CT Scanning
The first step of Tomotherapy treatment is to have a CT scan done. The patient is set-up on our PET/CT
scanner flat table top with immobilizing devices to ensure reproducibility and comfort. After the CT scan is done the origin of
the scan is tattooed on the skin. The tattoos are very tiny dot marks which assist in positioning the patient during the treatment
course on a daily basis.The images are then exported to our Varian Eclipse contouring workstation.
Contouring and Prescription
Contouring, simply stated is drawing the tumor volume and the surrounding normal structures on the CT images.
This is a very important task in achieving success in Radiation treatment. Contouring is done at our Varian-Eclipse contouring station.
The doctor then decides how much radiation the tumor
should receive, as well as acceptable levels for surrounding structures.
Our radiation oncologist may use PET or MRI images along with the CT images
to accurately identify the target to treat and normal structures to spare. Once
the contouring process is completed, the CT images along with the structures drawn is exported to the Tomotherapy planning
station for radiotherapy planning.
Radiotherapy Isodose Planning
Isodose planning is done at the TomoTherapy planning station in Physics
and dosimetry area. The CT images after contouring is
imported into the TomoTherapy planning station.Every plan is individualized and made for
the specific needs of every case.
The Day of Treatment
After checking in for a daily treatment, the patient will be taken to the TomoTherapy treatment room where our radiation therapist
will help them onto the TomoTherapy treatment table. The patient will most likely lie on their back, and our therapist may fit
them with a special immobilizing device to help them hold still during treatment.
First, the table will move the patient through the machine once for daily CT imaging. Based on these images, the therapist may
fine tune the patient’s position via small table adjustments. Then the couch will move the patient through the machine once
again, this time more slowly, as the Tomotherapy system delivers the daily treatment.
Continuous 360º Treatment Delivery
The TomoTherapy treatment system delivers intensity-modulated radiation therapy (IMRT) with a helical (spiral)
delivery pattern. Photon radiation is produced by a linear accelerator (or linac for short), which travels in multiple circles around
the patient and moves in unison with a device called a multi-leaf collimator, or MLC. Meanwhile, the couch is also moving—guiding
the patient slowly through the center of the ring. Each time the linac makes a loop around the patient it directs a unique, optimized
set of radiation beamlets at the tumor. Quite literally, the Tomo process runs rings around cancer!
What You Can Expect
The number of treatments varies by case. On the average, the full daily TomoTherapy procedure takes about
30 minutes from when the patient enters the treatment room until they leave. This includes about five minutes for the daily CT to
be performed and another five minutes for treatment to be delivered (“beam-on time”). The remaining time is used for
patient set-up and image registration for proper positioning. TomoTherapy treatments are completely painless. The experience is
similar to having a CT scan or an X-ray taken.
You may hear a clicking noise and the hum of the machine, both of which
are normal sounds that the machine makes. During the treatment, our Tomo
team will be monitoring the patient with CCTV cameras
and also be able to communicate with our audio systems.
