Reduction of parotid damage by Continuous Hyperfractionated Accelerated Radiotherapy

用模型实验系统检测连续超分割加速放射治疗(CHART)对腮腺的损伤。用磁共振成像仪对腮腺进行磁化传递对比(MTC)成像，观察腮腺损伤情况。为评价大鼠腮腺的损伤程度，对大鼠腮腺进行5~30GyX射线照射。我们测量了受损腮腺来源的血和尿淀粉酶活性，以及剩余总淀粉酶通过时腮腺中的淀粉酶活性。至于用于检测MTC的脉冲序列，已经了解到梯度回波或FISP是有用的。尿淀粉酶活性最大值出现的时间因腮腺吸收剂量的不同而不同。提示腮腺腺泡细胞照射后出现细胞死亡的机制因剂量不同而不同。

The parotid damage with Continuous Hyperfractionated Accelerated Radiotherapy (CHART) was examined by the model experiment system. To detect the parotid damage, Magnetization Transfer Contrast (MTC) was made an image with MRI device. To evaluate the damage of the parotid gland, X rays were irradiated to the rat parotid gland with 5Gy to 30Gy. We measured the serum and the urine amylase activity of the damaged parotid origin, and in the parotid at the time of the remaining total amylase passing.As for pulse sequence used to detect MTC, it has been understood that gradient echo or FISP is useful. It was clarified to the maximum value appearance of the urine amylase activity that time was different by the difference of the absorbed dose of the parotid. It is suggested that the mechanism of the appearance of the cell death by the irradiation of the parotid acinar cell is different depending on the dose.