Radiation therapy, or radiotherapy, uses ionizing radiation produced by
a linear accelerator (linac) to destroy cancer cells and shrink tumors.
The radiation passes through the body and delivers dose to the affected
area while minimizing dose to the skin and tissue it passes through.
Although the radiation affects both cancer and normal cells, it has a greater
effect on the cancer cells, damaging their genetic material and making
impossible for these cells to continue to grow and divide. Treatment aimed
at a cure will give the highest possible dose of radiation to the cancer
area (within safe limits) to attempt to destroy all the cancer cells.
Sometimes smaller doses are used, where the aim is to reduce the size
of a tumor and/or relieve symptoms.
Most patients undergo radiation therapy once a day, five days per week,
over a period lasting up to nine weeks. The total time, beginning with
your first and ending with your last session, is called a course of treatment.
Some patients are prescribed hypofractionated radiation therapy, which
delivers higher doses of radiation in a more targeted fashion over fewer
treatments.
Radiation therapy is used to both cure disease and alleviate the symptoms
of cancer. There are also a number of non-malignant conditions that are
treated using radiation therapy.
What happens during Radiation Therapy
Here are the steps our team will take you through at Flagler Radiation
Oncology Center:
Consultation
The radiation oncologist may ask for diagnostic procedures to be undertaken,
either at Flagler Imaging Center or a similar facility. These can include
x-rays, computed tomography (CT), magnetic resonance imaging (MRI), positron
emission tomography (PET) scans, biopsies and blood tests. Once the nature
of the disease has been established, a treatment regime will be planned
and prescribed.
Imaging
MRI, CT or PET scanning, or ultrasound is required to determine the exact
size, shape and position of the area to be treated within the body, known
as the treatment site. These images are then used to plan the patients’
treatment. You are positioned exactly as you will be for your treatments,
which may involve the use of immobilization devices to help you keep still.
Marks are made on your skin to indicate the treatment area. Once you are
positioned, images are acquired to help your treatment team plan as precise
a treatment as possible while reducing the impact on organs and critical
structures.
Treatment Planning
Once your images have been taken your physician prescribes the appropriate
total dose of radiation and over how many days your treatment is to be
administered, considering the tumor target and critical structures in
the treatment area. Your physicist and dosimetrist work closely with your
radiation oncologist and use sophisticated software to calculate the position,
dose and frequency of the series of radiation beams that are to be your
treatment. Before treatment commences the treatment may be simulated –
i.e., performed in the treatment room, without radiation, to ensure the
correct treatment will be delivered later.
Delivery (treatment)
Treatment may be given on an out-patient or in-patient basis, dependent
on the patient’s health status. It is imperative that the prescription
and treatment plan is adhered to as any missed treatment may affect success.
The patient usually receives the same treatment each day for a course
of treatment, which can last up to nine weeks. Treatment is monitored
regularly and may be adjusted if the patient suffers from adverse side
effects or loses weight.
To receive the radiation therapy, you will lie on a couch under the machine,
and be asked to remain still during the actual treatment. Once all is
ready, your radiation therapist leaves the room to monitor your treatment.
The gantry of the linear accelerator begins to rotate around you, as you
breathe normally. You may see and hear this movement, but the treatment
is completely painless. Radiation cannot be seen or felt while it is being given.
During treatment a process of verification takes place. By using built-in
imaging on Versa HD, images are taken of the treatment site. These images
are used to verify both the patient position and the accuracy of the treatment beam.
Follow-up
Once your course of treatment is completed, you attend follow-up clinics
for up to five years, to monitor your disease and manage any post-treatment
side effects. Initially you will come to our center. Annual follow-ups
may then be conducted by the specialist who sent you to for treatment.
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