Three Dimensional Conformal Radiation Therapy (3D CRT)
Intensity Modulated Radiation Therapy (IMRT)
Image Guided Radiation Therapy (IGRT)
Three Dimensional Conformal Radiation Therapy (3D CRT)
3D conformal radiation therapy is a standard form of external beam radiation therapy, one of the cornerstones of modern radiation oncology.
Advances in imaging and computer technology allow radiation therapy to be delivered more safely and accurately. Simulation and treatment planning for radiation treatments used to be done with x-rays and required that the patient stay in place until all the planning was done. Now your doctor can do a computed tomography (CT) scan to find the correct position for treatment and to make marks for accurate daily set-up. Then you can go home and your doctor can spend more time designing your treatment plan. After your “virtual” plan is ready, you return and films are taken to ensure that your treatment will be delivered as planned.
Another advantage of 3D conformal radiation therapy is that it can allow radiation therapy to be delivered more safely. Sophisticated software allows your doctor to more accurately define where radiation therapy can treat and spare more normal tissue, resulting in less side effects.
Intensity Modulated Radiation Therapy (IMRT)
An advanced version of 3D conformal radiation therapy is called intensity modulated radiation therapy, or IMRT.
Similar to 3D conformal radiation therapy, IMRT is highly accurate at treatment delivery. Its further advantage is that IMRT can control the precision of the radiation dose delivery and allow it to drop off more rapidly than with 3D conformal radiation therapy.
In some diseases, such as prostate cancer, higher radiation doses with IMRT now allow better tumor control than was possible before. In carefully selected cases, this technology has allowed radiation oncologists to make a meaningful difference to improve the outcomes for patients.
Image Guided Radiation Therapy (IGRT)
With the higher precision of intensity modulated radiation therapy (IMRT), it has become increasingly important to consider any small movements that may take place. Each treatment (or fraction) is designed the same, but movement may occur in the target or normal tissue from day to day (interfraction) or during treatment (intrafraction).
Image-guided radiation therapy (IGRT) requires more frequent imaging to confirm through the course of treatment that your radiation treatments are being delivered accurately and safely.
Saints has recently become the first hospital in New England to treat patients with the Calypso 4D Localization System for IGRT. As a result, image-guided radiation therapy has made it possible to consider giving larger doses of external beam radiation to shorten the length of treatment for some diseases.
