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

The purpose of this study is to estimate tumor control probability (TCP) and normal tissue complication probability (NTCP) for estimating the expected clinical gain coming from 3DCRT (3dimension conformal radiotherapy) and IMRT (Intensity Modulated Radiotherapy) in the studied clinical sites which are prostate, breast and head and neck with the impact of the dose calculation algorithm, energy and number of treatment fields. XIO planning system version (4.51.00) has been used in this study supplied with two different calculation algorithms (superposition and convolution), and at 6 and 15 MV photon beam energy. For each clinical site, 12 IMRT plans are created and one conformal plan, IMRT plan were developed for 5, 7 and 9 fields, using both algorithms and both energies. The parameters of evaluation included dose volume parameters, TCP and NTCP. Results show that for prostate case, IMRT technique with 7 fields improve target conformity and provide better organ at risk (rectum and bladder) sparing in comparison with conformal as shown from the results of TCP and NTCP, and with insignificant difference according to energy and used algorithm. For breast case, IMRT technique with 5 fields improve target conformity and TCP in comparison with conformal technique with improvement in NTCP values

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