The Prairie Lakes Cancer Center was the first Cancer Center in South Dakota to offer its patients a sophisticated radiation therapy called IMRT – Intensity Modulated Radiation Therapy. The goal at the Cancer Center is to continue to stay abreast of the latest oncology treatments and technology and bring advanced therapies – like IMRT – here to Watertown.
What is IMRT?
IMRT is a revolutionary type of treatment that has additional abilities to conform radiation to the size, shape and location of a tumor.
The goal of curative radiation cancer treatment is two-fold:
To deliver a lethal dose of radiation to the tumor; and
To spare nearby healthy structures such as normal tissues, nerves, spinal cord and organs.
IMRT represents a leap forward in curative radiation cancer treatment. The IMRT planning and delivery system is one of the most sophisticated technologies in the world.
Since IMRT was introduced in 1992, thousands of patients have been treated with IMRT technology.
Best candidates for IMRT
IMRT can be used to treat tumors anywhere in the body. Clinical evidence seems to show that people with prostate cancer, cancers of the head and neck, and cancers within the brain will benefit most from IMRT treatments. Your physician will discuss with you if IMRT is your best treatment option.
Other patients that benefit from IMRT include:
Patients with solid tumors of any size
Patients with multiple tumors such as metastatic lesions
Benefits of IMRT
IMRT may offer patients an increased chance for cure.
IMRT may reduce complications caused from radiation delivery.
IMRT can treat multiple tumors simultaneously.
IMRT can treat previously inoperable, odd–shaped tumors or tumors wrapped around or near healthy tissues or organs.
IMRT can treat recurrent cancers.
IMRT compared to conventional 3D radiation therapy
The effectiveness of conventional 3D radiation therapy is somewhat limited because radiation beams of uniform intensity are used. This approach can limit treatment options when tumors are not well separated from nearby organs. Because of this limitation, conventional 3D radiation can expose larger volumes of healthy tissue to radiation, which may cause complications. With IMRT, the dose of radiation that is delivered to the tumor can be more precisely shaped to the tumor and the dose to surrounding healthy tissue is minimized.
IMRT treatment technology
IMRT relies on two advanced technologies:
Inverse treatment planning — Through sophisticated formulations, this system determines the best treatment plan, maximizing dose to the tumor while minimizing exposure to surrounding healthy tissue.
Multileaf collimator (MLC) — This technology delivers the plan determined from the inverse treatment planning system. The MLC is composed of computer–controlled tungsten "leaves" or "shutters" that shift to form specific patterns, blocking the radiation beams according to the intensity profile from the treatment plan.
IMRT treatment procedure
The patient undergoes a treatment planning CT, MRI or PET study to determine location of the tumor(s).
When scanning takes place during the CT, MRI, or PET study, the
patient is immobilized so that the imaging is completed with the highest degree of accuracy.
A physician analyzes these images and determines the areas that need to be treated and areas that need to be spared (such as surrounding healthy tissues and organs).
Based on this analysis, a safe and effective IMRT treatment plan is developed.
After the plan is generated, the patient is immobilized and positioned on the treatment couch where patients receive treatment.
Radiation is then delivered to the patient via thousands of pencil –thin beams, which are targeted to the tumor with high accuracy.
Though treatment times vary from patient to patient, a single IMRT treatment should typically take only 15 to 30 minutes. An entire course therapy can vary from 10 to 40 treatments, depending on the type of cancer.
BAT works together with IMRT
BAT (B-mode acquisition and targeting system) is a state-of-the-art ultrasound–based tumor localization system that works in conjunction with IMRT to maximize the precision and effectiveness of the radiation dose to the tumor.
Safe and compatible
BAT is the first of its kind: a system that tracks tumor location and allows physicians to more precisely position the patient in alignment with the treatment plan. BAT offers the benefits of:
Increasing target accuracy — from 2cm to 2mm
Safely increasing radiation dosage
Working together with existing systems and processes
Providing safe, non–invasive imaging
Useful for any soft tissue structure
Originally developed to localize prostate tumors, BAT is considered a valuable tool for many kinds of radiation treatment, including cancers of the breast, bladder, liver, pancreas and neck.