BREATH-HOLD TARGET LOCALIZATION WITH SIMULTANEOUS KILOVOLTAGE/MEGAVOLTAGE CONE-BEAM COMPUTED TOMOGRAPHY AND FAST RECONSTRUCTION
BREATH-HOLD TARGET LOCALIZATION WITH SIMULTANEOUS KILOVOLTAGE/MEGAVOLTAGE CONE-BEAM COMPUTED TOMOGRAPHY AND FAST RECONSTRUCTION
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DOI：
10.1016/j.ijrobp.2010.01.030
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发表时间：
2010-11-15
影响因子：
7
通讯作者：
Wenz, Frederik
中科院分区：
文献类型：
--
作者：
Blessing, Manuel;Stsepankou, Dzmitry;Wenz, Frederik
目的：小肺肿瘤的低分割大剂量放射治疗通常是基于立体定向。锥束计算机断层扫描和屏气技术为精确的颅外患者定位提供了无创性的基础。然而，60岁的S的锥束CT采集时间超出了患者的屏气能力，导致呼吸运动伪影。通过将兆伏(MV)和千伏(KV)光子源(垂直安装在直线加速器上)相结合，并将机架旋转加速到允许的极限，数据采集时间可减少到15s。方法和材料：使用Elekta Synergy 6-MV直线加速器，iViewGT为mV-，XVI为千伏成像设备，使用Catphan体模和拟人胸腔体模。两种来源的图像都进行了连续的图像采集，在15 S范围内通过了90度的角度间隔。重建使用了图形处理器单元上的滤波反投影。结果：Catphan体模(CTP528高分辨率模块)的分辨率为3线/厘米。空间精度在2~3 mm以内。胸腔体模中不同形状肿瘤的直径测量精度在1.6 mm以内。与180度千伏扫描相比，信噪比降低68%。获得MV帧所产生的剂量累积到82.5mGy.千伏的贡献为
Purpose: Hypofractionated high-dose radiotherapy for small lung tumors has typically been based on stereotaxy. Cone-beam computed tomography and breath-hold techniques have provided a noninvasive basis for precise cranial and extracranial patient positioning. The cone-beam computed tomography acquisition time of 60 s, however, is beyond the breath-hold capacity of patients, resulting in respiratory motion artifacts. By combining megavoltage (MV) and kilovoltage (kV) photon sources (mounted perpendicularly on the linear accelerator) and accelerating the gantry rotation to the allowed limit, the data acquisition time could be reduced to 15 s.Methods and Materials: An Elekta Synergy 6-MV linear accelerator, with iViewGT as the MV- and XVI as the kV-imaging device, was used with a Catphan phantom and an anthropomorphic thorax phantom. Both image sources performed continuous image acquisition, passing an angle interval of 90 within 15 s. For reconstruction, filtered back projection on a graphics processor unit was used. It reconstructed 100 projections acquired to a 512 x 512 x 512 volume within 6 s.Results: The resolution in the Catphan phantom (CTP528 high-resolution module) was 3 lines/cm. The spatial accuracy was within 2-3 mm. The diameters of different tumor shapes in the thorax phantom were determined within an accuracy of 1.6 mm. The signal-to-noise ratio was 68% less than that with a 180 degrees-kV scan. The dose generated to acquire the MV frames accumulated to 82.5 mGy, and the kV contribution was