Localization and protection of kidneys in radiation treatment planning using computed tomography.

Irradiation treatment portals of the upper abdomen must limit the dose to the kidneys. Sparing one-third of the parenchyma of each kidney will prevent late clinical sequelae. One hundred CT scans of the abdomen were studied to evaluate using the vertebrae as landmark for treatment planning. In lateral fields, using the anterior border of the vertebral column as a landmark for the posterior high isodose line will limit treatment to less than 60% (mean 22%) of a single kidney. Placing the edge of an anterior/posterior field 2 cm lateral to the vertebral column will limit the dose to less than 44% of a single kidney (mean 11%).