Volumetric-modulated arc therapy (VMAT)‎ versus 3D-conformal radiation therapy in supra-diaphragmatic Hodgkin’s Lymphoma with mediastinal involvement : a dosimetric comparison

الملخص EN

Purpose : To compare volumetric-modulated arc therapy (VMAT) with 3D-conformal radiation therapy (3D-CRT) mediastinal irradiation for stage I–II supra-diaphragmatic Hodgkin’s Lymphoma (HL).

Patients and methods : Eleven patients were planned for RT after 4–6 cycles of ABVD chemotherapy: conventional 3D-CRT (AP/PA) and VMAT plans were conformed to the same PTV.

Objective was to choose the best PTV coverage plan with the least OAR dose.

The 2 plans were compared for : PTV coverage, mean dose and V5,V20lung, mean dose and V30heart, V5, V10, V15breast (female patients), and the integral body dose.

Results: Both techniques achieved adequate PTV coverage.

Mean lung and heart dose was consistently lower in VMAT plans.

The lung V20 dose was acceptable for VMAT, but exceeded the tolerance threshold in 6 cases with 3DCRT plans.

A mean difference of 15.9 % for both lungs V20 favored VMAT plans; average MLD difference was 2.3 Gy less for VMAT plans.

Similarly, lower maximum and mean heart doses with a 3.3 Gy dose reduction and a 9.4% difference in V30 favored