Planning Systems

          Clinical Planning: Same as the simulation equipment, the planning systems available are quite important to assure the highest quality in radiation treatments that are offered to patients. In most radiotherapy centers, a clinical planning is created. It consists in analyzing the actual situation and “by hand” to arithmetically calculate the treatment plan in order to have the best possible results with the minimum exposition of the patient to radiation. To aim this, only the area to be irradiated is focalized to proper intensity and depth of the beam; the intensity is assured to be equals in all the area of treatment. 

           2D PLANNING: In this case, rudimentary computing systems are used, where it is only possible to calculate in only 2 or 3 levels to the irradiating zone, taking as basis  the manual reconstructions of the body zone (contours), drawing in the inside the projection of the tumor to be treated. Through this computer system, sizes of the field and proper angles can be indicated; unfortunately its reproducibility is restricted.
           Although this system is better than the manual planning system, almost no radiation center possesses it.

           3D PLANNING: There are several versions of these planning systems and they’re usually very complex and allow the creation of a quite complete treatment plan (virtual). In this case the process starts with the contouring of aimed structures like the tumor volume and organs to protect in each of the tomographic slices performed in the simulator. This is a crucial task and it is comparable to the surgical procedure that the oncologist surgeon performs, the difference is that it is not necessary to have the physical presence of the patient. It is imperative in this process to include all the volume of the tumoral lesion, otherwise the part that be omitted won’t receive the dose of treatment, resulting in the eventual reactivation of the tumor. On the other hand, if healthy tissue or organs remain inside the treatment area, they will receive unnecessary radiation doses having as a result the death of vital tissue. In this case it is necessary to block properly those “in danger zones” (Conformal radiotherapy or 3D). The newest systems in the market allow us indicate modulated radiation in different zones with the same volume in order to treat zones that can be only from 1 to 5 mm one from the other and receive a difference in range intensity of 50%, reducing the most any undesired extra radiation.
            Unfortunately, in our country there are very few centers which may offer the 3D planning service.

 

Clinical Planning Example for an incipient larynx cancer. Clinical contouring.

Tridimensional planning example for an incipient larynx cancer.

Tridimensional planning example for an incipient larynx cancer. (Digital reconstruction x-ray)

 

2 D or Conventional planning for insipient larynx cancer.(Conventional x-ray).

Tridimensional planning for Bronco-genic cancer. (Volume contouring)

Tridimensional planning for Bronco-genic cancer. (Volume treatment definition)

Tridimensional planning for Bronco-genic cancer. (Treatment field definition and isodosis curves)

Tridimensional planning. Tridimensional reconstruction of a treatment field ( BEV: Beam Eye View). Implementation of multileaf collimator to protect healthy tissue is shown

Tridimensional planning. Dose volume histogram. Graphic representation of dose, receiving any given percent of an organ or volume of treatment.

Tridimensional planning example for Bronco-genic cancer (Organ contouring)

 

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