Woodford Katrina, Panettieri Vanessa, Ruben Jeremy D, Davis Sidney, Sim Esther, Tran Le Trieumy, Senthi Sashendra
Alfred Health Radiation Oncology, The Alfred, Melbourne, Victoria, Australia.
Department of Surgery, Central Clinical School, Monash University, Melbourne, Victoria, Australia.
Tech Innov Patient Support Radiat Oncol. 2019 Dec 16;12:16-22. doi: 10.1016/j.tipsro.2019.10.004. eCollection 2019 Dec.
SABR may facilitate treatment in a greater proportion of locally-advanced NSCLC patients, just as it has for early-stage disease. The oesophagus is one of the key dose-limiting organs and visualization during IGRT would better ensure toxicity is avoided. As the oesophagus is poorly seen on CBCT, we assessed the extent to which this is improved using two oral contrast agents.
MATERIALS & METHODS: Six patients receiving radiotherapy for Stage I-III NSCLC were assigned to receive 50 mL Gastrografin or 50 mL barium sulphate prior to simulation and pre-treatment CBCTs. Three additional patients who did not receive contrast were included as a control group. Oesophageal visibility was determined by assessing concordance between six experienced observers in contouring the organ. 36 datasets and 216 contours were analysed. A STAPLE contour was created and compared to each individual contour. Descriptive statistics were used and a Kappa statistic, Dice Coefficient and Hausdorff distance were calculated and compared using a t-test. Contrast-induced artefact was assessed by observer scoring.
Both contrast agents significantly improved the consistency of oesophagus localisation on CBCT across all comparison metrics compared to CBCTs without contrast. Barium performed significantly better than Gastrografin with improved kappa statistics (p = 0.007), dice coefficients (p < 0.001) and Hausdorff distances (p = 0.002), although at a cost of increased image artefact.
Barium produced lower delineation uncertainties but more image artefact, compared to Gastrografin and no contrast. It is feasible to use oral contrast as a tool in IGRT to help guide clinicians and therapists with online matching and monitoring of the oesophageal position.
立体定向消融放疗（SABR）可能有助于更大比例的局部晚期非小细胞肺癌（NSCLC）患者接受治疗，就像其对早期疾病的作用一样。食管是关键的剂量限制器官之一，在图像引导放射治疗（IGRT）期间进行可视化可以更好地确保避免毒性。由于在锥形束计算机断层扫描（CBCT）上食管显示不佳，我们评估了使用两种口服造影剂后这种情况的改善程度。
六名接受I - III期NSCLC放射治疗的患者在模拟和治疗前CBCT之前被分配接受50毫升泛影葡胺或50毫升硫酸钡。另外三名未接受造影剂的患者作为对照组。通过评估六名经验丰富的观察者在勾勒器官轮廓时的一致性来确定食管的可视性。分析了36个数据集和216个轮廓。创建了一个STAPLE轮廓并与每个个体轮廓进行比较。使用描述性统计，并计算卡帕统计量、骰子系数和豪斯多夫距离，并使用t检验进行比较。通过观察者评分评估造影剂诱导的伪影。
与未使用造影剂的CBCT相比，两种造影剂在所有比较指标上均显著提高了CBCT上食管定位的一致性。硫酸钡的表现明显优于泛影葡胺，卡帕统计量（p = 0.007）、骰子系数（p < 0.001）和豪斯多夫距离（p = 0.002）均有所改善，尽管代价是图像伪影增加。
与泛影葡胺和不使用造影剂相比，硫酸钡产生的轮廓描绘不确定性更低，但图像伪影更多。在IGRT中使用口服造影剂作为工具来帮助临床医生和治疗师在线匹配和监测食管位置是可行的。
