Mujahid Alaa, Alotaibi Bashayr, DeMellier Chloe, Gallegos Carlos, Sherwani Mohammad, Alexandrian Ara, Sorace Anna, Brady Amy, George Remo
Nuclear Medicine and Molecular Imaging Sciences Program, Department of Clinical & Diagnostic Sciences, School of Health Professions, University of Alabama at Birmingham, Birmingham, AL.
Department of Radiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL.
Health Phys. 2025 Sep 1;129(3):204-213. doi: 10.1097/HP.0000000000001947. Epub 2025 Jan 16.
Ionizing radiation on the skin has the potential to cause various sequelae affecting quality of life and even leading to death due to multi-system failure. The development of radiation dermatitis is attributed to oxidative damage to the skin's basal layer and alterations in immune response, leading to inflammation. Past studies have shown that [ 18 F]F-2-fluoro-2-deoxyglucose positron emission tomography-computed tomography ([ 18 F]F-FDG PET/CT) can be used effectively for the detection of inflammatory activity, especially in conditions like hidradenitis suppurativa, psoriasis, and early atherosclerosis. Since currently there are no specific tests for radiation dermatitis, our study aimed to validate whether radiation dermatitis induced in mice can be accurately visualized and measured using [ 18 F]F-FDG PET/CT. We induced cutaneous radiation syndrome in BALB/c mice with different radiation absorbed doses and monitored symptom development through photography, PET imaging, and histopathology, marking the first attempt at non-invasively quantifying radiation dermatitis effects at the molecular level using PET imaging. Our results showed that there were progressive changes in the dorsal skin of irradiated mice, with notable differences between those exposed to varying doses of radiation. Erythema, epilation, and desquamation were more pronounced in mice exposed to lower doses (25 Gy and 35 Gy) than at 45 Gy; however, by the third week, severe skin deterioration, including ulceration and dermal atrophy, was evident in mice irradiated with 35 Gy and 45 Gy. PET/CT imaging revealed increased [ 18 F]F-FDG uptake in the irradiated dorsal skin area of all mice compared to controls, with more pronounced avidity for the lesion in the 25 Gy and 35 Gy than the 45 Gy. Comparison of tissue-normalized SUV Max values showed that both the 25 Gy and 35 Gy mice exhibited fourfold [ 18 F]F-FDG uptake in the dorsal skin compared to controls, while a twofold uptake was seen at 45 Gy, thus indicating substantial metabolic changes in the dorsal skin induced by radiation exposure. Histopathological analyses correlated with the above findings, demonstrating generalized hypertrophy and epidermal thickening in all irradiated mice compared to controls, with thicker epidermis observed with higher radiation doses and increased destruction of microvasculature. In conclusion, PET/CT emerges as a successful tool for imaging cutaneous radiation syndrome, with the observed dermal changes in irradiated mice closely aligning with metabolic alterations of the affected area.
皮肤受到电离辐射有可能引发各种后遗症，影响生活质量，甚至因多系统衰竭导致死亡。放射性皮炎的发生归因于皮肤基底层的氧化损伤以及免疫反应的改变，进而引发炎症。过去的研究表明，[18F]F - 2 - 氟 - 2 - 脱氧葡萄糖正电子发射断层扫描 - 计算机断层扫描（[18F]F - FDG PET/CT）可有效用于检测炎症活动，尤其是在化脓性汗腺炎、银屑病和早期动脉粥样硬化等病症中。由于目前尚无针对放射性皮炎的特异性检测方法，我们的研究旨在验证是否可以使用[18F]F - FDG PET/CT准确可视化并测量小鼠诱导产生的放射性皮炎。我们用不同的辐射吸收剂量在BALB/c小鼠中诱导皮肤辐射综合征，并通过摄影、PET成像和组织病理学监测症状发展，这标志着首次尝试使用PET成像在分子水平对放射性皮炎的影响进行非侵入性定量。我们的结果表明，受辐照小鼠背部皮肤出现渐进性变化，不同辐射剂量组之间存在显著差异。红斑、脱毛和脱屑在低剂量（25 Gy和35 Gy）照射的小鼠中比45 Gy照射的小鼠更明显；然而，到第三周时，35 Gy和45 Gy照射的小鼠出现了严重的皮肤恶化，包括溃疡和真皮萎缩。PET/CT成像显示，与对照组相比，所有小鼠受辐照的背部皮肤区域[18F]F - FDG摄取增加，25 Gy和35 Gy组的病变摄取比45 Gy组更明显。组织标准化SUV Max值的比较表明，25 Gy和35 Gy组小鼠背部皮肤的[18F]F - FDG摄取量是对照组的四倍，而45 Gy组为两倍，这表明辐射暴露在背部皮肤诱导了显著的代谢变化。组织病理学分析与上述发现相关，表明与对照组相比，所有受辐照小鼠均出现普遍的肥大和表皮增厚，辐射剂量越高表皮越厚，微血管破坏增加。总之，PET/CT成为成像皮肤辐射综合征的成功工具，在受辐照小鼠中观察到的皮肤变化与受影响区域的代谢改变密切相关。
