Vascular and extravascular spaces in a transplantable rat tumour after local X-ray irradiation.

Local X-ray irradiation of a transplantable rat tumour in a single dose of 3000 R increased significantly the extracellular space of this tumor as estimated by the plasma-tissue equilibration of 51Cr-EDTA, while the plasma and red blood cell volume as estimated with 125I-labeled albumin and 59Fe-labelled erythrocytes after sacrifice by bleeding under ether anaesthesia were unchanged. These results combined signified a decreased cell volume of cells, excluding red blood cells.