Y-90 microsphere treatment requires patient-individualized planning with cross-sectional imaging and arteriograms. Contrast computed tomography and/or contrast-enhanced magnetic resonance imaging of the liver is required to assess tumor and normal liver volumes, portal vein status, and extrahepatic tumor burden. Liver and kidney function tests should be performed; patients with irreversibly elevated serum bilirubin, AST and ALT are excluded, as these are markers of poor liver function. The use of iodinated contrast should be avoided or minimized in patients with chronic kidney disease. Tumor marker levels are also evaluated. Hepatic artery technetium (99mTc) macro aggregated albumin (MAA) scan is performed to evaluate hepatopulmonary shunting (resulting from hepatopulmonary syndrome). Therapeutic radioactive particles travelling through such a shunt can result in a high absorbed radiation dose to the lungs, possibly resulting in radiation pneumonitis. A lung dose of >30 Gray indicates an increased likelihood of the adverse side effect of radiation pneumonitis. The initial angiographic evaluation can include an abdominal aortogram, Superior mesenteric and Celiac arteriograms, and<unk>  right and left hepatic arteriograms. These studies allow for documentation of the gastrointestinal vascular anatomy and flow characteristics. Extrahepatic vessels found on angiographic evaluation can be embolized in order to prevent nontarget deposition of microspheres, that can lead to gastrointestinal ulceration. Alternatively, the catheter tip can be moved more distally, past the extrahepatic vessels. Once the branch of the hepatic artery supplying the tumor is identified and the tip of the catheter is<unk> ly placed within the artery, the yttrium-90 or holmium-166 microspheres are infused. If preferred, the particle infusion can be alternated with contrast infusion, to check for stasis or backflow. The radiation dose absorbed is dependent on microsphere distribution within the tumor vascularization. Equal distribution is necessary to ensure tumor cells are not spared due to ~2.5mm mean tissue penetration, with maximum penetration up to 11mm for yttrium-90 or 8.7mm for holmium-166. After treatment, for yttrium-90 based microspheres, bremsstrahlung SPECT or PET scanning may be performed within 24 hours after radioembolization to evaluate the distribution. For holmium-166 based microspheres, quantitative SPECT or MRI imaging can be performed. Weeks after treatment, computed tomography or MRI can be performed to evaluate anatomic changes. Holmium-166 microspheres will still be visible on MRI after radioactivity has decayed due to its paramagnetic properties. Positron emission tomography may also be performed to evaluate changes in metabolic activity.
Selective internal radiation therapy
Stereotactic radiation therapy
Chemoradiotherapy
Image-guided radiation therapy
External beam radiotherapy
Tomotherapy
Radiation therapy
Nerve-sparing surgery