ABSTRACT
Erythema is a well-documented early indicator of tissue injury resulting from exposure to high doses of ionizing radiation. Close monitoring of radiation-induced injury to the skin can help identify opportunities for early interventions that may prevent or reduce more severe reactions. The gold standard for monitoring erythema is visual assessment (VA) by a trained clinician. This method has been criticized for being subjective and designed with very broad categorical descriptors.
This work introduces a newly developed VA scale called the clinician erythema assessment for radiation therapy (CEA-RT).The reliability and accuracy of the CEA-RT scale was tested among 20 radiation therapists who trained to use the scale on digital images of radiation induced erythema. CEA-RT demonstrated to be highly reliable when therapist’s grades were compared to themselves, but moderately accurate when therapist’s grades were compared to each. A follow-up study with real patients and fewer but more extensively trained raters was proposed to demonstrate the grading accuracy of the CEA-RT scale.
As an alternatively to VA, spectroscopy has the ability to monitor erythema by measuring the change in concentration of hemoglobin (Hb) within the vessels of the skin. These changes in Hb concentration are linked to the degree of erythema. This thesis also investigated the use of hyperspectral imaging (HSI) and diffuse reflectance spectroscopy (DRS) as potential technological alternatives for evaluating erythema.
In a second study, Erythema was artificially induced in 3 volunteers who participated in a pilot study designed to assess the ability of an experimental HSI camera to detect skin changes. The data extracted from the hyperspectral images was found to effectively yield spectral profiles and Dawson’s erythema indices (EI) in agreement with the erythema grades assigned by the gold standard therefore showing HSI to be a viable alternative of assessing erythema.
Finally, a third study compared DRS measurements to VA using the CEA-RT scale. The DRS system was previously used to measure in vivo erythema but did not compare spectral measurements to an accepted standard. Ten patient volunteers received daily DRS and VA evaluations for a period of 2 to 4 weeks. The results demonstrated that the Dawson’s EI calculated from the spectral data correlated well with the gold standard (VA grades) and that DRS is able to detect changes in the skin throughout the course of radiation treatments. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/24591 |
| Date | January 2019 |
| Creators | Doerwald-Munoz, Lilian |
| Contributors | Farrell, Thomas, Hayward, Joseph, Fang, Qiyin, Radiation Sciences (Medical Physics/Radiation Biology) |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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