High atomic number (Z) element-based radiosensitizers have been widely reported for enhancing radiotherapeutic effect, while its limited tumor distribution and long-term safety are major limitations in clinics. In this study, we propose the clinically used lipiodol, a liquid radiological imaging agent with high iodine concentration, as a potential radiosensitizer. Compared to clinically approved high Z nanoradiosensitizer HfO, lipiodol emulsion shows much better tumor spatial distribution and tumor inhibiting ability at level upon radiation treatment. In addition to primary tumor, lipiodol emulsion also exhibited efficient targetability and inhibition of lymph node metastasis with radiation treatment. Furthermore, the mechanism study indicates that lipiodol enhances radiotherapeutic effect by generating extra reactive oxygen species to cause DNA damage and cell death, irrespective of cancer type. Lastly, toxicity assessments demonstrate the safety of lipiodol for practical medical applications. This report provides scientific evidence supporting the century-old lipiodol as an effective liquid radiosensitizer ready for clinical implementation.

中文翻译：

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临床上使用碘化油作为有效的放射增强剂

高原子序数（Z）元素放射增敏剂已被广泛报道用于增强放射治疗效果，但其有限的肿瘤分布和长期安全性是临床的主要限制。在本研究中，我们提出临床使用的碘油（一种高碘浓度的液体放射显像剂）作为潜在的放射增敏剂。与临床批准的高Z纳米放射增敏剂HfO相比，碘油乳剂在放射治疗后表现出更好的肿瘤空间分布和水平的肿瘤抑制能力。除了原发肿瘤外，碘油乳剂还表现出有效的靶向性和对放射治疗淋巴结转移的抑制作用。此外，机制研究表明，无论何种癌症类型，碘油都会产生额外的活性氧，导致 DNA 损伤和细胞死亡，从而增强放射治疗效果。最后，毒性评估证明了碘油在实际医疗应用中的安全性。该报告提供了科学证据，支持具有百年历史的碘油作为一种有效的液体放射增敏剂，可供临床使用。