Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Biophysics

Patient-specific verification of intensity-modulated radiation therapy (IMRT) plans can be done by the evaluation of the agreement between measured and calculated doses. This plays an essential role in the quality assurance (QA) procedures of intensity- modulated radiation therapy (IMRT) for head and neck tumors. In this work the absorbed dose is measured using ionization chamber (0.6 cm3 Farmer type), PTW 2D-array 729 and GafChromic film EBT2 in order to verify the IMRT procedures. The ionization chamber is used for point dose measurements. The 2D-array and GafChromic films are used for 2D graphical dose distribution. Four different gamma criteria of dose difference (DD) and distance to agreement (DTA) (3% / 3 mm, 3% / 5 mm, 4% / 4 mm and 5% / 5 mm DD / DTA) are selected for the comparison of planned doses with irradiated dose distributions. The performances of the two dosimetric systems (2D-array and GafChromic films) are compared based on gamma passed percent. This allows the suggestion of the best criteria for the verification of dose distributions.

Issued also as CD