• Treatment Simulation- involves image acquisition using CT or PET/CT
• Treatment Planning- dosimetry
• Treatment Delivery

After a radiation oncologist defines the target(s) on images that have been acquired using CT, PET or MRI), medical dosimetrists and medical physicists use a treatment planning program to compose treatment plans. Radiation therapists are responsible for patient set up and treatment delivery,

The goal of 3D Conformal Radiation Treatment Planning (3D CRT) is to judiciously select treatment parameters “zap” the tumor and to minimize (or eliminate) the radiation dose to surrounding healthy tissues. This treatment planning trials continue until the desired dosimetry is obtained.

While in 3D CRT, the treatment planner estimates and adjusts doses until a desired beam arrangement is achieved, Intensity Modulated Radiation Therapy (IMRT) planning goes one step beyond. IMRT uses an inverse planning process (vs the forward planning process used in 3D CRT), where through millions of computational iterations the best treatment parameters are computed to meet pre-defined goals, i.e., treat tumor and spare surrounding normal tissue. After a methodical preparation, in Spring of 2003, The Harold Leever Regional Cancer Center implemented the first clinical MLC-based dynamic IMRT technique (over the static counterpart) in the state of Connecticut. We selected this mode of treatment delivery since a speedier treatment delivery, using dynamic IMRT, lends itself to patient comfort and offers better dosimetry when dynamic events, e.g., breathing, take place during treatment.

Due to its exquisite “dose carving” capability, IMRT is particularly beneficial in treating tumors that are not well separated from surrounding tissues, or where critical organs or structures are nearby. At The Harold Leever Regional Cancer Center, IMRT is commonly used in treatment planning and radiation of the cancers in brain, head and neck, prostate, esophagus, and certain tumors of the chest wall. In treatment of breast, due to the motion of the chest during breathing, a forward IMRT technique is used to ensure the daily precision and accuracy of treatment is preserved. After all, our experienced medical dosimetrists and medical physicists do not retire “common sense” even when cutting-edge technology such as dynamic IMRT is available to them!