干口症是头颈部癌症放射治疗（RT）的常见副作用。然而，对于放疗后唾液腺实质和血管变化的时间动态的信息有限。为了填补这一知识空缺，我们在小鼠中进行了实验研究，采用超声（US）与核心gistered光声成像（PAI）来非侵入地评估放疗后唾液腺大小、结构、血管及氧合动力学的早期和晚期变化。放疗前后在免疫缺陷和免疫能力小鼠中进行了唾液分泌检测，同时进行离体组织检查和免疫组化验证。US显示唾液腺体积减少，并出现较早的放射后血管阻力增加。PAI显示唾液腺的氧气消耗减少。影像数据与唾液分泌和小叶泡损伤的组织学证据强相关。放射反应的强度和动力学受到宿主免疫状态的影响，免疫缺陷小鼠显示出较早和更明显的血管损伤和DNA损伤反应，而与之相比，免疫能力更好的动物则少受影响。我们的发现展示了非侵入式US-PAI监测放疗后唾液腺血液动力学动态变化的能力，并强调宿主免疫状态对唾液腺放疗损伤的影响。

Xerostomia is a common side effect of radiation therapy (RT) in patients with head and neck cancer. However, limited information is available on the temporal dynamics of parenchymal and vascular changes in salivary glands following RT. To address this gap in knowledge, we conducted experimental studies in mice employing ultrasound (US) with coregistered photoacoustic imaging (PAI) to noninvasively assess the early and late changes in salivary gland size, structure, vascularity, and oxygenation dynamics following RT. Multiparametric US-PAI of salivary glands was performed in immune-deficient and immune-competent mice before and after RT along with correlative sialometry and ex vivo histologic-immunohistochemical validation. US revealed reduction in gland volume and an early increase in vascular resistance postradiation. This was accompanied by a reduction in glandular oxygen consumption on PAI. Imaging data correlated strongly with salivary secretion and histologic evidence of acinar damage. The magnitude and kinetics of radiation response were impacted by host immune status, with immunodeficient mice showing early and more pronounced vascular injury and DNA damage response compared to immunocompetent animals. Our findings demonstrate the ability of noninvasive US-PAI to monitor dynamic changes in salivary gland hemodynamics following radiation and highlight the impact of the host immune status on salivary gland radiation injury.