Rectilinear bone scanning: differentiation between metastases and degenerative spinal disease.

Criteria have been developed for radioisotope scanning of bone with an eight-colour-display rectilinear scanner, to differentiate metastases from degenerative spinal disease. If the area of increased uptake is two or more colours "hotter" than normal, this is probably due to metastases even if degenerative spinal disease coexists. The positivity of a scan due to degenerative spinal disease is a function of the degree of sclerosis adjacent to the intervertebral discs and apophyseal joints; it is not related to the degree of osteophyte formation.