MISTREAT: MotIon Simulator in proton-therapy TREATment. Paul Morel - PowerPoint PPT Presentation

MISTREAT: MotIon Simulator in proton-therapy TREATment. Paul Morel February, 27 2014 Workshop on Bioinformatics and Stringology 2014 Advisors: Guillaume Blin, PhD (LIGM, Universit´ e Paris-Est Marne La Vall´ ee, France) St´ ephane Vialette, PhD (LIGM, Universit´ e Paris-Est Marne La Vall´ ee, France) Xiaodong Wu, PhD (University of Iowa, USA) Paul Morel MISTREAT February, 27 2014 1 / 34

Radiation Therapy Radiation Therapy Cancer treatment relying on radiations aiming at killing cancerous cells. Examples of radiation therapy modalities: Paul Morel MISTREAT February, 27 2014 2 / 34

Radiotherapy and Proton-Therapy Radiotherapy External X-ray (photon) cone beam rotating around a patient. Proton-therapy External beam of protons rotating around a patient, stopping at specific angles to deliver a prescribed treatment. Paul Morel MISTREAT February, 27 2014 3 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Paul Morel MISTREAT February, 27 2014 4 / 34

Proton-Therapy Why protons? Figure 1: Comparison of spinal fields for medullblastoma: photons (upper panels) versus protons (lower panels) [ ? ] Paul Morel MISTREAT February, 27 2014 5 / 34

Proton-Therapy Why not only protons? Paul Morel MISTREAT February, 27 2014 6 / 34

Proton-Therapy Protons - a summary Water pressure = Proton energy = depth of Bragg Pic Water quantity = Dose = Number of protons Some water drops are deposited on the way = Some dose too Dose is cumulative along the way Paul Morel MISTREAT February, 27 2014 7 / 34

Proton-Therapy Protons - a summary Water pressure = Proton energy = depth of Bragg Pic Water quantity = Dose = Number of protons Some water drops are deposited on the way = Some dose too Dose is cumulative along the way Paul Morel MISTREAT February, 27 2014 7 / 34

Proton-Therapy Protons - a summary Water pressure = Proton energy = depth of Bragg Pic Water quantity = Dose = Number of protons Some water drops are deposited on the way = Some dose too Dose is cumulative along the way Paul Morel MISTREAT February, 27 2014 7 / 34

Proton-Therapy Protons - a summary Water pressure = Proton energy = depth of Bragg Pic Water quantity = Dose = Number of protons Some water drops are deposited on the way = Some dose too Dose is cumulative along the way Paul Morel MISTREAT February, 27 2014 7 / 34

Proton-Therapy Protons - a summary Water pressure = Proton energy = depth of Bragg Pic Water quantity = Dose = Number of protons Some water drops are deposited on the way = Some dose too Dose is cumulative along the way Paul Morel MISTREAT February, 27 2014 7 / 34

Proton-Therapy Pencil Beam Discrete Scanning Paul Morel MISTREAT February, 27 2014 8 / 34

Proton-Therapy Pencil Beam Discrete Scanning The beam is turned off between the spot positions Paul Morel MISTREAT February, 27 2014 8 / 34

Proton-Therapy Pencil Beam Discrete Scanning The beam is turned off between the spot positions Paul Morel MISTREAT February, 27 2014 8 / 34

Proton-Therapy Treatment Planning Treatment Planning Paul Morel MISTREAT February, 27 2014 9 / 34

Proton-Therapy Treatment Planning Treatment Planning Paul Morel MISTREAT February, 27 2014 10 / 34

Proton-Therapy Treatment Planning Treatment Planning Paul Morel MISTREAT February, 27 2014 11 / 34

Proton-Therapy Treatment Planning Treatment Planning Plan: ... Step k: Energy, x coordinate , y coordinate, duration ... Paul Morel MISTREAT February, 27 2014 12 / 34

Proton-Therapy Treatment Planning Treatment Planning Plan: ... Step k: Energy, x coordinate , y coordinate, duration ... Paul Morel MISTREAT February, 27 2014 12 / 34

Proton-Therapy Treatment Planning Treatment Planning Plan: ... Step k: Energy, x coordinate , y coordinate, duration ... Paul Morel MISTREAT February, 27 2014 12 / 34

Proton-Therapy Treatment Planning Treatment Planning Plan: ... Step k: Energy, x coordinate , y coordinate, duration ... Paul Morel MISTREAT February, 27 2014 12 / 34

Proton-Therapy Treatment Planning Treatment Planning Plan: ... Step k: Energy, x coordinate , y coordinate, duration ... Paul Morel MISTREAT February, 27 2014 12 / 34

Proton-Therapy Motion Sensitivity to motion Paul Morel MISTREAT February, 27 2014 13 / 34

Proton-Therapy Motion Sensitivity to motion Inter-fraction motions: loss/gain of weight, tumor swelling/shrinkage, bladder, intestinal gas... Intra-fraction motions: breathing, heart beat ... ⇒ Interplay Effect Figure 2: Results of irradiations without (left) and with (right) motion on a radiographic film.[ ? ] ⇒ Overall treatment degraded Paul Morel MISTREAT February, 27 2014 14 / 34

Proton-Therapy Motion Motion mitigation - Gears During treatment planning: chose beam direction, use several beams, safety margins. Motion reduction: Abdominal press Anesthesia Fixation devices Breathing control techniques (Breath-Holding + Gating) Paul Morel MISTREAT February, 27 2014 15 / 34

Proton-Therapy Motion Motion mitigation - Gears During treatment planning: chose beam direction, use several beams, safety margins. Motion reduction: Abdominal press Anesthesia Fixation devices Breathing control techniques (Breath-Holding + Gating) Paul Morel MISTREAT February, 27 2014 15 / 34

Proton-Therapy Motion Motion mitigation - Gears During treatment planning: chose beam direction, use several beams, safety margins. Motion reduction: Abdominal press Anesthesia Fixation devices Breathing control techniques (Breath-Holding + Gating) Paul Morel MISTREAT February, 27 2014 15 / 34

Proton-Therapy Motion Motion mitigation - Gears During treatment planning: chose beam direction, use several beams, safety margins. Motion reduction: Abdominal press Anesthesia Fixation devices Breathing control techniques (Breath-Holding + Gating) Paul Morel MISTREAT February, 27 2014 15 / 34

Proton-Therapy Motion Motion mitigation Rescanning (for interplay effect): One energy slice: Iso-Layered Repainting Scaled Repainting Dose per spot visit is kept under an The prescribed dose of every spots is upper limit. It is characterized by divided by a constant N (repainting t max the time limit per spot per visit. factor:number of repaintings). Applicable to the whole volume. Paul Morel MISTREAT February, 27 2014 16 / 34

Proton-Therapy Motion A GPS for the body: Calypso (Varian) Paul Morel MISTREAT February, 27 2014 17 / 34

Proton-Therapy Motion A GPS for the body: Calypso (Varian) Paul Morel MISTREAT February, 27 2014 17 / 34

Proton-Therapy Motion A GPS for the body: Calypso (Varian) Paul Morel MISTREAT February, 27 2014 17 / 34

Proton-Therapy Simulator MISTREAT: MotIon Simulator in proton-therapy TREATment Paul Morel MISTREAT February, 27 2014 18 / 34

Proton-Therapy Simulator Overview Simulator overview Main objective Quantify the impact of intra-fraction motions for given treatment plans. ⇒ Choice of the most robust plan. Implemented in Python with subroutines is C. Paul Morel MISTREAT February, 27 2014 19 / 34

Proton-Therapy Simulator Patient Data Patient data Patient data: conversion CT # to mass densities and structure set information. Paul Morel MISTREAT February, 27 2014 20 / 34

Proton-Therapy Simulator Physical Data Physical Data Depth dose curve generated from dose distributions in a water tank simulated in RayStation (RaySearch lab.) for energies ranging from 30MeV to 225MeV (step 5MeV). Missing energies: Approximation of the depth-dose curve from computed data. Paul Morel MISTREAT February, 27 2014 21 / 34

Proton-Therapy Simulator Dose calculation for heterogeneous media Dose calculation for heterogeneous media Analytical model[ ? ],[ ? ]: Main functions Auxiliary functions d ( x , y , z ) = S m � w σ 2 size + σ pt ( z ) 2 C ( z ) O ( x , y , z ) σ tot ( z ) = ρ m w σ pt ( z ) = y 0 ( rpl ( z )) � 2 � ssd 0 + rpl ( z ) C ( z ) = DD w ( rpl ( z ) , E 0 ) ∗ � t � t z � 2 � �� y 0 ( t ) = y 0 ( R ) ∗ 0 . 69 ∗ + 0 . 33 R R x 2 + y 2 1 � � O ( x , y , z ) = 2 π ( σ tot ( z )) 2 ∗ exp − 2( σ tot ( z )) 2 y 0 ( R ) = 0 . 12085 × 10 − 4 ∗ R 2 + 0 . 02275 ∗ R Paul Morel MISTREAT February, 27 2014 22 / 34

Proton-Therapy Simulator Model evaluation Model evaluation Comparison to RayStation results: Single beamlets in water tank, energies from 30MeV to 225MeV: Dose profile of Bragg Peak: Comparison mean (mm) min(mm) max(mm) std. dev.(mm) RaySt. vs Simul. 1 . 1 0 2 . 73 1 . 15 Table 1: Absolute difference between the BP locations. Paul Morel MISTREAT February, 27 2014 23 / 34