Chapter 6 External Photon Beams: Physical Aspects - IRSN

476.8 CENTRAL AXIS DEPTH DOSES IN WATER: SAD SETUP6.8.6 Relationship between TMR and PDD A simple relationship between TMR(z,A Q , h ) andcorresponding PDD(z,A,f, h) can be derived from thebasic definitions of the two functions:PDD(z,A,f,h) = 100 D QD PTMR(z,A Q,h) =D QD QmaxIAEA Radiation Oncology Physics: A Handbook for Teachers and Students - 6.8.6 Slide 1 (93/170)6.8 CENTRAL AXIS DEPTH DOSES IN WATER: SAD SETUP6.8.6 Relationship between TMR and PDDD Q= D PPDD(z,A,f,h)100= D QmaxTMR(z,A Q,h) f + z DP = DPPSF( A, h) = DQ PSF( A, h)f+ zmax2D Qmax= D Q PSF(A Q,h)PDD( zAfh , , , ) PSF( Ah , ) f+z TMR( zA ,Q, h) = 100 PSF( AQ, h) f + zmax2IAEA Radiation Oncology Physics: A Handbook for Teachers and Students - 6.8.6 Slide 2 (94/170)