目的 研究乳腺癌术后放疗血清心肌钙蛋白T（cTnT）的变化，探讨其与心脏损伤的关系。方法 将50例左乳腺癌术后放疗患者分为L组，50例右乳腺癌术后放疗患者分为R组，另将50例胸部以外部位放疗患者作为对照组。采用胶体金法分别测定所有患者放疗前、放疗进行中期、放疗结束时、放疗后3个月、放疗后6个月以及放疗后12个月的cTnT含量，cTnT＞0.03 ng/mL为诊断心肌损伤的界限值。结果 L组和R组放疗后血清cTnT阳性率与对照组相比差异均有统计学意义（P<0.05），而L组与R组相比差异无统计学意义（P>0.05）。L组和R组放疗结束时与放疗前比较，血清cTnT含量显著升高并达到峰值，差异有统计学意义（P<0.01）；放疗后6个月血清cTnT含量恢复正常。结论 乳腺癌术后放疗可引起血清cTnT显著升高，导致心脏损伤发生率明显增加；cTnT的变化可早期反映放射性心脏损伤，有利于尽早预防和治疗放疗并发症和后遗症。

Objective To explore variations of the serum cardiac troponin T (cTNT) level for patients who underwent radiotherapy after mastectomy and to investigate the relationship between cTNT and myocardial damage. Methods Patients undergoing radiotherapy after mastectomy were selected and divided into the L group (50 patients underwent left mastectomy) and R group (50 patients underwent right mastectomy). The control group included 50 patients underwent radiotherapy at locations other than the thorax. The cTnT level of all patients was detected by the colloidal gold method before, in the middle of, and at the end of radiotherapy, 3 months, 6 months, and 12 months after radiotherapy, respectively. cTnT＞0.03 ng/mL was the criterion for the diagnosis of myocardial damage. Results Positive rates of the serum cTNT level of the group L and group R after radiotherapy were significantly different to that of the control group (P<0.05), while the difference of the L group and R group was not statistically significant (P>0.05). Compared to the serum cTNT level of the L group and R group detected before radiotherapy, the serum cTNT level detected at the end of radiotherapy increased significantly and reached the peak value. The differences were statistically significant (P<0.01). The serum cTNT level was back to normal 6 months after radiotherapy. Conclusion Postmastectomy radiotherapy (PMRT) may lead to the significant rise of serum cTNT level and increase the incidence of myocardial damage. Variations of the cTNT level can predict radioactive myocardial damage at early stage and is helpful for the early prevention and treatment of complications and sequelae relevant to the radiotherapy.