What Is Tomotherapy?
Tomotherapy is the latest state-of-the art method of delivering Intensity modulated radiation beams directed precisely
to the tumor and saving normal healthy tissue surrounding the tumor. The accuracy and precision of the
treatment delivery process is unparalleled compared to conventional radiotherapy machines.
For accurate patient set-up and positioning, Tomo CT images play a critical role. With every treatment fraction,
we can see where the anatomy is, compared to where it’s supposed to be, and based on accurate, consistent 3D image pixel
locations relative to the treatment beam. Then, with automated image registration, we can quickly determine any required adjustment,
precisely apply the offsets and treat accurately.
The green area is the Tomo CT image and the gray area is the planning CT. With the automated image registration,
we can easily match to its accurate position.
Conventional radiation therapy machines deliver a wide beam of radiation from only a few angles. The Tomotherapy treatment system uses
its unique CT scanner design to deliver radiation continuously from all angles around the patient. And, it features patented
beam-modulating technology that divides a single beam into many smaller, narrow “beamlets.” More angles and more precise
modulation result in dose distributions that conform to tumors like never before. This, in turn, minimizes damage to surrounding
Along with integrated CT guidance, two fundamental differences enhance the precision of a Tomotherapy approach:
- A ring gantry design for helical delivery
- A superior binary multi-leaf collimator
for beam shaping and modulation
As the ring gantry rotates in simultaneous motion to the couch, helical fan-beam IMRT is continuously delivered from all angles
around the patient.The width of the fan-beam projected to the axis is 40 cm, and the maximum length the couch can transport
the patient is 160 cm.This means very large volumes can be treated in a single, simple set-up. In fact, it is possible to treat
a cylindrical volume 40 cm in diameter by 160 cm long. Even larger diameter volumes can be treated with a reduced number of beams.
Typically, tens of thousands of beamlets are included in a precisely-optimized Tomotherapy system treatment fraction.
A single beamlet corresponds to the radiation
emitted through an open leaf of the Tomo MLC with the gantry at any given angle, during any given rotation.
The Imaging Advantage
The Tomotherapy treatment system looks like a CT scanner because it is a CT scanner. It lets clinicians efficiently acquire 3D
CTimages of every patient, every day. With these images, clinicians can check the size, shape and location of tumors before each
treatment. Then they can compare that day’s image with the one used for planning, to make sure that radiation will be directed
to where it should be. Importantly, daily CT images can also be used to analyze and, if necessary, modify — a patient’s
treatment at any point during the treatment
course. Revolutionary, not evolutionary.
Conventional radiation therapy machines deliver a wide beam of radiation from only a few angles. The Tomotherapy treatment
system uses its unique CT scanner design to deliver radiation continuously from all angles around the patient. And, it features
Intensity modulating technology that divides a single beam into many smaller, narrow “beamlets.” More angles and more
precise modulation result in dose distributions that conform to tumors like never before. This, in turn, minimizes damage to
surrounding healthy tissue and minimizes
healthy tissue complications.
IMRT and Stereotactic Radiotherapy
All Tomotherapy treatments are IMRT treatments and some are precise stereotactic radiation therapy. The Tomotherapy system
offers fast and precise stereotactic radiation therapy, from planning to verification to delivery. Whether the case is simple or
complex, our CT-guided helical IMRT is always the natural choice. Our stereotactic radiation therapy allows us to achieve excellent
dose conformality—even with highly irregular targets—and rapid dose falloff outside each target volume. All on the same
plan. Treat multiple targets in a single delivery sequence with a single setup and no isocenter shifts. Our tools use actual patient
anatomy to localize the target at treatment time, reducing the
need for invasive frames and eliminating the need for specialized external targeting equipment.
Tomo Stereotactic treatments can be for Small brain lesions, Multiple metastases treated simultaneously, Gliomas adjacent to the brain stem, vertebral metastasis to spare the spine.
A new paradigm for stereotactic targeting and positioning
With Tomotherapy System, patient positioning occurs via 3D CT images as seen on planning scans and pre-treatment
mega-voltage CT scans. This means actual patient anatomy is used in place of a surrogate stereotactic coordinate system to localize
the target at treatment time. Furthermore, CT guidance allows soft-tissue, even the tumor itself, to be used in the process of
aligning the target according to the plan.
Can be used for single and multiple fraction intracranial treatments. With CT-based localization, the role of the immobilization
device is just to keep the patient still while on the treatment table. It does not act as the basis for a stereotactic coordinate
system – a task that traditionally requires invasive fixation for single fraction treatments. As well as improving patient
comfort, this means planning scans, treatment planning, and quality assurance can be performed over several days, for both single
and multiple fraction treatments.