Figure 1
From: Changes in volume of stage I non-small-cell lung cancer during stereotactic body radiotherapy
Method to evaluate tumor volume using an image analyzing system, Dr. View/LINAX. (A) First, the CT images were displayed at an optimal window level of -400 HU with a width of 1,400 HU. (B) The region above -250 HU was automatically extracted (gray areas). (C) The gray-painted structures outside the tumors such as vessels and chest walls (arrows) were manually excluded, and the tumor volume of the gray-painted regions was calculated.