Miceli Roberto, Ingrosso Gianluca, Ponti Elisabetta, di Cristino Daniela, Lancia Andrea, Bove Pier Luigi, Santoni Riccardo
Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
Pract Radiat Oncol. 2015 Nov-Dec;5(6):417-22. doi: 10.1016/j.prro.2015.07.006. Epub 2015 Aug 1.
To investigate intraprostatic gold coils positional stability analyzing intermarker distance in on-board cone beam computed tomography (CBCT) scans acquired throughout the entire treatment course.
A total of 29 fiducial markers (FMs) were implanted in 10 patients through the transperineal approach, under ultrasound guidance. After 2 weeks from the FM implantation, all the patients underwent CT and magnetic resonance imaging under radiation therapy-planning conditions. The planning CT was the reference CT (CTref) used to calculate the initial intermarker distances. For every patient, 8 CBCTi (i varying from 1 to 8) acquired once a week during the treatment course were selected to calculate intermarker distances and compared with CTref. Reconstructed images of CBCTi were exported to the treatment planning system, and every FM was contoured. A point of interest at the center of mass of each contoured FM was created. The mean coordinates obtained for point of interest at the center of mass of FMs were used to calculate relative marker distances on CTref and CBCTi.
No patient developed postimplantation complications. A total of 224 marker distance variations (MDVs) were calculated for all 29 markers. The average directional variation of all MDVs (± standard deviation [SD]) was -0.14 ± 0.86 mm. The average absolute variations of all MDVs (± SD) were 0.71 ± 0.51 mm. The largest observed variation was 1.9 mm. All patients had not significant temporal trends in their marker distances. The SD of the MDVs was computed for each set of markers in all 10 patients. The SDs ranged between 0.4 and 1.1 mm in individual patients. The average of the mean SDs was 0.6 mm.
The three-dimensional definition of each fiducial marker volume, using on-board CBCT, demonstrated the stability of FMs position throughout the entire radiation therapy treatment course.
通过分析在整个治疗过程中采集的机载锥形束计算机断层扫描（CBCT）图像中标记物间的距离，研究前列腺内金线圈的位置稳定性。
在超声引导下，通过经会阴途径为10例患者共植入29个基准标记物（FMs）。在植入FMs两周后，所有患者在放射治疗计划条件下接受CT和磁共振成像检查。计划CT作为参考CT（CTref）用于计算初始标记物间距离。对于每位患者，选择在治疗过程中每周采集一次的8幅CBCTi（i从1到8）来计算标记物间距离，并与CTref进行比较。将CBCTi的重建图像导出到治疗计划系统，并勾勒出每个FMs的轮廓。在每个勾勒出的FMs的质心处创建一个感兴趣点。利用FMs质心处感兴趣点获得的平均坐标来计算CTref和CBCTi上的相对标记物距离。
所有患者均未出现植入后并发症。对所有29个标记物共计算出224个标记物距离变化（MDVs）。所有MDVs的平均方向变化（±标准差[SD]）为-0.14±0.86 mm。所有MDVs的平均绝对变化（±SD）为0.71±0.51 mm。观察到的最大变化为1.9 mm。所有患者的标记物距离均无明显的时间趋势。计算了所有10例患者每组标记物的MDVs的SD。个体患者的SD范围在0.4至1.1 mm之间。平均SD的平均值为0.6 mm。
使用机载CBCT对每个基准标记物体积进行三维定义，证明了在整个放射治疗过程中FMs位置的稳定性。
