22. RULES OF INT.IMPLANT SYSTEM PARAMETERS MANCHESTER QUIMBY PARIS COMPUTER Linear strength Variable Constant Constant Constant Source distribution Planar implant:(periphery) Area <25 cm- 2/3 Ra; 25-100 cm- ½ Ra; >100 cm- 1/3 Volume implant::Cylinder:belt-4 parts,core-2,end-1 Sphere:shell-6,core-2 Cube :each side-1,core-2 Uniform Uniform Uniform Line sources parallel planes Uniform Line sources Parallel or cylinderic volumes Spacing line source Constant approx. 1 cm apart from each other or from crossing ends Same as Manchester Constant, Selective Separation 8-15 mm Constant Selective Crossing needles Required to enhance dose at implant ends Same Crossing needles not used;active length 30-40% longer Crossing needles not used;active length 30-40% longer
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24. PRINCIPLE-MANCHESTER SYSTEM FEATURES DOSE & DOSE RATE 6000-8000 R in 6-8 days (1000 R/day; 40 R/hr) UNIT / USE OF RADIUM mg Ra hr – defined as amount of radium to give specified dose in 1 hr DOSE SPECIFICATION CRITERA Effective minimum dose 10% above absolute minimum dose LINEAR ACTIVITY Variable: 0.66 and 0.33 mg RaEq/cm
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27. PARIS SYSTEM FEATURES DOSE AND DOSE RATE 6000 -7000 cGy in 3-11 days DOSE PRESCRIPTION POINT Average of the minimum doses in the region defined by the source REFERENCE DOSE & DOSE GRADIENT 85 % of the BASAL DOSE 15 % between the Reference dose and the Basal dose RA SOURCE PLACEMENT Reference isodose volume covers the treated volume
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