A novel form of radiotherapy was unveiled at the Society of Nuclear Medicine's 57th Annual Meeting. This technique, known as radiomicrosphere therapy, involves the injection of tiny highly radioactive beads that "nestle up" with cancerous tumors and destroy them with precision.
"Radiomicrosphere therapy guided by molecular imaging is an emerging area of radiotherapy and has the potential to target treatments for cancer patients," said Ron Young, C.N.M.T., principal researcher and clinical manager of nuclear medicine at the Cleveland Clinic, Cleveland, Ohio. "This technique allows us to provide the most effective and individualized therapy with minimal complications for the patient." Radiomicrosphere therapy can cause damage to healthy tissues. Young emphasizes that technologists and physicians providing care must perform an imaging scan of patients to predict the destination of these particles and potentially destroy normal tissue. It’s believed that the best tool for determining the likely path of these cancer-killing microbeads, is the form of molecular imaging called SPECT/CT, which combines single photon emission computed tomography and X-ray computed tomography. With this form of radiotherapy, also called radioembolization, tiny beads are impregnated with a radioisotope and injected into the liver with a catheter inserted through the groin.
Technologists and nuclear medicine physicians simulate therapy by injecting patients with the imaging agent Tc99m-MAA, which emulates the migration pattern the spheres will take. Molecular and X-ray imaging with SPECT/CT technology provide the essential information interventional radiologists need to then block blood vessels surrounding the targeted organ with small metal coils, effectively isolating the microbeads during therapy. A study involved 99 patients who underwent conventional planar imaging with gamma camera technology followed by imaging with SPECT/CT prior to therapy. 23 patients out of the 99 who used SPECT/CT alone showed potential for complications. While only 9 patients showed potential for "shunting" or bleeding of the radioactive particles into other areas of the body, leading to the destruction of healthy tissues. Another patient's hepatic vein, the main blood vessel into the liver, was shown to be obstructed by the tumor, which informed the treating physician that therapy would need to be altered due to this obstruction. In this case, SPECT/CT was able to uncover a previously unknown complication that changed the course of treatment for the patient. SPECT/CT makes radiomicrosphere therapy a more powerful and safer tool for cancer therapy, according to the study.