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VarianIMRT IMRT MLC LMC VARIAN ONCOLOGY SYSTEMS
Varian装置によるIMRT 品質担保の為に必要な作業 Changes Over Time: ICRU 50 to 62 IRRADIATED VOLUME TREATED VOLUME PTV ITV CTV GTV PRV: Includes margin around the OAR to compensate for changes in shape and internal motion and for set-up variation. OAR IAEA 再現在のある患者固定法の選択 マージンの決定 近畿大学 奥村先生からの資料より VARIAN ONCOLOGY SYSTEMS PRV 必要な輪郭の指示 ICRU50/62 線量制約の統一
IMRT Contouring Field Setup (Optional) BAO Optimization Fluence Optimization Objectives Optimal Fluence VARIAN ONCOLOGY SYSTEMS
IMRT Optimal Fluence LMC Parameters Leaf Motion Calculation MLC Parameters AAA, PBC, Acuros XB algorithm Actual Fluence 3D dose calculation Leaf Motions Delivery VARIAN ONCOLOGY SYSTEMS
IMRT Only b5mm VARIAN ONCOLOGY SYSTEMS
IMRT IMRTRapidArc NTO IMRT Relative number (0 1000) Defines importance of the objective VARIAN ONCOLOGY SYSTEMS
IMRT Upper Objective Lower Objective Objectives on a Line VARIAN ONCOLOGY SYSTEMS
IMRT Objective - Function CF = N i=1 ( u( D min d i ) 2 + o( d i D max ) 2 ) 不足線量での評価 不足線量 過線量の項において指定線量の 範囲外は評価しないようにしておく 過線量での評価但し :i= 指定した腫瘍 N= 腫瘍内のボクセル数 d= 線量! u= アンダードーズの係数! p= 指定線量! Dmin= 腫瘍内最少線量 CF= 評価関数 o= オーバードーズの係数 Dmax= 腫瘍内最大線量 VARIAN ONCOLOGY SYSTEMS
IMRT Objective - Function CF = p k N k ( d i,k D max,k ) 2 i=1 臓器毎のペナルティー リスク臓器内のボクセルの線量 許容線量 ( 最大線量 ) 但し :k= 臓器! i= ボクセル数! p= ペナルティー係数! N= 登録臓器数! d= ボクセル線量! Dmax= 最大線量! VARIAN VARIAN ONCOLOGY SYSTEMS!10
IMRT Normal Tissue Objective VARIAN ONCOLOGY SYSTEMS
IMRT Normal Tissue Objective (NTO) f (r) = $ & % '& f 0 e k(r r start ) + f (1 e k(r r start ) ), r r start f 0, r < r start Where r = Distance from target border r start = start of fall off f 0 = start dose (%) f = end dose (%) k = Fall off VARIAN ONCOLOGY SYSTEMS
IMRT Smoothing Objectives XY XVarian MLCMU YMUTongue & Groove VARIAN ONCOLOGY SYSTEMS
IMRT Minimize Dose Objective Normal Tissue Objective VARIAN ONCOLOGY SYSTEMS
IMRT Optimization Parameters Beamlet (IMRT)! Base dose plan Maximum number of iterations Maximum optimization time VARIAN ONCOLOGY SYSTEMS
IMRT Point SamplingCalculation Grid IMRT VARIAN ONCOLOGY SYSTEMS
IMRT Point SamplingCalculation Grid VARIAN ONCOLOGY SYSTEMS
IMRT Optimization - Volume Representation EIP VARIAN ONCOLOGY SYSTEMS
IMRT Optimization - Field Representation Ray trace!!! row = leaf pair! Size of the beamlet Leaf width x 2.5 mm VARIAN ONCOLOGY SYSTEMS
IMRT Optimization - Target Masking 0.5cm 0.5cmY VARIAN ONCOLOGY SYSTEMS
IMRT Optimization - Dose Computation EclipseTarget Masking PointBeamlet Dose at point - d i, Beamlet Beamlet - x j VARIAN ONCOLOGY SYSTEMS
IMRT Penalty Calculation A C B 2 1 p1 > 40 w1 = 100 p2 < 20 w2 = 50 A C B 1 2 Next iteration A B C 1 2 d 37 41 38 22 23 (d 9 1 4 4 9 violate? 1 0 1 1 1 penalty 900 0 400 200 450 Σ 1300 650 A B C 1 2 d 38 40 39 21 22 (d 4 0 1 1 4 violate? 1 0 1 1 1 penalty 400 0 100 50 200 Σ 500 250 Gain 800 400 VARIAN ONCOLOGY SYSTEMS
IMRT Objective function ()! F obj = F PTV + F Critical + F NTO + F SmoothXY! allptvs allcs Fields! () + F Min.Dose Fields VARIAN ONCOLOGY SYSTEMS
Intermediate Dose Calculation MRDC VARIAN ONCOLOGY SYSTEMS
Segment Leaf Motion Calculator optimal fluenceactual fluence LMC Sliding Window Multiple Static Segments None Field size definition VARIAN ONCOLOGY SYSTEMS
Segment Large Field IMRT スプリットフィールド ( フィールド分割 ) 幅の広い照射野を左右二つの分割された照射野に変更をする その際 インテンシティーのつながりを考慮して分割する Paul Keall et. al. Virginia Commonwealth University Medical College of Virginia Hospital VARIAN VARIAN ONCOLOGY SYSTEMS
Segment Large Field IMRT LargeIMRT VARIAN ONCOLOGY SYSTEMS
RapidArc Contouring Auto adjust Field Setup Machine Parameters Optimization Leaf Motions MU per deg MRDC Objectives VARIAN ONCOLOGY SYSTEMS
RapidArc Leaf Motions MU per deg AAA or Acuros XB 3D dose calculation Delivery VARIAN ONCOLOGY SYSTEMS
VMAT Create Couch Structure Couch structures may be added to account for attenuation of the treatment couch. Numerous Varian couches are available Rails can be positioned in or out, for both left and right Couch position may be adjusted VARIAN ONCOLOGY SYSTEMS
VMAT Constraints - Varian Delivery Platforms RT Administration Dose rate / 0.1 MU/deg VARIAN ONCOLOGY SYSTEMS
VMAT Geometry 30 Avoidance sectors VMAT Field size Collimator, Couch rotation Isocenter Arc geometry tool VARIAN ONCOLOGY SYSTEMS
VMAT Avoidance Sectors 2 0 15 VARIAN ONCOLOGY SYSTEMS
VMAT RapidArc - Arc Optimization Progressive Resolution Optimization (PRO) Starts with few directions (control points) Optimizes the MLC motion, Dose Rate, Gantry Speed for each control point Respects MLC, Gantry Speed Constraints () VARIAN ONCOLOGY SYSTEMS
VMAT Progressive resolution () Control Points resolution multi-resolution Calculation direction for arc segment VARIAN ONCOLOGY SYSTEMS
VMAT Steps PRO3 resolution level VARIAN ONCOLOGY SYSTEMS
(AcurosXB) Monte Calo f(x,v,t)x,vf(x,v,t)dxdv dxdv!"!" +!!"!" +!!!"!" =!!!!!!!!"Ω!!! v v VARIAN ONCOLOGY SYSTEMS
(AcurosXB) Monte Calo VARIAN ONCOLOGY SYSTEMS
(AcurosXB) Monte Calo VARIAN ONCOLOGY SYSTEMS
(AcurosXB) Monte Calo q γ prim q γ sec q e cont Initial Phase Space q γγ unc q γe unc q ee unc Modified Phase Space VARIAN ONCOLOGY SYSTEMS
(AcurosXB) Monte Calo VARIAN ONCOLOGY SYSTEMS
より正確な線量計算(AcurosXB) Monte Calo等価な線量計算 不均質層での結果 Monte Carlo計算と同等の結果 5cm 2cm 8cm 6MV, 5x5cm 4cm 11cm 5cm(Water) 8cm(Lung) 2cm(Titanium) VARIAN ONCOLOGY SYSTEMS 11cm(Water) 4cm(Bone)
IMRT VARIAN ONCOLOGY SYSTEMS
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270 3 MLC COPYRIGHT 2010 VARIAN MEDICAL SYSTEMS
Clinac Beam 4 270 6 Stand Gantry
Clinac Beam 4 7 VARIAN ONCOLOGY SYSTEMS Stand Gantry
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3/2
0 0 0
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x E E x =E 0 sin { (z / c t)} H y =H 0 sin { (z / c t)} z E 0 /H 0 = / (376.7 c=1 / y H EH S = E H z E x =E 0 sin { (z / c + t)} B y = B 0 sin { (z / c + t)} 17 VARIAN ONCOLOGY SYSTEMS
TM 010 Ez 2b z 2b E 0 Ez d r Ez z r =b 0 d V=E 0 d/2 d/2 d/2 d/2 cos t dz =E 0 cos z/v+ t 0 dz =V 0 T cos t 0 t=t 0 z=0 V 0 =E 0 d T =sin d d <1 2v 2v T 18 VARIAN ONCOLOGY SYSTEMS
1/2 (1) (2) (3) (4) (1) 19 VARIAN ONCOLOGY SYSTEMS
2/2 (5) (2) (7) (8) (1) Z 20 VARIAN ONCOLOGY SYSTEMS
1 1 1/4/2 /2 1/32/3 2/3 21 VARIAN ONCOLOGY SYSTEMS
A B C D 2b z d
/2 g t=0 t= 1 4 T 0 t= 1 2 T 0 T 0 1/f A B C D
/2 0Z
1 Z=E 02 P 2 ZT 2 (E 0 T) 2 P 2 E 0 T P 27 VARIAN ONCOLOGY SYSTEMS
2 (1) (2) T 5060 M/m 100 M/m 28 VARIAN ONCOLOGY SYSTEMS
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1 10MeV 6MeV 4MeV 1 V= 1+ 2 LPZT 2 ilzt 2 L m ZT 2 /m P 1 P 2 P 3 A 30 VARIAN ONCOLOGY SYSTEMS
2 Buncher Section RF Regular Section ~0.4m ~1m 31 VARIAN ONCOLOGY SYSTEMS
2 Buncher Section RF Regular Section ~0.4m ~1m 32 VARIAN ONCOLOGY SYSTEMS
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Achromatic Bending Magnet System 34 VARIAN ONCOLOGY SYSTEMS
270 C-Series HE Clinac X
270 TrueBeam X
e 2a B 2b 2d z 37 VARIAN ONCOLOGY SYSTEMS
B F = e B B 2 = B(z) d z 1 dz 1 P / e 1 = B(z)dz P / e - 8 = 10-6 1 5 P / e 1 2 abni a 2 +d 2 e z 1 z 2 B z E = 10 (MeV) a = 0.1(m)b = 0.1(m) d = 0.1(m)nI = 100(A) B = P / e = 0.035(Tm) B y (0) = 4.610-4 (T) 2.3mrad 38 VARIAN ONCOLOGY SYSTEMS
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