Treatment planning in radiation oncology and impact on outcome of therapy.

Irradiation is effective treatment for many patients with cancer. It can completely eradicate the tumor in the irradiated volume or it provides palliative relief to patients with incurable cancer. The success of radiation therapy depends on the delivery of an adequate dose to the entire tumor volume with acceptable morbidity in the surrounding normal tissues. The goals are to achieve the highest probability of local and regional tumor control with the lowest achievable incidence of side effects and to prolong the life of the patient with the best possible quality of life. Although treatment planning is extremely helpful in determining the best form of therapy, the responsibility for critical judgment and execution rests with the radiation oncologist, who, to treat patients effectively, must have sufficient training to define the target volume and critical structures, to interpret treatment planning information and to guide the physicist or dosimetrist in achieving the best dose distribution; have sufficient knowledge to select the best possible combination of dose and fractionation for a given site and volume; be competent to judge the quality of the dose distribution and the technical feasibility and accuracy of proposed plan; and understand the capabilities and limitations of the staff and computer systems involved in the radiation treatment planning process. No computer software can correct the radiation oncologist's errors of clinical judgment, misunderstanding of physical concepts, or inadequate treatment delivery.