Toya Ryo, Saito Tetsuo, Shimohigashi Yoshinobu, Yotsuji Yohei, Matsuyama Tomohiko, Watakabe Takahiro, Kai Yudai, Yamashita Yasuyuki, Oya Natsuo
Department of Radiation Oncology, Kumamoto University Hospital, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan.
Jpn J Radiol. 2018 Feb;36(2):159-163. doi: 10.1007/s11604-017-0698-8. Epub 2017 Oct 30.
We describe a treatment method with four-dimensional cone-beam computed tomography (4D-CBCT)-guided radiotherapy for gastric lymphoma.
We performed image-guided radiotherapy (IGRT) with 15 fractions for a gastric mucosa-associated lymphoid tissue lymphoma patient, using 4D-CBCT. The stomach was delineated based on 4D-CT images. For image guidance, an automatic registration between planning CT and 4D-CBCT images was performed based on the bony anatomy (bone matching), followed by manual registration based on the stomach in 4D-CBCT images of all 10 phases (4D matching). We calculated the covering ratio (CR) with variable stomach-to-planning target volume (PTV) margins, based on the images of all phases [CR (%) = the number of covering phases/all 150 phases × 100].
The patient underwent radiotherapy (RT) as scheduled, without any significant adverse effects. The appropriate PTV margins (CR ≥ 95%) were 25 mm (CR 99.3%) and 15 mm (CR 98.7%) for bone and 4D matching, respectively.
4D matching using 4D-CBCT is appropriate for IGRT of gastric lymphomas.
我们描述一种采用四维锥形束计算机断层扫描（4D-CBCT）引导的放射治疗胃淋巴瘤的方法。
我们对一名胃黏膜相关淋巴组织淋巴瘤患者使用4D-CBCT进行了15次分割的图像引导放射治疗（IGRT）。基于4D-CT图像勾勒出胃部轮廓。为了进行图像引导，首先基于骨骼解剖结构（骨匹配）在计划CT和4D-CBCT图像之间进行自动配准，然后在所有10个时相的4D-CBCT图像中基于胃部进行手动配准（4D匹配）。我们根据所有时相的图像计算了不同胃到计划靶体积（PTV）边界情况下的覆盖率（CR）[CR（%）=覆盖时相数/所有150个时相数×100]。
患者按计划接受了放射治疗（RT），未出现任何明显不良反应。对于骨匹配和4D匹配，合适的PTV边界（CR≥95%）分别为25 mm（CR 99.3%）和15 mm（CR 98.7%）。
使用4D-CBCT进行4D匹配适用于胃淋巴瘤的IGRT。
