Abstract
Monitoring the onset of erythema following external beam radiation therapy has the potential to offer a means of managing skin toxicities via biological targeted agents - prior to full progression. However, current skin toxicity scoring systems are subjective and provide at best a qualitative evaluation. Here, we investigate the potential of diffuse optical spectroscopy (DOS) to provide quantitative metrics for scoring skin toxicity. A DOS fiberoptic reflectance probe was used to collect white light spectra at two probing depths using two short fixed source-collector pairs with optical probing depths sensitive to the skin surface. The acquired spectra were fit to a diffusion theory model of light transport in tissue to extract optical biomarkers (hemoglobin concentration, oxygen saturation, scattering power and slope) from superficial skin layers of nude mice, which were subjected to erythema inducing doses of ionizing radiation. A statistically significant increase in oxygenated hemoglobin (p < 0.0016) was found in the skin post-irradiation - confirming previous reports. More interesting, we observed for the first time that the spectral scattering parameters, A (p = 0.026) and k (p = 0.011), were an indicator of erythema at day 6 and could potentially serve as an early detection optical biomarker of skin toxicity. Our data suggests that reflectance DOS may be employed to provide quantitative assessment of skin toxicities following curative doses of external beam radiation.
Highlights
Radiation therapy (RT) in medicine is the application of high doses of ionizing radiation as a means of treating and / or controlling malignant growths
The tabulated values were correlated with diffuse optical spectroscopy (DOS) measurements up to the time of peak skin toxicity
Inter observer variability is of concern for skin toxicity evaluation during external beam radiation therapy as non-standardized, anecdotal training between treatment units and inexperience from rotating trainees could result in missed diagnosis
Summary
Radiation therapy (RT) in medicine is the application of high doses of ionizing radiation as a means of treating and / or controlling malignant growths. Despite efforts to avoid toxicities to normal tissues, radiation induced skin reactions are a common side effect of treatment resulting in significant distress and discomfort to patients [1] Such acute effects include erythema and manifestations of moist desquamation and ulceration in more serious cases. While damage to the basal skin layer has typically been shown to occur at ~20-25 Gy (~10 fractions) [3], a variety of risk factors exist, which complicate the specific threshold dose and severity of toxicity from patient to patient [4]. These reactions tend to progress throughout treatment and can persist beyond completion of the treatment. Current scoring systems for radiation skin reactions (i.e. RISRAS or RTOG scoring) require a qualitative clinical manifestation of the skin toxicity and are often criticized for their subjectivity [5,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
