Multimodal Photoacoustic/Elastography Imaging for the Detection of Acute Radiation Dermatitis in Breast Radiation Therapy

Purpose: This study aimed to evaluate whether photoacoustic (PA), sound touch elastography (STE), and viscoelasticity (VE) can distinguish between normal and abnormal postradiation therapy breast skin and compare these methods with Radiation Therapy Oncology Group (RTOG) criteria at a 20 Gy threshold. Methods and Materials: Patients who met inclusion and exclusion criteria underwent PA, STE, and VE on the same day. Collected data included radiation dose, molecular type, RTOG, Fitzpatrick skin type, pathology, neoadjuvant chemotherapy status, TNM (tumor, node, metastasis) classification, surgical procedures, primary breast cancer location, body mass index, and age. A sample of 41 patients was determined using a 2-sample t test. Statistical tools such as t-tests, variance analysis, rank sum tests, and x(2) tests, along with random forest analysis and receiver operating characteristic curves, were used to evaluate the radiation dose effects. Results: Data from 66 patients showed significant differences in parameters such as dermis and subcutaneous tissue oxygen saturation, dermal thickness, and skin elasticity (P values < .05). However, minimum values of oxygen saturation and some photoacoustic measures were not significantly different. Notably, at a 20 Gy radiation threshold, significant variations in oxygen saturation, abnormal dermal thickness, and skin STE and VE were observed, proving more accurate than RTOG grading. Conclusions: Our findings demonstrate that PA and elastography imaging are effective in differentiating between normal and abnormal breast tissue and assessing radiation-induced changes, thereby highlighting the potential of these imaging techniques.