IGRT and IMRT - Image Guided Radiotherapy and Intensity Modulated Radiation Therapy

IGRTposition, so s/he can add less of a margin. This in turn
Image Guided Radiotherapy (IGRT) is a treatmentmeans that less healthy tissue is irradiated / exposed
technique that takes into account tumour motion.to such a high dose.
Some tumours are not in a fixed position within theIMRT
body, meaning their exact location can change slightlyIntensity-Modulated Radiation Therapy (IMRT) is a
from day to day. IGRT involves determining thetype of radiotherapy that allows the clinical oncologist
position of the tumour everyday before giving anyto treat less healthy tissue. The linear accelerator
radiotherapy treatment and then altering the settingsmoves the MLC's while the radiotherapy treatment is
/ treatment positioning if the tumour has moved.taking place, allowing the radiation dose to be
In traditional radiotherapy planning the clinicalmodulated (conformed / controlled) very accurately
oncologist defines the tumour s/he wishes to treataround the tumour. IMRT also allows higher radiation
with the 3D data that was obtained during thedoses to be given, to the patient, with fewer side
planning CT scan. S/he then adds an area ( known aseffects caused.
a margin) around this to include any microscopic cellsThis technique is normally of most benefit for
that cannot be seen on the 3D data. A furtherpatients who are having their pelvis (prostate or
margin is then added to allow for movement of thegynaecological cancers) or head and neck treated.
tumour. IGRT allows the treatment radiographers toIMRT is not suitable for all treatment areas, but we
see if the tumour has moved and account for it inwould recommend you ask during your initial
the treatment process. The clinical oncologist canconsultation with the clinical oncologist whether it
then be confident the mobile tumour is in the correctwould be suitable for you.