The IORT Treatment Planning System. radiance. GMV, 2012 Property of GMV All rights reserved

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3 ADVANTAGES OF IORT PRECISION: RT guided by direct vision. PROTECTION: Normal tissues can be displaced. RESECTION: Radiosurgical intensity. radiance, the IOERT TPS 2012/09/24 Page 3

4 DRAWBACKS Visual guidance is not perfect: The setup (applicators, localization, absence of a mirror/camera or not enough light) can difficult the visualization of the area. No anatomic information beneath the viewed surface. Once the tumor has been resected the tumor bed is not clearly identified. Absence of a planning tool to simulate the treatment beforehand and serve as a communication tool with all the stakeholders. Dosimetry simulation methods are simple and do not consider heterogeneity. Experimental measurements for commissioning and periodic QA means a lot of work. Verbal dose prescription and intraoperative decisions. Incomplete information of what you have done. radiance, the IOERT TPS 2012/09/24 Page 4

5 A SIMULATION AND PLANNING TOOL FOR INTRAOPERATIVE RADIOTHERAPY To assist radiation oncologists, surgeons, physicists and other professionals involved in IORT with: A predictive and registered treatment planning for IORT: Dosimetry estimation, calculation and reporting An improved communication to define the radio-surgical decision making process in an individualized approach for a given cancer patient conditions. radiance, the IOERT TPS 2012/09/24 Page 5

6 A CERTIFIED PRODUCT radiance, the IOERT TPS 2012/09/24 Page 6

7 SHORT DESCRIPTION radiance is the only IORT Planning System in the market. Major characteristics are: 3D visualization of the patient image and estimated dose. Dosimetry algorithms (Pencil Beam & Monte Carlo) which deals with heterogeneity of the tissues and reduce the measures to characterize the LINAC. Simulation of different parameters of the procedure (applicator position/orientation, diameter, bevel, energy) adjusted to the particular patient. Delimitation of the tissues. DVH. Simulation of protections, bolus, air. Detailed report which allows accurate registration of the process, pre-, intra- and post-. Easy to use. CE (class IIb) and FDA (class III) certified. radiance, the IOERT TPS 2012/09/24 Page 7

before the procedure PREOP IMAG INTRA IMAG OR PREOP IMAG

9 PLANNING PHASES radiance introduces a new phase, the pre-planning phase: explore the treatment parameters before the procedure PREOP IMAG INTRA IMAG OR PREOP IMAG POST IMAG OR INTRA IMAG radiance, the IOERT TPS 2012/09/24 Page 9

10 INTRAOP IMAGING FOR INTRAPLANNING radiance, the IOERT TPS 2012/09/24 Page 10

11 TRANSPORTATION COACH DONE IN STANDARD CT SCAN Intraoperative image Safe transportation Customizable Fixation of auxiliary arms (applicators) or surgery tools (separators, ) radiance, the IOERT TPS 2012/09/24 Page 11

12 HOW IS IT DONE? FIX THE APPLICATOR IN THE OR TRANSPORT TO THE SCAN SCAN OF THE PATIENT INTRA IMAG radiance, the IOERT TPS 2012/09/24 Page 12

WORKFLOW SEGMENTATION SIMULATION DOSE COMPUTATION Gross

protect Resected Volume (surgery) Tumor bed (PTV) Surgical

position and orientation Select enery which covers the

the dose at the selected percentage covers the target area

13 WORKFLOW SEGMENTATION SIMULATION DOSE COMPUTATION Gross Tumot Volume (GTV) Clinical Tumor Volume (CTV) Organs to protect Resected Volume (surgery) Tumor bed (PTV) Surgical frame Patient orientation Cone diameter and bevel Cone position and orientation Select enery which covers the target volume Use the DVH and 2D/3D images to confirm that the dose at the selected percentage covers the target area protecting the risky healthy areas radiance, the IOERT TPS 2012/09/24 Page 13

15 PATIENT DATABASE radiance, the IOERT TPS 2012/09/24 Page 15

16 GROUPING / FILTERING radiance, the IOERT TPS 2012/09/24 Page 16

17 ACCESS TO PACS radiance, the IOERT TPS 2012/09/24 Page 17

18 3D VOLUMETRIC / MPR REPRESENTATION radiance, the IOERT TPS 2012/09/24 Page 18

19 CONTOURING Pearl CTL+C, CTL+V Redimension Interpolation radiance, the IOERT TPS 2012/09/24 Page 19

898 Lead 8.114 Methacrylate 1.15 Water 1.

20 ASSIGNMENT OF BULK DENSITIES Material Electron density Aluminum Brass Lead Methacrylate 1.15 Water radiance, the IOERT TPS 2012/09/24 Page 20

21 APPLICATOR POSITIONING radiance, the IOERT TPS 2012/09/24 Page 21

22 INTERNAL RESTRICTIONS Anatomical restrictions for applicator manipulation. Surgical restrictions: incisions, retractors, etc. radiance, the IOERT TPS 2012/09/24 Page 22

23 SURGICAL FRAME SIMULATION LIMITS APPLICATOR MOVEMENTS radiance, the IOERT TPS 2012/09/24 Page 23

24 ISODOSE CURVES DISPLAYED radiance, the IOERT TPS 2012/09/24 Page 24

25 DOSIMETRY AND DVH radiance, the IOERT TPS 2012/09/24 Page 25

26 REPORT Create a report of the planning process. Save the settings (applicator position and parameters) radiance, the IOERT TPS 2012/09/24 Page 26

28 BREAST radiance, the IOERT TPS 2012/09/24 Page 28

29 RECTAL CANCER radiance, the IOERT TPS 2012/09/24 Page 29

30 SARCOMA radiance, the IOERT TPS 2012/09/24 Page 30

32 AAPM TF48 & TG72, ICRU 71 radiance, the IOERT TPS 2012/09/24 Page 32

34 PENCIL BEAM ALGORITHM The algorithm use CT-modified stopping and scattering powers relatives to water. With energy independent quotients for patient tissues, the algorithm calculate effective depths and proper Gaussian widths to correct for heterogeneities. Configured with an smaller set of measurements Tested in water phantoms and heterogeneities configurations in one Elekta and one Varian LINAC. radiance, the IOERT TPS 2012/09/24 Page 34

35 EARLY EXPERIMENTS IN WATER 6 cm Bevel 0º 6 MeV 15 cm Bevel 45º 18 MeV 8 cm Bevel 45º 12 MeV Pencil beam for electron intraoperative radiotherapy. Early results from profile and percentage depth dose modelling. AAPM. 52nd Annual Meeting. Philadelphia radiance, the IOERT TPS 2012/09/24 Page 35

36 RESULTS Heterogeneity setup: Solid Water Step. Applicator 8 cm, Bevel 0º, 12 MeV 1,2 1 Normalized Dose 0,8 0,6 0,4 12 mm-film 17 mm-film 12 mm-pencil beam 0,2 17 mm-pencil beam Position (mm) Depth: 12 mm radiance, the IOERT TPS 2012/09/24 Page 36

37 RESULTS Heterogeneity setup: Lung (Chest Wall). Bevel 0º Depth (mm) Film (cgy) Calc. (cgy) Diff. (%) ,0% ,1% ,1% ,3% Bevel 45º Depth (mm) Film (cgy) Calc. (cgy) Diff. (%) ,9% ,2% ,3% ,2% radiance, the IOERT TPS 2012/09/24 Page 37

38 RESULTS Heterogeneity setup: Lung (Mediastinum-Lung). radiance, the IOERT TPS 2012/09/24 Page 38

39 RESULTS Heterogeneity setup: Bone. Applicator 8 cm, Bevel 0º 1,2 1 Normalized Dose 0,8 0,6 0,4 20 MeV-film 20 MeV-pencil beam 6 MeV-film 0,2 6 MeV-pencil beam Position (mm) radiance, the IOERT TPS 2012/09/24 Page 39

40 RESULTS More accurate than others pencil beam algorithms described in the literature for external electron beam. radiance, the IOERT TPS 2012/09/24 Page 40

41 RESULTS Heterogeneity setup: Shielding Disk. The main limitation appeared on top of the shielding disk, because pencil beam algorithm cannot model backscatter radiation. Nevertheless, the modeling of the attenuation underneath the disk was in good agreement with measurements. E (MeV) Film (%) Calc. (%) Diff. (%) 6 2% 0% 2% 20 8% 6% 2% % of dose outside disk radiance, the IOERT TPS 2012/09/24 Page 41

42 RESULTS radiance, the IOERT TPS 2012/09/24 Page 42

44 MONTE CARLO High fidelity simulation. Improve limitations of semiinfinite layer approximation and backscattering modeling. Fast implementation: recode of DPM in parallel C++. Computation time < 5 mins. LINAC configuration without knowledge of the geometry and only by means of measurements. radiance, the IOERT TPS 2012/09/24 Page 44

45 MONTE CARLO FLOW radiance, the IOERT TPS 2012/09/24 Page 45

46 MC Flow: Source Multiple beam energies, applicator diameters and bevel angles are considered For each combination a PS is derived from measurements in a water tank. 100 PDD Diameter:7 Energy:9 Angle:A MeV Beam Dose (a.u.) Water Varian 21EX Γ(2 mm,3%)< Depth (mm) radiance, the IOERT TPS 2012/09/24 Page 46

MC Flow: Source Multiple applicator diameters and bevel angles are considered For each combination a PS is derived from measurements in a water tank.

47 MC Flow: Source Multiple applicator diameters and bevel angles are considered For each combination a PS is derived from measurements in a water tank. 100 Lateral Profile Diameter:7 Energy:9 Angle:A MeV Beam Dose (a.u.) Water Varian 21EX y (mm) radiance, the IOERT TPS 2012/09/24 Page 47

48 MC Flow:Source MeV Phase Space Varian 21EX Probability Density MeV 12 MeV 16 MeV 20 MeV Energy (Mev) Radial Distance (cm) 7 cm Applicator: Broadening & peaking on the edges with energy ISIORT 2012 POSTER: Herranz et al Iterative Reconstruction of Clinical Electron Beam Phase Space for Intra-Operative Radiation Therapy from Measured Dose Data Fluence(a.u.) MeV radiance, the IOERT TPS 2012/09/24 Page 48

49 Hounsfield MC Flow: CT Calibration of each CT is straightforward using an stoichiometric approach Fitting Measurement Heart Lung Ribs Adipose T. radiance, the IOERT TPS 2012/09/24 Page 49

50 MC Flow: Physics Kernel : reimplements the DPM* physics Initial code prototype showed the feasibility of running MC dose estimations in clinical scenarios. Cross sectional tables extended to 25 MeVs Intensive optimizations to speed up (x10) execution Use of computing resources (Threading, Memory layout) Electron transport Particle generation *Sempau et al, Phys. Med. Biol., 2000 Guerra et al., IEEE NSS/MIC, pp3069, 2010 radiance, the IOERT TPS 2012/09/24 Page 50

51 PENCIL BEAM vs. MONTE CARLO Leakage into lung Leakage into lung Computing :1 radiance, the IOERT TPS 2012/09/24 Page 51

52 PENCIL BEAM vs. MONTE CARLO Place Protection: Lead Place Protection: Lead Dose increase Leakage gone Leakage gone Computing :1 radiance, the IOERT TPS 2012/09/24 Page 52

53 MONTE CARLO CONCLUSIONS Defined flow for MC LINAC + CT characterization Volume definition: Patient + objects Coupled to the TPS Fast execution 1 : Breast Example 4% 6cm/6 MeV Feasible for all pre/intra/post planning New era in IOERT dosimetry: precise view of radiation-matter interaction Therapy will be more predictable and accurate. radiance, the IOERT TPS 2012/09/24 Page 53

55 PROPOSED LINAC MODEL WORKFLOW 1. Experimental measurements are introduce to model the beam of the LINAC by means of a LINAC characterization tool. 2. Physicists can review the verification and fitting of the model by means of provided tools: 1. Profiles comparison 2. Gamma function 3. Statistics info radiance, the IOERT TPS 2012/09/24 Page 55

REDUCED SET OF MEASUREMENTS FOR PB CHARACTERIZATION Absolute doses (cgy/mu) measured in water at three different SSD at the

Also, for the rest of bevels, absolute dose at the standard SSD and the depth of the maximum for all diameters and energies.

Water profiles for a medium field size and bevel 0º for each energy at the depths of 3 mm, R100 and R50.

56 REDUCED SET OF MEASUREMENTS FOR PB CHARACTERIZATION Absolute doses (cgy/mu) measured in water at three different SSD at the depth of the maximum, for an applicator of 0º for all diameters and energies. Also, for the rest of bevels, absolute dose at the standard SSD and the depth of the maximum for all diameters and energies. PDD ranges (R100, R50, Rp) measured in water for each diameter, bevel angle and energy. Water profiles for a medium field size and bevel 0º for each energy at the depths of 3 mm, R100 and R50. Air profiles with gaps of 50, 100 and 150 mm for a medium field size and bevel 0º for each energy. Also, an additional air profile with a gap of 20 mm for the rest of diameters. radiance, the IOERT TPS 2012/09/24 Page 56

57 PROPOSED LINAC MODEL WORKFLOW CT SCANNER CHARACTERIZATION CT conversion table and tissue characterization curve radiance, the IOERT TPS 2012/09/24 Page 57

LINAC CONFIGURATION TOOL Input tool to introduce measurements to model the LINAC. Easy introduction of measurements from a water phantom software.

58 LINAC CONFIGURATION TOOL Input tool to introduce measurements to model the LINAC. Easy introduction of measurements from a water phantom software. Comparisons charts of measurements vs. computed (PB). Adjustment parameters for better characterization. CT-Density Scanner calibration table can be configured as well. radiance, the IOERT TPS 2012/09/24 Page 58

59 INTRODUCTION OF PARAMETERS radiance, the IOERT TPS 2012/09/24 Page 59

60 MODEL VS MEASUREMENTS radiance, the IOERT TPS 2012/09/24 Page 60

RT Structure Set RT Plan RT Treatment Record Adaption of

62 DICOM.RT EXPORT Capability to export in DICOM.RT format, the following information: RT Image RT Dose RT Structure Set RT Plan RT Treatment Record Adaption of DICOM.RT standard for IORT. radiance, the IOERT TPS 2012/09/24 Page 62

63 AUTOMATIC SEGMENTATION Segmentation is a time consuming activity which is normally incompatible with intra-planning. Different techniques are being investigated and under clinical evaluation. radiance, the IOERT TPS 2012/09/24 Page 63

64 INTRAOP TRACKING OBJECTIVES Relate the patient in the OR table with his/her previous CT Know the exact position/orientation of the applicator. With respect to previous CT = guidance using preplaning With respect to virtual representation of the LINAC setup = know LINAC position parameters (angle/position of each axis of movement, such as gantry, LINAC table, etc.). Confirm safe treatment position. Confirm readiness of treatment to proceed with intraop imaging (if available). radiance, the IOERT TPS 2012/09/24 Page 64

65 TRACKING TECHNOLOGIES IN EBRT radiance, the IOERT TPS 2012/09/24 Page 65

66 TRACKING IN IORT Patient and cone position registered to previous CT with an error of a few millimeters. Virtual docking before it is being done. radiance, the IOERT TPS 2012/09/24 Page 66

67 INTRA-IMAG WITH CONVENTIONAL CT FIX THE APPLICATOR IN THE OR TRANSPORT TO THE SCAN SCAN OF THE PATIENT INTRA IMAG radiance, the IOERT TPS 2012/09/24 Page 67

68 C-ARM WITH 3D CAPABILITIES Ziehm Vision (FD) Vario 3D radiance, the IOERT TPS 2012/09/24 Page 68

69 DOSIMETRY IN INTRA IMAGE radiance, the IOERT TPS 2012/09/24 Page 69

Pre CT & Intra CT or Intra CT and Post CT. Sum EBRT plus IOERT dose.

70 IMAGE REGISTERING Pre MRI, PET, CT. Helps contouring. Pre CT & Post CT. Evaluate the results of the surgery. Pre CT & Intra CT or Intra CT and Post CT. Sum EBRT plus IOERT dose. Intraoperative registration. Video registration. RIGID REGISTRATION NON-RIGID REGISTRATION radiance, the IOERT TPS 2012/09/24 Page 70

THANK YOU Carlos Illana cillana@gmv.es www.

Transitioning from pencil beam to Monte Carlo for electron dose calculations

Transitioning from pencil beam to Monte Carlo for electron dose calculations Jessie Huang-Vredevoogd (jyhuang4@wisc.edu) University of Wisconsin NCC AAPM October 12, 2019 1 Topics to cover Background RayStation