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Determination of internal target volume for radiation treatment planning of esophageal cancer by using 4-dimensional computed tomography (4DCT). Int J Radiat Oncol Biol Phys 2014 Sep 01;90(1):102-9

Date

07/13/2014

Pubmed ID

25015201

DOI

10.1016/j.ijrobp.2014.05.015

Scopus ID

2-s2.0-84905916675   8 Citations

Abstract

PURPOSE: To determine an efficient strategy for the generation of the internal target volume (ITV) for radiation treatment planning for esophageal cancer using 4-dimensional computed tomography (4DCT).

METHODS AND MATERIALS: 4DCT sets acquired for 20 patients with esophageal carcinoma were analyzed. Each of the 4DCT sets was binned into 10 respiratory phases. For each patient, the gross tumor volume (GTV) was delineated on the 4DCT set at each phase. Various strategies to derive ITV were explored, including the volume from the maximum intensity projection (MIP; ITV_MIP), unions of the GTVs from selected multiple phases ITV2 (0% and 50% phases), ITV3 (ITV2 plus 80%), and ITV4 (ITV3 plus 60%), as well as the volumes expanded from ITV2 and ITV3 with a uniform margin. These ITVs were compared to ITV10 (the union of the GTVs for all 10 phases) and the differences were measured with the overlap ratio (OR) and relative volume ratio (RVR) relative to ITV10 (ITVx/ITV10).

RESULTS: For all patients studied, the average GTV from a single phase was 84.9% of ITV10. The average ORs were 91.2%, 91.3%, 94.5%, and 96.4% for ITV_MIP, ITV2, ITV3, and ITV4, respectively. Low ORs were associated with irregular breathing patterns. ITV3s plus 1 mm uniform margins (ITV3+1) led to an average OR of 98.1% and an average RVR of 106.4%.

CONCLUSIONS: The ITV generated directly from MIP underestimates the range of the respiration motion for esophageal cancer. The ITV generated from 3 phases (ITV3) may be used for regular breathers, whereas the ITV generated from 4 phases (ITV4) or ITV3 plus a 1-mm uniform margin may be applied for irregular breathers.

Author List

Chen X, Lu H, Tai A, Johnstone C, Gore E, Li XA

Authors

Xiaojian Chen PhD Assistant Professor in the Radiation Oncology department at Medical College of Wisconsin
Elizabeth M. Gore MD Professor in the Radiation Oncology department at Medical College of Wisconsin
Candice A. Johnstone MD, MPH Associate Professor in the Radiation Oncology department at Medical College of Wisconsin
X Allen Li PhD Professor in the Radiation Oncology department at Medical College of Wisconsin
An Tai PhD Associate Professor in the Radiation Oncology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Aged
Aged, 80 and over
Esophageal Neoplasms
Female
Four-Dimensional Computed Tomography
Humans
Male
Middle Aged
Movement
Odds Ratio
Radiotherapy Planning, Computer-Assisted
Respiration
Retrospective Studies
Tumor Burden
jenkins-FCD Prod-480 9a4deaf152b0b06dd18151814fff2e18f6c05280