review discussing technical parameters and indoor illumination alternatives for photodynamic therapy without primary human trial data.
PubMed 29417802 · doi:10.23736/S0392-0488.18.05907-2
What was done
The authors reviewed technical thresholds and delivery methods for natural daylight-mediated photodynamic therapy (NDL-PDT) in thin actinic keratosis, evaluating indoor alternatives such as greenhouses, ceiling-mounted lamp arrays, surgical theatre lights, and dedicated white LED sources (simulated daylight PDT or artificial white light PDT).
What was found
Effective NDL-PDT requires a minimum light dose of 4 J/cm² over a 2-hour treatment duration at a minimum temperature of 10 °C, corresponding to a minimum illuminance of 11,000 lux. Overcast midday conditions can yield 20,000 lux, while bright sunlight reaches 110,000 lux. Due to weather and seasonal temperature limitations at certain latitudes, indoor systems utilizing white LEDs or overhead lamps can reliably achieve the necessary illumination dose. No primary clinical efficacy numbers or patient outcomes were reported in the abstract.
Why it matters
While natural daylight PDT improves tolerability and reduces treatment cost compared to conventional PDT, weather dependency limits its reliability. Defining indoor artificial light alternatives enables consistent, year-round treatment delivery independent of climate.
Limits
The abstract reports no primary clinical study, patient cohort, sample size, or quantitative clearance rates. Comparative efficacy, adverse event rates, and standardized protocols across diverse artificial light sources were not measured in the provided text.
Cited by
- supports Driving horizontally inside a car or standing outside on a cloudy day provides between 5,000 and 10,000 lux of light.