Comparison of the Dose Distribution in the Two- and Four-Fields Treatment Plannings with Energy of 6 and 18 Mv in Patients with Hodgkin's Disease with Mediastinal Involvement

Hodgkin’s disease is a special type of lymphoma or cancer that is associated with the abnormal growth of cells in the lymphatic system. The purpose of this study was to investigate different methods of radiotherapy in women with Hodgkin’s disease who need radiotherapy. Due to the presence of sensitive organs in this area, and secondary disease and cancers after radiotherapy, the importance of reviewing various treatment plans, is outstanding.
The data of computed tomography (CT) scan for 18 women with Hodgkin’s disease with mediastinal involvement were used. In next step, contouring all sensitive organs inside the field and the involved volume was done, using treatment planning system of Seyedoshohada Hospital, Isfahan, Iran. Then, the comparisons between the anterior-posterior/posterior- anterior (AP/PA) common treatment with the energy of 6 and 18 Mv and the four-field techniques with different weights were performed.
Findings: The maximum dose reached to the breast was reduced to 33%, compared to the current parallel-opposite technique, in the four- filed technique. On the other hand, the four- filed technique caused an increase of about 2.8 times in the average dose, due to the side-fields. The mean dose reached to the treatment volume was 100-102 percent in the 2-field technique and 99.5 percent in the four-filed technique.
For women with Hodgkin’s disease with mediastinal involvement, using the two-field technique with 18 Mv photon weighing 1.5 of anterior and 0.5 of posterior, showed better results compared to the 6 photon. The use of the 4-field technique led to a decrease of V20 value for the whole lung and the average dose received by esophagus and aorta and spinal cord, and V30 value for the heart.