暴露于低剂量 (LD) 电离辐射 (IR)，例如计算机断层扫描 (CT) 检查中使用的辐射，可能与癌症风险相关。然而，癌症的发展可能取决于个体的放射敏感性。在本研究中，我们评估了两种具有不同放射敏感性的淋巴母细胞系对 20 mGy CT 扫描辐射剂量的反应差异。研究了几个参数：基因表达、DNA 损伤及其修复，以及细胞生存力、增殖和死亡。与中剂量500 mGy后的结果进行比较。20 mGy IR后，放射敏感（RS）细胞系表现出DNA损伤增加，细胞增殖和凋亡更高，而放射抗性（RR）细胞系不敏感到这个LD。有趣的是，RR细胞系表现出较高的抗氧化基因表达，该基因可以被细胞用作保护机制。 500 mGy 剂量后，两种细胞系均受到 IR 的影响，但差异显着。 RS细胞表现出DNA损伤和细胞凋亡增加，但细胞增殖和细胞活力下降，以及抗氧化反应减弱。在具有不同放射敏感性的两种细胞系之间观察到了不同的生物学效应，这些差异在放射敏感性不同的细胞系之间观察到了不同的生物学效应，这些差异在放射敏感性不同的细胞系之间观察到了差异。 CT 扫描剂量。如果进一步的研究证实这一点，人们可能会认为，具有放射敏感性相关基因变异的个体可能更容易受到 IR 的长期影响，从而可能增加 LD 暴露后的癌症风险。

Exposure to low doses (LD) of ionizing radiation (IR), such as the ones employed in computed tomography (CT) examination, can be associated with cancer risk. However, cancer development could depend on individual radiosensitivity. In the present study, we evaluated the differences in the response to a CT-scan radiation dose of 20 mGy in two lymphoblastoid cell lines with different radiosensitivity.Several parameters were studied: gene expression, DNA damage, and its repair, as well as cell viability, proliferation, and death. Results were compared with those after a medium dose of 500 mGy.After 20 mGy of IR, the radiosensitive (RS) cell line showed an increase in DNA damage, and higher cell proliferation and apoptosis, whereas the radioresistant (RR) cell line was insensitive to this LD. Interestingly, the RR cell line showed a higher expression of an antioxidant gene, which could be used by the cells as a protective mechanism. After a dose of 500 mGy, both cell lines were affected by IR but with significant differences. The RS cells presented an increase in DNA damage and apoptosis, but a decrease in cell proliferation and cell viability, as well as less antioxidant response.A differential biological effect was observed between two cell lines with different radiosensitivity, and these differences are especially interesting after a CT scan dose. If this is confirmed by further studies, one could think that individuals with radiosensitivity-related genetic variants may be more vulnerable to long-term effects of IR, potentially increasing cancer risk after LD exposure.