Treatment Planning

Several steps occur after simulation and prior to treatment; however, you do not need to be present during most of these steps.

The treatment planning computer is capable of extremely complex three-dimensional representation of the treatment area and surrounding normal tissues.

The radiation oncologist will define the area to be treated on the images obtained from the CT simulation. Often times the patient has had surgery and/or chemotherapy therefore the use the diagnostic studies such as CT, MRI and PET will be also be used to make sure the entire tumor volume is included.

Another factor the physician needs to consider is motion. A person’s breathing, the amount of urine in the bladder, etc. are all considered in the designation of the treatment area.

Defining the treatment area is important but so is defining the normal structures surrounding this area. Each tissue in the body had its own tolerance to radiation and knowledge of these doses is critical in designing a treatment plan.

The type of radiation used for treatment is also determined during the planning process. The treatment machine at Sanford Cancer Center has two photon energies and 5 electron energies, all with specific characteristics. The radiation oncologist and dosimetrist use this knowledge in the design of your treatment plan.

Using all of this information, the best possible plan for each individual will be developed. The radiation oncologist will determine the daily dose, the total dose and the number of treatments during the planning process.  The dosimetrist will determine what angles are needed from the machine and how much radiation from each of those angles are needed for each individual patient.

The complexity of the plan developed requires computer systems for treatment delivery. Transferring this data to these systems and implementing checks of these calculations from the treatment planning computer are done by a dosimetrist and physicist.

It may take several days after simulation for treatment planning to be completed.