Physiological Imaging-Defined, Response-Driven Subvolumes of a Tumor

Journal Article · Mon Apr 01 04:00:00 EDT 2013 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2012.10.036· OSTI ID:22224436

Farjam, Reza ^[1]; Tsien, Christina I.; Feng, Felix Y. ^[2]; Gomez-Hassan, Diana ^[3]; Hayman, James A.; Lawrence, Theodore S. ^[2]; Cao, Yue ^[1]

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1. Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan (United States)
2. Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)
3. Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States)

Purpose: To develop an image analysis framework to delineate the physiological imaging-defined subvolumes of a tumor in relating to treatment response and outcome. Methods and Materials: Our proposed approach delineates the subvolumes of a tumor based on its heterogeneous distributions of physiological imaging parameters. The method assigns each voxel a probabilistic membership function belonging to the physiological parameter classes defined in a sample of tumors, and then calculates the related subvolumes in each tumor. We applied our approach to regional cerebral blood volume (rCBV) and Gd-DTPA transfer constant (K{sup trans}) images of patients who had brain metastases and were treated by whole-brain radiation therapy (WBRT). A total of 45 lesions were included in the analysis. Changes in the rCBV (or K{sup trans})–defined subvolumes of the tumors from pre-RT to 2 weeks after the start of WBRT (2W) were evaluated for differentiation of responsive, stable, and progressive tumors using the Mann-Whitney U test. Performance of the newly developed metrics for predicting tumor response to WBRT was evaluated by receiver operating characteristic (ROC) curve analysis. Results: The percentage decrease in the high-CBV-defined subvolumes of the tumors from pre-RT to 2W was significantly greater in the group of responsive tumors than in the group of stable and progressive tumors (P<.007). The change in the high-CBV-defined subvolumes of the tumors from pre-RT to 2W was a predictor for post-RT response significantly better than change in the gross tumor volume observed during the same time interval (P=.012), suggesting that the physiological change occurs before the volumetric change. Also, K{sup trans} did not add significant discriminatory information for assessing response with respect to rCBV. Conclusion: The physiological imaging-defined subvolumes of the tumors delineated by our method could be candidates for boost target, for which further development and evaluation is warranted.

• OSTI ID: 22224436
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 5 Vol. 85; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BLOOD
BRAIN
IMAGE PROCESSING
IMAGES
METASTASES
NEOPLASMS
PATIENTS
PROBABILISTIC ESTIMATION
RADIOTHERAPY