Noninvasive assessment of cutaneous alterations in mice exposed to whole body gamma irradiation using optical imaging techniques

Feature-Based vs. Deep-Learning Fusion Methods for the In Vivo Detection of Radiation Dermatitis Using Optical Coherence Tomography, a Feasibility Study

Acute radiation dermatitis (ARD) is a common and distressing issue for cancer patients undergoing radiation therapy, leading to significant morbidity. Despite available treatments, ARD remains a distressing issue, necessitating further research to improve prevention and management strategies. Moreover, the lack of biomarkers for early quantitative assessment of ARD impedes progress in this area. This study aims to investigate the detection of ARD using intensity-based and novel features of Optical Coherence Tomography (OCT) images, combined with machine learning. Imaging sessions were conducted twice weekly on twenty-two patients at six neck locations throughout their radiation treatment, with ARD severity graded by an expert oncologist. We compared a traditional feature-based machine learning technique with a deep learning late-fusion approach to classify normal skin vs. ARD using a dataset of 1487 images. The dataset analysis demonstrates that the deep learning approach outperformed traditional machine learning, achieving an accuracy of 88%. These findings offer a promising foundation for future research aimed at developing a quantitative assessment tool to enhance the management of ARD.

Radiation-induced alterations in multi-layered, in-vitro skin models detected by optical coherence tomography and histological methods

BACKGROUND

Inflammatory skin reactions and skin alterations are still a potential side effect in radiation therapy (RT), which also need attention for patients' health care.

METHOD

In a pre-clinical study we consider alterations in irradiated in-vitro skin models of epidermal and dermal layers. Typical dose regimes in radiation therapy are applied for irradiation. For non-invasive imaging and characterization optical coherence tomography (OCT) is used. Histological staining method is additionally applied for comparison and discussion.

RESULTS

Structural features, such as keratinization, modifications in epidermal cell layer thickness and disorder in the layering-as indications for reactions to ionizing radiation and aging-could be observed by means of OCT and confirmed by histology. We were able to recognize known RT induced changes such as hyper-keratosis, acantholysis, and epidermal hyperplasia as well as disruption and/or demarcation of the dermo-epidermal junction.

CONCLUSION

The results may pave the way for OCT to be considered as a possible adjunctive tool to detect and monitor early skin inflammation and side effects of radiotherapy, thus supporting patient healthcare in the future.

Characterization of early-stage cutaneous radiation injury by using optical coherence tomography angiography

Cutaneous radiation injury (CRI) is a skin injury caused by exposure to high dose ionizing radiation (IR). Diagnosis and treatment of CRI is difficult due to its initial clinically latent period and the following inflammatory bursts. Early detection of CRI before clinical symptoms will be helpful for effective treatment, and various optical methods have been applied with limitations. Here we show that optical coherence tomography angiography (OCTA) could detect changes in the skin during the latent period in CRI mouse models non-invasively. CRI was induced on the mouse hindlimb with exposure to various IR doses and the injured skin regions were imaged longitudinally by OCTA until the onset of clinical symptoms. OCTA detected several changes in the skin including the skin thickening, the dilation of large blood vessels, and the irregularity in vessel boundaries. Some of OCTA findings were confirmed by histology. The study results showed that OCTA could be used for early CRI detection.

Comparison between reflectance confocal microscopy and 2-photon microscopy in early detection of cutaneous radiation injury in a mouse model in vivo

Cutaneous radiation injury (CRI) is a skin injury caused by high-dose exposure of ionizing radiation (IR). For proper treatment, early detection of CRI before clinical symptoms is important. Optical microscopic techniques such as reflectance confocal microscopy (RCM) and 2-photon microscopy (TPM) have been tested as the early diagnosis method by detecting cellular changes. In this study, RCM and TPM were compared in the detection of cellular changes caused by CRI in an in vivo mouse model. CRI was induced on the mouse hindlimb skin with various IR doses and the injured skin regions were imaged longitudinally by both modalities until the onset of clinical symptoms. Both RCM and TPM detected the changes of epidermal cells and sebaceous glands before clinical symptoms in different optical contrasts. RCM detected changes of cell morphology and scattering property based on light reflection. TPM detected detail changes of cellular structures based on autofluorescence of cells. Since both RCM and TPM were sensitive to the early stage CRI by using different contrasts, the optimal method for clinical CRI diagnosis could be either individual methods or their combination.