Zhou S M, Bentel G C, Lee C G, Anscher M S
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Int J Radiat Oncol Biol Phys. 1998 Aug 1;42(1):73-8. doi: 10.1016/s0360-3016(98)00190-4.
To compare the gross target volumes (GTVs) (prostate and seminal vesicles) defined on noncontrast and contrast-enhanced computed tomography (CT) images used for three-dimensional conformal treatment planning (3DCRT).
From 1993 to 1996, 39 patients referred for radiation therapy for adenocarcinoma of the prostate underwent pretreatment pelvic CT scanning with and without intravenous (i.v.) contrast for treatment planning purposes. Seven patients were excluded because of incomplete data sets. The prostate and seminal vesicles were outlined by the same physician on all images of 32 patients. On 18 CT exams, the prostate and seminal vesicles were blindly outlined a second time by the same physician to evaluate intraphysician consistency. Discrepancies between the GTVs outlined with and without contrast and between the first and second outline on the same study were assessed by calculating the projected area in the anterior-to-posterior (AP) and right lateral (RLAT) beam's-eye view (BEV). To assess the magnitude, frequency, and direction of discrepancies between the two GTVs, the extension of the GTVs in six directions (right, left, anterior, posterior, cephalad, and caudal) was determined.
The GTV outlined with contrast was larger in all directions, except caudal, in the majority of patients. The change in the GTV with contrast was significant in the cephalad (p=0.0003) and right (p=0.0007) directions, but not in the other directions. Although the increase with contrast in any direction was usually small (average < or =5 mm), these changes resulted in a significant increase in GTV area in both the AP and RLAT BEV (9.0%, p=0.0017 and 8.2%, p=0.023, respectively). The intraphysician variability in outlining the prostate/ seminal vesicles was minimal.
The addition of i.v. contrast does appear to make a significant difference in how the prostate and seminal vesicles are outlined by an experienced observer. The increase in area of the target, found when contrast is used, should be taken into consideration when designing the treatment fields for patients with carcinoma of the prostate.
比较用于三维适形治疗计划（3DCRT）的非增强和增强计算机断层扫描（CT）图像上定义的大体靶区（GTV）（前列腺和精囊）。
1993年至1996年，39例因前列腺腺癌接受放射治疗的患者为进行治疗计划而接受了盆腔CT扫描，扫描时静脉注射（i.v.）造影剂和未注射造影剂。7例患者因数据集不完整被排除。同一位医生在32例患者的所有图像上勾勒出前列腺和精囊。在18次CT检查中，同一位医生再次盲目勾勒出前列腺和精囊，以评估医生内部的一致性。通过计算前后（AP）和右侧（RLAT）射野视角（BEV）中的投影面积，评估有无造影剂时勾勒出的GTV之间以及同一研究中第一次和第二次勾勒之间的差异。为了评估两个GTV之间差异的大小、频率和方向，确定了GTV在六个方向（右、左、前、后、头侧和尾侧）的延伸范围。
在大多数患者中，除尾侧外，增强扫描勾勒出的GTV在各个方向上都更大。GTV在头侧（p=0.0003）和右侧（p=0.0007）方向上因增强扫描而发生的变化具有显著性，但在其他方向上没有。尽管在任何方向上增强扫描带来的增加通常都很小（平均≤5毫米），但这些变化导致AP和RLAT BEV中的GTV面积显著增加（分别为9.0%，p=0.0017和8.2%，p=0.023）。医生在勾勒前列腺/精囊时的内部变异性最小。
静脉注射造影剂似乎确实对经验丰富的观察者勾勒前列腺和精囊的方式产生了显著影响。在为前列腺癌患者设计治疗野时，应考虑使用造影剂时靶区面积的增加。
