You are not radioactive and it is not harmful to anyone around you unless you have an implant of
radioactive seeds, wire or ingested/infused radiopharmaceuticals.
It is not unusual to feel tired during the time you are receiving radiation therapy. Many patients find it
helpful to take an afternoon nap or get more sleep each night. Usually, you can continue your normal
lifestyle. Your body is your best guide.
Treatment Modalities
Photon Beam Therapy
Photons are x-rays produced with a machine like the linear
accelerator or gamma rays from a Cobalt-60 unit. These high
energy photons are capable of penetrating deeply into tissues to
reach deep seated tumours while actually delivering less
radiation dose to superficial tissues such as the skin. The actual
photon energy chosen to treat a tumour depends on the
characteristics of the tumour, patient and treatment technique.
The linear accelerator is capable of rotating around a patient
lying on a treatment couch, treating the tumour from several
angles More often, two or more intersecting beams of radiation
are directed at a tumour from different directions.
Electron Beam Therapy
Most patients are treated with x-ray beams produced by linear accelerators. These accelerators can also
produce a beam of high-energy electrons which penetrate into tissue to a much more limited depth than
x-rays. The treatment effect of electrons and x-rays is considered identical. Electron beams can be used
for treating superficial tissues such as skin, lymph nodes and whenever it is preferable to deliver a higher
radiation dose superficially and relatively less dose to deeper tissues.
Conformal Three Dimensional Radiotherapy
The objective of radiation therapy is to deliver a high dose to the tumour to achieve a high level of local
control while keeping the dose to neighboring healthy tissues as low as
possible.
In conventional radiation therapy, the dose distribution can only be
evaluated in a single, usually transverse, central plan although the
tumour and the neighboring tissues bear complex three-dimensional
relationships to one another. To ensure that the tumour receives an
adequate dose, a margin is included around the tumour volume to
account for the uncertainties in tumour delineation and dosimetry and
deviations due to patient movement. This safety margin often limits the
delivery of a high dose to the target volume because of the tolerance of
the normal tissues included in the irradiation.
Three dimensional (3D) conformal radiation therapy is a sophisticated irradiation technique which
allows a high dose delivered to the tumour while keeping the dose to the adjacent normal tissues below
tolerance. 3D conformal therapy combines modern imaging technology (such as CT and MRI) for
accurate tumour delineation with state-of-the-art computer planning systems for treatment planning and
the latest development in linear accelerator technology such as the multileaf collimators for precise and
sophisticated dose delivery.
High Dose Rate (HDR) Remote Afterloading Brachytherapy
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