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10th Annual Lung Cancer Conference Radiation Oncology
Advances in Radiation Oncology for Lung Cancer Treatment John Mansueti, MD PRMC Radiation Oncology 12 Mar, 2015 1
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Disclosures None, but always looking!
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Objectives Describe the role of 4-dimension (4-D) CT scanning in radiation lung treatment planning. Describe the two techniques of stereotactic body radiation therapy: Non-coplanar Intensity Modulated Radiation Therapy and Volumetric Modulated Arc Therapy. Compare the expected local control rates for early stage lung cancer with SBRT and surgery.
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What is Radiation Therapy?
Using ionizing radiation to achieve lethal damage to target tissues The radiation causes lethal breaks in the cells DNA
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Linear Accelerator (LINAC)
Delivers high energy X-Rays (photons) or electrons to the patient’s tumor Our treatment plans try to maximize dose to the tumor while minimizing dose to normal tissue Modern techniques include IMRT, IGRT, SRS, SBRT
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How does a LINAC Work Microwaves accelerate electrons to extremely high speeds and slam them into a metal target High energy x-rays are produced by this collision The x-rays are shaped using several methods as they exit the machine to conform to the target
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Why do we need SBRT? LC with SBRT is 92-97% Radiation Modality
5-year Overall Survival Conventional RT 20% SBRT 42% Radiother Oncol 2010
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Problem Lung tumors move a lot with respiration
≈40% lung tumors move >0.5cm ≈10-15% lung tumors move >1.0cm How can we target a lung tumor more accurately with tight margins to minimize toxicity to normal lung?
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Advanced Imaging 4-D CT scan 4-D PET/CT Cone Beam CT MRI Fusion
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4-D CT Scan Advances in technology have made CT scanning much faster and accurate Traditional CT scan only images the tumor at one point of the breathing cycle Many 3-D CT sets are obtained corresponding to a particular breathing phase
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4D CT
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4-D CT Scan Over-sampling images at every position of interest along the patients axis Images are tagged with breathing signals Images are sorted retrospectively based on corresponding breathing signal
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MIP (Maximum Intensity Projection)
MIP reduces the multiple 3-D CT images from a 4-D data set into a single 3-D data set MIP represents the maximum intensity encountered by the corresponding voxels in all the individual 3-D phase image sets of the 4-D image set.
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MIP CT Slice MIP
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MIP
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MIP
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Cone Beam CT Acquires real-time 3D images of the patient while on the treatment table with a single rotation of the gantry Patient can be adjusted immediately to align tumor target Response of tumor to treatment can be monitored
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Cone Beam CT
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CT-PET/CT Fusion
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Optimal Radiation Treatment
Encompass the tumor with a very conformal dose cloud with rapid dose fall-off outside your target Minimize tumor motion to allow smaller treatment field, thus minimizing dose to normal tissue Verify patient positioning with immediate imaging
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Modern Techniques IMRT-Intensity Modulated Radiation Therapy
VMAT-Volumetric Arc Therapy IGRT-Image Guided Radiation Therapy SBRT-Stereotactic Body Radio-Therapy
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SBRT Advances in hardware (imaging), software innovation (computational algorithms), and faster computer processors have enable development of SBRT techniques. SBRT involves highly precise, high dose, short course treatments (3-5 fractions) SBRT allows precise targeting and techniques to minimize tumor motion
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Multiple Treatment Directions
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Highly Conformal Dose
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Critical Structures Avoided
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RapidArc VMAT (Volumetric Modulated Arc Therapy) is a new radiation technique using sophisticated treatment plan to deliver a continuous beam (arc) of radiation as the linear accelerator rotates around patient
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RapidArc Planning optimization algorithm that simultaneously changes 3 parameters during treatment Shape of treatment aperture delivered dose intensity Speed of gantry rotation Treatment time is very rapid
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RapidArc Conformal Dose
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RapidArc Conformal Dose
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Patient E.D. 68 y/o M was found to have a left sided pulmonary nodule after presenting with cough Biopsy Lung Adenocarcinoma Plan: 4800 cGy in 4 fractions (1200 cGy per fraction)
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Local obliteration CT CT
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Patient A.H. 78 F had a COPD exacerbation and imaging in Jan 2012 revealed RLL nodule Biopsy: Lung Adenocarcinoma Plan: 5400 cGy in 3 fractions
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CT February 2013 CT March2014
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Patient E.M. 73 y/o M with hx of LUL NSCLC s/p resection in 2011 with new RUL 2cm nodule in Jan 2013 (PET hot 5.3 SUV) Biopsy caused penumothorax and path showed atypical cells Plan: 5000 cGy in 5 fractions (1000 cGy per fraction)
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CT CT
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SBRT Results Phase 2 multicenter study of 59 pts with T1 or T2 inoperable early stage tumors (medical condition precluded resection) 3 SBRT treatments (18Gyx3=54 Gy) Local control 97% Local/Regional Control 87% 3-year OS 56% Median OS 48 months Timmerman et al., JAMA 2010
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Summary Advanced Imaging has revolutionized targeting in Radiation Oncology Modern radiation techniques have enabled dose escalation and excellent local control SBRT is an excellent option for patients who are not surgical candidates or refuse surgery
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QUESTIONS?
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