Procedure
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. Hepatic and renal function tests should be performed; patients with irreversibly elevated serum bilirubin are excluded, and iodinated contrast use should be avoided or minimized in patients with renal insufficiency. Tumor marker levels are also evaluated. Hepatic artery technetium (99mTc) albumin aggregated (MAA) scan is performed to evaluate hepatopulmonary shunting (resulting from hepatopulmonary syndrome). Increased pulmonary shunt fraction (>20%) indicates an increased likelihood of the radioactive particles traveling to the lung during therapy, leading to the adverse side effect of radiation pneumonitis.
The initial angiographic evaluation includes abdominal aortogram, superior mesenteric and celiac arteriograms, and selective right and left hepatic arteriograms. These studies allow for documentation of the gastrointestinal vascular anatomy and flow characteristics. Extrahepatic vessels found on angiographic evaluation are often embolized in order to prevent nontarget deposition of microspheres, that can lead to gastrointestinal ulceration. Once the branch of the hepatic artery supplying the tumor is identified and the tip of the catheter is selectively placed within the artery, the 90Y microspheres are infused.
After treatment, Bremsstrahlung scanning is recommended within 24 hours after radioembolization to evaluate the distribution of the Y-90 microspheres. Weeks after treatment, computed tomography is performed to evaluate anatomic changes, and positron emission tomography is performed to evaluate changes in metabolic activity.
Read more about this topic: Selective Internal Radiation Therapy