Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

CT Assessment of Response to Therapy: Tumor Volume Change Measurement, Truth Data & Error



Charles D. Fenimore, Michael McNitt-Gray, Luc Bidaut, Samuel G. Armato, Charles R. Meyer, Marios A. Gavrielides, Geoffrey McLennan, Nicholas Petrick, Binsheng Zhao, Anthony P. Reeves, Reinhard R. Beichel, Grace Kim


Rationale and Objectives: This manuscript describes issues and methods that are specific to the measurement of change in tumor volume as measured from CT images and how these would relate to the establishment of CT tumor volumetrics as a biomarker of patient response to therapy. The primary focus is on the measurement of lung tumors, but the approach should be generalizable to other anatomic regions. Methods and Materials: The first issues addressed are the various sources of bias and variance in the measurement of tumor volumes, which are discussed in the context of measurement variation and its impact on the early detection of response to therapy. Results and Resources: Research is ongoing that seeks to identify the magnitude of some of these sources of error, and several of these efforts are described herein. In addition, several resources for these investigations are being made available through the NIH funded Reference Image Database to Evaluate Response to therapy in cancer (RIDER) project, and these are described as well. Other measures derived from CT image data that might be predictive of patient response are described briefly, as well as the additional issues that each of these metrics may encounter in real life applications. Conclusions: The manuscript concludes with a brief discussion of moving from the assessment of measurement variation to the steps necessary to establish the efficacy of a metric as a biomarker for response.
Journal of Translational Oncology


lung cancer, tumor volumetrics, response to therapy, CT imaging, database


Fenimore, C. , McNitt-Gray, M. , Bidaut, L. , Armato, S. , Meyer, C. , Gavrielides, M. , McLennan, G. , Petrick, N. , Zhao, B. , Reeves, A. , Beichel, R. and Kim, G. (2009), CT Assessment of Response to Therapy: Tumor Volume Change Measurement, Truth Data & Error, Journal of Translational Oncology, [online], (Accessed July 20, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created December 9, 2009, Updated February 19, 2017