Interstitial implantation, radiotherapy

Figure 5. Radiotherapy afterloading cell for interstitial implantation (ALC-X)...

Figure 8. Radiotherapy seed assemblies for interstitial implantation (Seeds)...

External beam radiotherapy (including three-dimensional radiotherapy, intensity modulated radiotherapy, and extracranial stereotactic radiotherapy) is the most common way radiation is used to eradicate solid tumors, often with combined chemotherapy. The key limitation of external beam radiotherapy is the tolerance of normal liver parenchyma to radiation, which is much less than the dose required to control the liver tumors. Direct implantation of radionuclides into the tumor (brachytherapy) using interstitial seeds... 

Finally, changes in the brain that occur during the course of therapy are not properly considered in this model. Irradiation can be safely administered when a BCNU-loaded polymer has been implanted in monkey brains, suggesting the feasibility of adjuvant radiotherapy. Flowever, irradiation also causes necrosis in the brain. The necrotic region has a lower perfusion rate and interstitial pressure than tumor tissue thus, the convective interstitial flow due to fluid leakage is expected to be smaller. Interstitial... 

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