用于螺旋断层放射治疗（TomoTherapy）剂量验证的剂量测定检查（Dosimetry Check™）的临床应用。

Clinical implementation of Dosimetry Check™ for TomoTherapy delivery quality assurance.

作者信息

Chung Eunah, Kwon Dongyeol, Park Taeyang, Kang Hyeri, Chung Yoonsun

机构信息

Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Department of Nuclear Engineering, Hanyang University, Seoul, Korea.

出版信息

J Appl Clin Med Phys. 2018 Nov;19(6):193-199. doi: 10.1002/acm2.12480. Epub 2018 Oct 24.

DOI:10.1002/acm2.12480

PMID:30354001

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6236814/

Abstract

PURPOSE

The delivery quality assurance (DQA) of intensity-modulated radiotherapy (IMRT) plans is a prerequisite for ensuring patient treatments. This work investigated the clinical usefulness of a new DQA system, Dosimetry Check™(DC), on TomoTherapy -based helical IMRT plans.

METHODS

The DQA was performed for 15 different TomoTherapy -based clinical treatment plans. In Tomotherapy machines, the couch position was set to a height of 400 mm and the treatment plans were delivered using QA-Treatment mode. For each treatment plan, the plan data and measured beam fluence were transferred to a DC-installed computer. Then, DC reconstructed the three-dimensional (3D) dose distribution to the CT images of the patient. The reconstructed dose distribution was compared with that of the original plan in terms of absolute dose, two-dimensional (2D) planes and 3D volume. The DQA results were compared with those performed by a conventional method using the cheese phantom with ion chamber and radiochromic film.

RESULTS

For 14 out of the 15 treatment plans, the absolute dose difference between the measurement and calculation was less than 3% and the gamma pass rate with the 3%/3 mm gamma evaluation criteria was greater than 95% for both DQA methods. The P-value calculated using Wilcoxon signed-rank test was 0.256, which implies no statistically significance in determining the absolute dose difference between the two methods. For one treatment plan generated using the 5.0 cm field width, the absolute dose difference was greater than 3% and the gamma pass rate was less than 95% with DC, while the DQA result with the cheese phantom method passed our TomoTherapy DQA tolerance.

CONCLUSION

We have clinically implemented DC for the DQA of TomoTherapy -based helical IMRT treatment plans. DC carried out the accurate DQA results as performed with the conventional cheese phantom method. This new DQA system provided more information in verifying the dose delivery to patients, while simplifying the DQA process.

摘要

目的

调强放射治疗（IMRT）计划的剂量验证（DQA）是确保患者治疗的前提条件。本研究探讨了一种新型DQA系统——剂量学检查（Dosimetry Check™，DC）在基于螺旋断层放疗（TomoTherapy）的IMRT计划中的临床实用性。

方法

对15个不同的基于TomoTherapy的临床治疗计划进行DQA。在TomoTherapy机器中，将治疗床位置设置为400 mm高度，并使用QA治疗模式执行治疗计划。对于每个治疗计划，将计划数据和测量的射束注量传输到安装了DC的计算机。然后，DC将三维（3D）剂量分布重建到患者的CT图像上。在绝对剂量、二维（2D）平面和3D体积方面，将重建的剂量分布与原始计划的剂量分布进行比较。将DQA结果与使用带有电离室和放射变色胶片的奶酪模体的传统方法进行的结果相比较。

结果

在15个治疗计划中的14个中，两种DQA方法的测量值与计算值之间的绝对剂量差异均小于3%，并且采用3%/3 mm伽马评估标准时伽马通过率均大于95%。使用Wilcoxon符号秩检验计算的P值为0.256，这意味着在确定两种方法之间的绝对剂量差异时无统计学意义。对于一个使用5.0 cm射野宽度生成的治疗计划，DC的绝对剂量差异大于3%，伽马通过率小于95%，而奶酪模体法的DQA结果通过了我们的TomoTherapy DQA公差。