心脑血管药理食管癌放疗增敏物理课件.ppt

1、Radiocurability of 8-mm A431 tumor xenografts in nude mice.Radiation dose-response curves were generated for local tumor control at 120 days after treatment with radiation alone(open circle),a single dose of C225 plus radiation(open triangle),or three doses of C225 plus radiation(filled square).Erro

2、r bars are 95%confidence intervals on the TCD50.)(2ddFTumor or early reaction normal cell=/=10Late reaction normal cell=/=3)1(exp)(exp2ddddSF)1(exp21ddnSFSFTSF Example:Tumor(/=10)If 0.62=TCP(35x2Gy)=0%not curable If 0.4,then SF TCP=100%always curable)1(),(ddndnBEDexp)1(expBEDddnTSF For a given dose

3、per fraction,the BED is larger for late reacting tissue than tumor or early reacting tissueTo remain BED=constant:onationhypofractiorHDRndionationhyperfractorLDRnd0;0cddndnBED)1(),(Without considering cell proliferation and damage/repair,small fraction dose with large number of fractions seems alway

4、s good for normal tissues,meanwhile it remains similar effect for tumor.Rapid Repopulation of Tumor During RTpotlagttTddnTSF2ln)(exp Example:tlag=21 days,tpot=3 days and =0.3,/=10 After the first 21 days of treatment,the dose loss for one extra day is equals to 0.77 Gy It implies that in the convent

5、ional RT(60 Gy=30 x2Gy week days),the equivalent dose is only 44 Gy exp2ln)(exptumorpotlagBEDttTddnTSF),(2ln)1(),(TttdnBFdnttTdnddndnBEDpotlagpotlagtumorIncomplete Repair of Normal Tissue During RTexp;1112)(repnntTnnh)()(exp2nhdnddnTSF Example:trep=4 hrs,DT=6 hrs,=0.3,/=3 It implies that in the hype

6、r-fractionation RT(60 Gy=30 x2Gy,two fractions per days),the equivalent dose will be 66.5 Gy ),()()1(),(TtdnBFdnhdddndnBEDrepnOARexp)()(exp2OARnBEDhdnddnTSF),(),(),(),(22112211dnBEDdnBEDordnBEDdnBEDOAROARtumortumor),()2,(dnBEDNBEDGy22BFBFdnNTD020406080100020406080Volume(%)Dose(Gy)CordTumorNodesParot

7、idsBrainstem3DCRTIMRTHeartEsophagusLungSpinal CordDose(Gy)Volume100%5025%Volume50 Gy4080Dose(Gy)Volume100%5025%Volume50 Gy4080A specified dose-volume constraint can lead to an infinite number of dose responsesAn infinite number of dose-volume histograms lead to the same responseConstraint:V(d 50 Gy)

8、25%FSUappapeVVVTDVTDeiVVDD/15050/1)()(.aVTDTDaV)()(ln91024.0150350Vp/VDe/D-lung(a=1 1.2)-liver(a=3.12)-rectum(a=8.33)-spinal cord(a=20)Large volume effectSmall volume effectV1V3V2V4D4=100%D3=80%D2=50%D1=20%D2D4D1D3V4V3V2V1VDoseVolumeaiiiiieffaiiieffiiDDVvVVolumeEffectiveDDVvLawPowerDVDVHDVDVHmaxmaxm

9、ax:),(),(D2D4D1D3V4V3V2V1VVeffaiaiiaeffeffeffeffiiDVVVVDEUDDEUDorDoseEffectiveDVDVHDVDVHDVDVH/1/1maxmax:),(),(),(D2D4D1D3V4V3V2V1VDeffVeffaiaiiaeffeffDVVVVDEUDD/1/1maxorganserialdoseEUDaorganparalleldosemeanEUDamin155050ln944.211),(TDTDmEUDTDEUDVNTCPmGyNTCP-Lung(Pneumonitis G3)-Rectum(Severe proctit

10、is G3)TD50TD575.8)()(ln944.2124.1;89.0)()(ln91024.0155050350VTDVTDmaVTDTDaV%975.185.241111),(75.185.38.0702.075.850124.1/11249.1124.1/1maiaiiEUDTDEUDVNTCPGyDVVEUDTCP for N1TCP for N2TCP for N1+N2r r/r r0 Density%Dose%r r0D0=60 GyVVVVDVTCPDVTCPTCP21),(),(21TCPGy dose deficiency in 15%of volume-0%-10%-15%-20%)exp(exp),(),(),(),(2121iiDVDVTCPDVTCPDVTCPDVTCPVVVV rIn the practice,TCP(V,Di)is determined from clinical dose response fittingGyTCPTCD50g g50 50 74.055.078.0),(),(),(15.085.02121VVVVDVTCPDVTCPDVTCP