Lattanzi J, McNeeley S, Hanlon A, Schultheiss T E, Hanks G E
Department of Radiation Oncology, Community Medical Center, Toms River, New Jersey 08755-6423, USA.
Urology. 2000 Jan;55(1):73-8. doi: 10.1016/s0090-4295(99)00389-1.
Use of external beam radiation fields that conform to the shape of the target improves biochemical control in prostate cancer by facilitating dose escalation through increased sparing of normal tissue. By correcting potential organ motion and setup errors, ultrasound-directed stereotactic localization is a method that may improve the accuracy and effectiveness of current conformal technology. The purpose of this study was to quantify the precision of the transabdominal ultrasound-based approach using computed tomography (CT) as a standard.
Thirty-five consecutive men participated in a prospective comparison of daily CT and ultrasound-guided localization at Fox Chase Cancer Center. Daily CT prostate localization was completed before the delivery of each final boost field. In the CT simulation suite, transabdominal ultrasound-based stereotactic localization was also performed. The main outcome measure was a three-dimensional comparison of prostate position as determined by CT versus ultrasound.
Sixty-nine daily CT and ultrasound prostate position shifts were recorded for 35 patients. The magnitude of difference between the CT and ultrasound localization ranged from 0 to 7.0 mm in the anterior/posterior, 0 to 6.4 mm in the lateral, and 0 to 6.7 mm in the superior/inferior dimension. The corresponding directed average disagreements were extremely small: anterior/posterior, -0.09 +/- 2.8 mm SD; lateral, -0.16 +/- 2.4 mm SD; and superior/inferior, -0.03 +/- 2.3 mm SD). Analysis of the paired CT-ultrasound shifts revealed a high correlation between the two modalities in all three dimensions (anterior/ posterior r = 0.88; lateral r = 0.91; and superior/inferior r = 0.87).
Ultrasound-directed stereotactic localization is safe and as accurate as CT scanning in targeting the prostate for conformal external beam radiation therapy. The application of this technology to current conformal techniques will allow the reduction of treatment margins in all dimensions. This should diminish treatment-related morbidity and facilitate further dose escalation, resulting in improved cancer control.
使用与靶区形状相符的外照射野，通过增加对正常组织的保护来实现剂量递增，从而改善前列腺癌的生化控制。通过校正潜在的器官运动和摆位误差，超声引导立体定位是一种可提高当前适形技术准确性和有效性的方法。本研究的目的是以计算机断层扫描（CT）为标准，量化基于经腹超声方法的精度。
35名连续的男性患者参与了福克斯蔡斯癌症中心每日CT与超声引导定位的前瞻性比较。在每次最终推量野照射前完成每日CT前列腺定位。在CT模拟室中，也进行基于经腹超声的立体定位。主要观察指标是CT与超声确定的前列腺位置的三维比较。
记录了35例患者69次每日CT和超声前列腺位置的变化。CT与超声定位之间的差异幅度在前/后方向为0至7.0毫米，在侧方为0至6.4毫米，在上/下方向为0至6.7毫米。相应的定向平均差异极小：前/后方向，-0.09±2.8毫米标准差；侧方，-0.16±2.4毫米标准差；上/下方向，-0.03±2.3毫米标准差）。对配对的CT-超声变化分析显示，两种模式在所有三个维度上都有高度相关性（前/后方向r = 0.88；侧方r = 0.91；上/下方向r = 0.87）。
超声引导立体定位在适形外照射放疗中靶向前列腺时是安全的，且与CT扫描一样准确。将该技术应用于当前的适形技术将使所有维度的治疗边界得以缩小。这应能降低治疗相关的发病率，并有助于进一步增加剂量，从而改善癌症控制。
