> Learn about Internal Radiation Therapy.
Intensity Modulated Radiation Therapy (IMRT)
What is IMRT?
IMRT is an advanced, precise method of external beam radiation therapy that delivers high doses of radiation
directly to the tumor while sparing surrounding healthy tissue. IMRT allows doctors to customize the radiation
dose by modulating, or varying, the amount of radiation given to different parts of the treatment area. This
modulation is done in highly accurate, three-dimensional detail, according to the shape, size and location of the tumor.
How does IMRT work?
First, doctors will create a detailed digital image of your body using a CT (computed tomography) scan, PET
(positron emission tomography) scan, or MRI (magnetic resonance imaging). This digital image will be loaded
onto a powerful computer and used to plan beam arrangements that will best target your tumor. This technology allows
your treatment team to focus higher doses of cancer-killing energy on tumors while preserving healthy tissue. Clinical
studies show that IMRT allows doctors to deliver high doses of radiation directly to the tumor, increasing
treatment success and reducing side effects.
When do you use IMRT?
IMRT is an excellent choice for cancer of the prostate, brain, gastrointestinal tract (esophagus, stomach, pancreas,
rectum and anus), and head and neck (nasopharynx, orapharynx, hypopharynx, larynx and oral cavity).
Image Guided Radiation Therapy (IGRT)
What is IGRT?
IGRT is when two and three-dimensional images are taken during a course of radiation treatment so the radiation therapy can
target the cancerous cells more accurately.
How does IGRT work?
When a patient undergoes radiation therapy for cancer treatment, the radiation oncologist must locate the tumor so the radiation
can be directed to the treatment area. Up to now, radiation oncologists had to deal with the tumor moving in and out of
range as the patient breaths by treating some healthy tissue around the tumor. The On-Board Imager, a robotic automated
system for Image-Guided Radiation Therapy, enables doctors to take X-ray images that pinpoint tumor sites and robotically
adjust the patient’s position automatically when necessary so as much healthy tissue as possible is spared. The entire
process takes about 20 minutes per patient making it a very practical solution for improving patient care.
When do you use IGRT?
St. Vincent’s Comprehensive Cancer Center was the first center in the country to treat lung cancer with robotic
image-guided stereotactic body radiation therapy, Respiratory Gating and the new On-Board Imager (OBI) technology.
You should speak with your doctor to see if this technology is right for you.
Respiratory Gating
What is respiratory gating?
Respiratory gating is the process of turning the radiation beam on and off based on your breathing cycle. Some
aggressive cancers such as lung tumors may require higher radiation doses for better control. Higher radiation
doses can only be delivered if the dose to normal tissues can be kept to safe levels. Respiratory gating can be
used in combination with stereotactic body radiosurgery or radiation therapy.
How does respiratory gating work?
When you breathe, your internal organs move by as much as several centimeters, causing cancer cells to move
in and out of the radiation treatment field. Computer-guided imaging, simulation and planning allow your physician
to pinpoint the tumor, establish treatment objectives and review many treatment options to determine the optimal
arrangement and dose of radiation beams. Using respiratory gating, your radiation treatment is synchronized to
your individual breathing pattern, targeting the tumor only when it is in the optimum range. This provides
the security of protecting healthy structures while targeting the tumor with significantly higher doses
of radiation. High doses of radiation ensure the best outcomes: greater control, tumor reduction, and potential
cure.
When do you use respiratory gating?
Respiratory gating is used to treat lung, liver, pancreatic and stomach cancers.
 |
 |
 |
| 1. 3-D planning targets
radiation beams to the contours of the tumor.
|
2. Respiratory Gating synchronizes
the radiation to the patient’s breathing.
|
3. Radiation is administered
directly to the tumor with pin-point accuracy. |
Stereotactic Radiosurgery (Radiation Therapy)
What is stereotactic radiosurgery?
Stereotactic radiosurgery, also called stereotactic radiation therapy, does not involve actual surgery.
The procedure uses a large dose of radiation to destroy tumor tissue. There are two types of stereotactic radiosurgery
- intracranial and extracranial.
Intracranial stereotactic radiosurgery
Intracranial stereotactic radiosurgery uses multiple beams of radiation to deliver large doses of radiation
to tumors in the brain. The patient's head is placed in a special frame, which is attached to his or her
skull. The frame is used to aim high-dose radiation beams directly at the tumor inside the patient's head.
The dose and area receiving the radiation are coordinated very precisely. Nearby normal brain tissues are not
damaged by this procedure. Treatment is performed as an outpatient with only one treatment that takes about
45 minutes.
Extracranial stereotactic radiosurgery
Extracranial stereotactic radiosurgery or stereotactic body radiosurgery uses multiple beams of radiation to
deliver large doses of radiation to cancerous cells in the body, such as tumors in the lungs, liver and
upper abdomen.
How does stereotactic body radiosurgery work?
First, you will receive a CT, MRI or PET scan, which your doctor will use to pinpoint the tumor, establish
treatment objectives and review many treatment options to determine the optimal arrangement and dose of the
radiation beams. Using respiratory gating, your radiation treatment is synchronized to your individual breathing
pattern, targeting the tumor only when it is in the optimum range. This provides the security of protecting
healthy structures while targeting the tumor with significantly higher doses of radiation. High doses of radiation ensure
the best outcomes: greater control, tumor reduction, and potential cure. This outpatient treatment consists
of five treatments given three times a week for two weeks.
CT-based Conformal Radiation Therapy
What is CT-based conformal radiation therapy?
CT-based conformal radiation therapy uses computerized tomography (CT) scans to create a three-dimentional
(3D) image of the body, which helps doctors better target the tumor and minimize damage to healthy tissue.
When do you use CT-based conformal radiation therapy?
CT-based conformal radiation therapy is used on all patients who undergo radiation therapy.
RapidArc Radiotherapy
What is RapidArc Radiotherapy?
RapidArc Radiotherapy is a technology that provides a new approach to image-guided, intensity-modulated radiation therapy
(IG-IMRT) that delivers precise treatments in shorter times than conventional IMRT.
How does RapidArc Radiotherapy work?
RapidArc rotates 360 degrees around the patient, enabling the very small beams with varying intensity to be aimed at the tumor from
multiple angles. Unlike helical IMRT treatments or other forms of radiation therapy, with RapidArc the radiation treatment being
delivered to the patient can be modulated continuously throughout treatment. This means that higher doses of radiation are delivered
to hit the tumor harder, and less radiation is delivered to surrounding healthy tissue.
When do you use RapidArc Radiotherapy?
You should speak with your doctor to see if this technology is right for you.
