Use of illuminance as a guide to effective light delivery during daylight photodynamic therapy in the U.K.

O’Mahoney, Paul; Khazova, Marina; Higlett, Michael; Lister, Tom; Ibbotson, Sally H.; Eadie, Ewan

doi:10.1111/bjd.15146

Cited by 25 publications

(34 citation statements)

References 21 publications

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“…Most investigations of daylight PDT report light dose as the effective fluence, which is the fluence weighted by the PpIX absorption spectrum (4,6,14,(16)(17)(18). So, even though the total irradiance of indoor daylight is 75% of its outdoor counterpart, the PpIX-weighted effective irradiance indoors is 60% of the outdoor complement because more UV light is blocked by the window (Fig.…”

Section: Resultsmentioning

confidence: 99%

Weather‐informed Light–tissue Model–Based Dose Planning for Indoor Daylight Photodynamic Therapy

LaRochelle

Chapman

Maytin

et al. 2019

Photochem & Photobiology

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Daylight activation for photodynamic therapy (PDT) of skin lesions is now widely adopted in many countries as a less painful and equally effective treatment mechanism, as compared to red or blue light activation. However, seasonal daylight availability and transient weather conditions complicate light dose estimations. A method is presented for dose planning without placing a large burden on clinical staff, by limiting spectral measurements to a one‐time site assessment, and then using automatically acquired weather reports to track transient conditions. The site assessment tools are used to identify appropriate treatment locations for the annual and daily variations in sunlight exposure for clinical center planning. The spectral information collected from the site assessment can then be integrated with real‐time daily electronic weather data. It was shown that a directly measured light exposure has strong correlation (R2: 0.87) with both satellite cloud coverage data and UV index, suggesting that the automated weather indexes can be surrogates for daylight PDT optical dose. These updated inputs can be used in a dose‐planning treatment model to estimate photodynamic dose at depth in tissue. A simple standardized method for estimating light dose during daylight‐PDT could help improve intersite reproducibility while minimizing treatment times.

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Section: Resultsmentioning

confidence: 99%

Weather‐informed Light–tissue Model–Based Dose Planning for Indoor Daylight Photodynamic Therapy

LaRochelle

Chapman

Maytin

et al. 2019

Photochem & Photobiology

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“…Moreover, these two PpIX-weighted metrics are increasingly used in most recent papers. 10,[17][18][19] Assuming spectral irradiances with constant shapes but different amplitudes, the ratio between two PpIX-weighted irradiances is equal to the ratio between the two corresponding irradiances. As a result, irradiances could be converted into PpIX-weighted irradiances by applying the rule of three to data reported in a recent study.…”

Section: Irradiance and Ppix-weighted Irradiancementioning

confidence: 99%

Photodynamic therapy for actinic keratosis of the forehead and scalp with the Aktilite CL 128: Is there a cut‐off value for PpIX‐weighted irradiance for effective treatment?

Vicentini

Vignion‐Dewalle

Thecua

et al. 2019

Photoderm Photoimm Photomed

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Background/purpose: Photodynamic therapy (PDT) is an established treatment for actinic keratosis (AK). Among the approved protocols in Europe, the most widely used involves irradiation with the Aktilite CL 128 (C-PDT). We aimed to assess the heterogeneity of irradiance over the treatment area when using C-PDT. We also investigated whether there is a cut-off value for protoporphyrin IX (PpIX)-weighted irradiance that may predict the treatment outcome of C-PDT.Methods: An Ophir PD300 photodiode sensor connected to an Ophir Laser Star power meter was used to measure the irradiance delivered to 114 AKs of the scalp and forehead of 19 patients treated with C-PDT. The PpIX-weighted irradiances were deduced and cross-referenced with the complete responses at 3 months.Results: From the measured irradiances ranging from 0.25 to 60 mW/cm 2 (average: 31.94 mW/cm 2 ), a standard deviation of 17.17 mW/cm 2 was computed. Irradiance heterogeneity over the treatment area during C-PDT was demonstrated. The 66/114AKs with a complete response at 3 months (57.89%) received a mean PpIX-weighted irradiance of 0.52 mW/cm 2 vs 0.56 mW/cm 2 for the resistant 48/114 AKs (42.11%).No significant effect of PpIX-weighted irradiance on the complete response at 3 months was found (odds ratio for a 0.1-unit change, 0.96; 95% confidence interval, 0.83 to 1.10; P = 0.53). Therefore, no cut-off value for PpIX-weighted irradiance that predicts treatment outcome could be identified. Conclusions:A device enabling homogeneous irradiation at a lower irradiance than the Aktilite CL 128 may therefore be suitable. This lower irradiance may further increase the treatment tolerance by patients. K E Y W O R D S actinic keratosis, Aktilite CL 128, complete response, photodynamic therapy, PpIX-weighted irradiance | 233 VICENTINI ET al.

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“…This issue of the BJD includes an interesting study by O'Mahoney et al . on daylight photodynamic therapy (dPDT), which has recently evolved as a new treatment option for patients with chronic sun damage suffering from field cancerization with grade 1–2 actinic keratoses (AKs) on the scalp and face, with equal success rates compared with conventional PDT (cPDT) but with several striking advantages …”

mentioning

confidence: 99%

“…To overcome these challenges, O'Mahoney et al . give simple guidance on when and how dPDT can safely be performed in the U.K. and Northern Ireland during the year.…”

mentioning

confidence: 99%

“…At our Department of Dermatology in Graz, Austria (latitude 47°4′ 52·9″ and longitude 15°27′ 49·8″) on 15 November 2016, although outside temperature was only 3 °C, behind window glass we measured an illuminance of 52 000 lux at 10 o'clock in the morning. According to the equations presented by O'Mahoney et al ., we calculated for an exposure time of 2 h, a PpIX‐weighted effective dose of 19·45 J cm −2 (Equation 1) and 18·76 J cm −2 (Equation 2, corrected for the geographic location and time of the year), which is well above the aforementioned required 4 J cm −2 . Thus, on this day, we could even perform ‘conservatory – behind window glass’ dPDT in our patient with high confidence.…”

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confidence: 99%

See 1 more Smart Citation

Daylight photodynamic therapy: where and when is it possible?

Legat

Wolf

2017

Br J Dermatol

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Use of illuminance as a guide to effective light delivery during daylight photodynamic therapy in the U.K.

Cited by 25 publications

References 21 publications

Weather‐informed Light–tissue Model–Based Dose Planning for Indoor Daylight Photodynamic Therapy

Weather‐informed Light–tissue Model–Based Dose Planning for Indoor Daylight Photodynamic Therapy

Photodynamic therapy for actinic keratosis of the forehead and scalp with the Aktilite CL 128: Is there a cut‐off value for PpIX‐weighted irradiance for effective treatment?

Daylight photodynamic therapy: where and when is it possible?

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