Three-dimensional (3D) conformal radiotherapy

Three-dimensional (3D) conformal radiotherapy is an accurate compilation of a treatment plan with computer support based on modern imaging diagnostic methods that allow for the most accurate (conformal) treatment of the target area with the most sparing effect on healthy adjacent tissues and organs within the risk region.

This is the initial type of irradiation on which more and more modern methods of irradiation are based. It gained distinction after using computer tomography it became possible to conduct a sufficiently accurate visualization diagnosis, which allows planning and carrying out irradiation from several directions.

To draw up a radiotherapy plan, a three-dimensional image of the patient is obtained on a computer tomograph. In this case, the patient's body is in the same position as with the radiotherapy itself. This is achieved through the use of special systems to control the placement and maintain the position of the body on both devices (CT and accelerator). With the aid of auxiliary devices, such as masks, the position of the patient on the table is fixed and can be reproduced at any time.

Based on this planned computed tomography and/or magnetic resonance imaging (MRI), the treating therapist determines on an individual basis at all CT levels for each patient the target amount of radiation and the organs in the risk zone and require maximum protection. This creates a three-dimensional image of the area on which radiation therapy will be performed.

At the final stage, the expert of medical physics using special software develops treatment plan taking into account the various maximum permissible doses of irradiation. Planning for conformal irradiation takes place in a “straight" direction”. In this case, taking into account the different directions of treatment of irradiation fields and associated stratifications, specialists try to calculate the optimal distribution of the radiation dose step by step. Each field of irradiation is limited by so-called collimators and, therefore, has individual boundaries. Ultimately, the goal of the treatment is to treat the entire tumor with the dose that is necessary to achieve the optimum effect, and how best to protect healthy tissues from negative effects.