Historically, radiation therapy planning had been done using two-dimensional imaging techniques. The limitation of this method was that it did not allow for full visualisation of the tissues and organs in and around the area for treatment.
3D conformal radiation therapy is a complex process that begins with a CT scan and the creation of individualised, 3D digital data sets of patient tumours and normal adjacent anatomy. These data sets are then used to generate 3D computer images and to develop complex plans to deliver highly conformed (focussed) radiation while sparing normal adjacent tissue.
Because higher doses of radiation can be delivered to cancer cells while significantly reducing the amount of radiation received by surrounding healthy tissues, the technique should increase the rate of tumour control while decreasing side effects.
The planning process is more complicated than a two-dimensional approach and so may take a little longer to prepare, but the decrease in side effects with 3D conformal radiation therapy is a major improvement in radiation therapy delivery.