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Radiotherapy
Radiotherapy is a technique using ionising radiation created
by a Linear Accelerator (linac). The energy of these rays is
significantly higher than the x-rays used in medical
imaging. Radiotherapy is predominantly used to treat
malignancy as either a curative or palliative measure. It is
often used to treat tumours a priori but is typically
used in combination with surgery and/or chemotherapy. If
used after surgery, it is considered “Adjuvant” and if used
before other treatments, “Neoadjuvant”.
Non malignant conditions have also been
treated including keloid scars, Peyronie’s disease,
dysthyroid eye disease, pigmented villonodular synovitis,
pterygium,heterotopic ossification and trigeminal neuralgia.
Radiotherapy is administered by Therapy
Radiographers directed by a Consultant Radiotherapist (who
is a specialist cancer doctor) in a hospital setting.
Adjuvant doses are typically 45 – 60 Gray administered in
fractions over several weeks. This is given after planning
the treatment often using Computed Tomography, followed by
“Simulation”.
There are three main types of
radiotherapy:
External Beam
Brachytherapy
Unsealed Source
Side effects in the short term include
damage to skin, oral, pharyngeal and bowel mucosa,
infertility and fatigue. Longer term adverse effects include
hair loss, fibrosis, dryness and even cancer.
Another type of radiotherapy administered
via the bloodstream is “Radioisotope Therapy”eg
131I for thyroid cancer, Yttrium-90 bound to
hormones for neuroendocrine tumours and
Metaiodobenzylguanidine (MIBG) for neuroblastomas.
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