Radiotherapy
Dosimetric evaluation of radiotherapy planning with internal biological target volume of non-small cell lung cancer based on PET-CT and 4DCT
Yingjie Zhang, Xia Xu, Jianbin Li, Jinghao Duan, Yili Duan, Chaoyue Hu, Aiping Zhang, Fengxiang Li, Wei Wang
Published 2019-04-25
Cite as Chin J Radiol Med Prot, 2019, 39(4): 274-279. DOI: 10.3760/cma.j.issn.0254-5098.2019.04.006
Abstract
ObjectiveTo compare the size of the internal target volume (ITV), biological target volume (BTV) and internal biological target volume (IBTV) based on PET-CT and 4DCT for primary non-small cell lung cancer (NSCLC), as well as try to apply IBTV in radiotherapy planning.
MethodsA total of 15 patients with NSCLC were sequentially scanned by an axial enhanced 3DCT, 4DCT and 18F-FDG PET-CT in the thoracic region. The gross target volumes (GTVs) of ten phases of 4DCT images were contoured, and ITV was obtained by fusion of ten GTVs. BTV based on PET-CT images was determined by the SUV 2.0. The IBTV was defined by fusion of ITV and BTV. Planning target volumes (PTVs) based on ITV, BTV, and IBTV (PITV, PBTV, PIBTV) were obtained by ITV, BTV and IBTV with a 10-mm expansion respectively. The metrics of PIBTV, PITV and PBTV were compared, and the planning parameters of target volumes and risk organs were evaluated.
ResultsThere was no significant difference between ITV and BTV, but there was significant difference between IBTV and ITV and BTV (F=22.533, P < 0.05). To include more than 95% volume of IBTV, it is necessary to expand the margin of 9.0(6.0, 12.0)mm based on BTV or 10.00(7.0, 12.0)mm based on ITV. There was no significant difference between the two groups (P > 0.05). Dice's similarity coefficient of BTV and ITV was 0.72(0.54, 0.79). The intensity modulated radiotherapy plan based on PBTV can guarantee 85.6%(80.5%, 91.2%)of PITV to reach the prescription dose, compared with 80.2%(74.4%, 87.6%)of PBTV by the plan from PITV. Additionally, the conformity index and homogeneity index were not ideal. The dosimetric parameters of PITV and PBTV in the PIBTV plan were much better than those in PBTV- and PITV plan.
ConclusionsThe radiotherapy plan based on PET-CT or 4DCT could not guarantee a reasonable dose distribution of PTV expanded from ITV or BTV. Thus, using IBTV for radiotherapy is advised.
Key words:
Non-small cell lung cancer; Intensity modulated radiotherapy; Internal biological target volume
Contributor Information
Yingjie Zhang
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Xia Xu
School of Qilu Medicine, Shandong University, Jinan 250012, China
Jianbin Li
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Jinghao Duan
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Yili Duan
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Chaoyue Hu
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Aiping Zhang
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Fengxiang Li
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
Wei Wang
Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China
