Clinical Services - Image-guided Radiotherapy
Image-guided radiotherapy is the use of real-time imaging to improve the delivery of therapeutic radiation. IGRT is a strategy for treating malignancies that takes advantage of the technological advances in medical imaging made over the last few decades. With IGRT, radiation oncology clinicians possess tools that can better account for the uncertainties involved in setting up patients for fractionated radiation delivery. Additionally, IGRT allows for the monitoring of changes in tumor position due to the normal physiological motion of the body’s organs. With all this new information at their fingertips, physicians can now intervene and adapt treatment in ways that were not previously possible.
IGRT gives 3-dimensional “sight” to physicians, allowing them to better target tumors while minimizing the effect of radiation on surrounding organs. One of the best examples of IGRT in practice is its application to the treatment of early-stage prostate cancers. The normal physiological movement of organs near the prostate complicates the daily targeting of the gland for fractionated external beam radiation treatment. Radiation oncologists at the Comprehensive Cancer Center of Wake Forest University (CCCWFU) have been using the ACCULOC© IGRT prostate localization system since February of 2006. This system utilizes three small gold markers placed within the prostate gland during a minimally-invasive procedure as a surrogate target for the prostate. The markers can be imaged daily using X-rays and digital imaging devices called electronic portal imaging devices (EPIDs). Prior to daily radiation treatment, the treatment isocenter within the prostate is triangulated based on the positions of the gold markers using computer software. This technique allows for patients to be shifted such that the prostate is aligned to the isocenter for each treatment fraction. Since the precise location of the prostate is known, escalated doses of delivered radiation can be directed to the intended target using a conformal targeting method called intensity modulated radiotherapy (IMRT). Without ACCULOC©, the uncertainty of the prostate position would not allow physicians to use escalated radiation doses for fear of causing damage to healthy tissues and creating complications which may impact a patient’s quality of life.
As the advances of IGRT continue to be integrated into the radiation oncology clinic at CCCWFU, new technology will allow the potential benefits of this strategy to be applied to other clinical sites including head and neck cancers, paraspinal tumors, cervical cancers, and lung tumors. IGRT complements the efforts of WFUBMC clinicians and researchers in the area of Bioanatomic Imaging - an emerging treatment strategy which holds the promise of tailored delivery of therapeutic doses to targets using physiological and biological imaging information.