Presentation on theme: "Leia Szwedo In partial fulfillment of RT 412"— Presentation transcript:
1 Respiratory Motion Management Techniques for Chest and Abdominal Radiation Therapy Leia SzwedoIn partial fulfillment of RT 412University of Wisconsin – La Crosse, Radiation Therapy Program
2 BackgroundIssue1:Respiratory motion caused by patient breathing during radiation therapy treatment can cause displacement of the tumor location.12 to 16 respiratory cycles every minuteSI direction: three to 12 millimetersAnterior-posterior and lateral directions: five mmCauses difficulty localizing tumorOverdosing normal tissue, under dosing tumor
3 Background cont. Solution: Respiratory motion management Techniques:Immobilization of the diaphragmBreathing controlReal-time trackingConsensus shows that in comparison to free breathing radiation treatments, all motion management techniques are beneficial in treating moving tumors.2-4minimal statistical differences in motion management between the techniques.2-4
4 Immobilization of the Diaphragm Utilizes devices to compress the abdomenLimit the air intake of the patientThereby reducing the amount the diaphragm can move and the tumor motion associated with it2More precise tumor localization1Smaller margins achievable1
5 Immobilization of the Diaphragm Examples:BodyFix2Dual-vacuum systemMoldPlastic sheetHoseCompression PillowAbdominal Compression Plate5Stereotactic body framePressure plateScrew
6 Immobilization of the Diaphragm Advantages2:SimplicityMinimal technological devicesEasy useReduce respiratory motionReusableDisadvantages2:Increased setup timeSlight discomfort to some patientsDifficult for patients who experience claustrophobia.2
7 Breathing Control Voluntary or machine-regulated breath holds.1 Causes a cession of breathing during the duration that the beam is on.1Commonly used when treating breast, lung, and esophageal cancer.1,3,4Techniques:Deep-inspiration breath-holds (DIBH)Active breathing control (ABC)
8 Breathing Control Deep-inspiration breath-holds (DIBH)1,3,6 Breathing instructions given“Take a deep breath in, and hold it.”Beam is turned on during breath holdPatient instructed to breath when beam is turned offAdvantages:1,3,6No additional equipmentsCost effectiveReduces tumor motionDecrease in cardiac treated volumes (V20 from 26.5 to 22.8 percent) and esophageal treated volumes (V50 from 25.5 to 22.6 percent).9Increased doses and smaller tumor margins are possibleDisadvantages:1,3,6Difficult to determine the breath hold reproducibilityUnrealistic for many elderly or frail patients, or those with pulmonary disease
9 Breathing Control Active breathing control (ABC) Advantages: Mouthpiece placed in the patient’s mouthHooked up the ABC.7,8Continuously monitors lung volumeWhen the lung volume is at the ideal level, usually 70 to 80 percent of maximum inspiration, the valve on the mouthpiece is closed offPrevents the patient from inhaling or exhaling.6-8Ensures breath hold reproduciblity.6-8The radiation beam is turned on, and once the radiation is finished being delivered, the valve is reopened, allowing the patient to resume breathing.6-8Advantages:Guarantees reproducible breath holds3,6,8Reduces tumor motion and cardiac and esophageal treated volumes9Disadvantages:More invasive6,8Patient needs to hold their breath for a minimum of 15 seconds6,8May require verbal training by the therapist6
10 Real-Time Tracking Real time tumor localizations Techniques to track tumor position5:External respiratory surrogatesImplanted radio-opaque fiducial markersSurface imagingOnce the tumor is accurately located, the radiation beam will turn on and begin treating5Examples:Real-time Position Management (RPM) System, AlignRT, and CyberKnife
11 Real-Time Tracking Real-Time Position Management System Utilizes an external respiratory surrogate5A plastic box with infrared reflective markersPlaced on top of the patient’s abdominal surfaceInfrared cameras detect the reflective markers5,10During treatment, the tumor is tracked5When the respiratory location matches the location predetermined, the beam will turn on.When out of the assigned location, the beam turns off
12 Real Time Tracking AlignRT11 Surface imaging Uses two infrared cameras to triangulate the location of the patient and derive depth informationIn order to precisely locate the patient position, an optical pattern is projected onto the patient to identify the corresponding pointsAn algorithm is computed to use the points to create a surface image of the patient.11From the surface image, the therapists can then make shifts to align the image to the original planning image.Throughout the entire treatment, AlignRT tracts the motion, and only allows the continuation of treatment when the tumor location is within the assigned tolerance location.
13 Real-Time Tracking CyberKnife5 Machine moves along with the tumor. Implements a lightweight 6MV linear accelerator fixed on a robotic arm.5A real-time motion system tracks the motion of the tumor, and the robotic arm moves in synchrony to match the movement.5Moves in six degrees of freedom to compensate for the true tumor motion.5However, the beam output, energy and size are limited.5
14 Real-Time Tracking Advantages: Disadvantages Accurate tracking of the tumor.5Intrafractional movement regulation.1,5Non-invasive and excludes rigid frames.5Eliminates patient discomfortRequires no active patient participation.5Patient receives no additional radiation dose.5Infrared laser useDisadvantagesSignificantly increased treatment times5Tumor motion must be assumed to match the surface motion, unless the system uses internal markers.5
15 Clinical Implications Study A2 (Han et al) :Compared:Free Breathing, BodyFix, Abdominal Compression PlateLooked at:Tumor motion and patient comfortResults:Tumor motion:FB = 6.1mmACP = 4.7mmBodyFix = 5.3mmPatient comfort:63% of patients preferred ACP
16 Clinical Implications Study B 3 (STIC 2003 project):Compared:Free Breathing, Active Breathing Control, Deep-Inspiration Breath-Hold, RPMLooked at:Target volumes, toxicities, survival, and local recurrenceResultsGating Vs Free BreathingTarget volumes:FB= 360 232 mlGating=282 176 mlAcute toxicities:no notable difference except for pulmonary (48% FB vs. 36% gating) Late Toxicities:FB=9%Gating =6%Gating TechniquesSurvival: no differenceLocal recurrence:RPM: 13%DIBH= 36.7%ABC= 43.3%
17 Clinical Implications Study C 4 (Massachusetts General Hospital and Harvard Medical School):Compared:Deep-Inspiration Breath-Hold and AlignRTLooked at:ReproducibilityResults:22% of breath holds were out of 5mm toleranceCombined DIBH and AlignRT produce greatest reproducibility for breath holds.
18 ConclusionRespiratory motion management is beneficial in the reduction of intrafractional motionAllows for a decrease in treatment volumes, resulting in a reduction of normal tissue toxicities while giving higher doses to the lesionStill recommended to use interfractional imaging
19 References1. Gilin MT. Special procedures. In: Washinton CM, Leaver D, eds. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier; 2010:2. Han K, Cheung P, Basran PS. A comparison of two immobilization systems for stereotactic body radiation therapy of lung tumors. Radiotherapy & Oncology. 2010;95(1): /j.radonc3. Giraud P, Morvan E, Claude L, et al. Respiratory gating techniques for optimization of lung cancer radiotherapy. Journal of Thoracic Oncology ;6(12): doi: /JTO.0b013e ec2.4. Gierga DP, Turcotte JC, Sharp GC, et al. A voluntary breath-hold treatment technique for the left breast with unfavorable cardiac anatomy using surface imaging. Internation Journal of Radiation Oncology Biology Physics. 2012;84(5): doi: /j.ijrobp5. Giraud P, Houle A. Respiratory gating for radiotherapy: Main technical aspects and clinical benefits. IRSN Pulmonary. 2013(2013). doi: /2013/6. Wong J. Methods to manage respiratory motion in radiation treatment. American Association of Physicists in Medicine Wed site. Accessed January 14, 2014. 7. Saving the heart of breast cancer patients. Mercy Hospital Web site. cancer-patients. March 20, Accessed January 25, 2014.8. Brock J, McNair HA, Panaskis N, et al. The use of the Active Breathing Coordinator throughout radical non-small-cell lung cancer (NSCLC) radiotherapy. International Journal of Radiation Oncology, Biology, Physics. 2011;81(2): doi: /j.ijrobp9. Sager O, Beyzadeoglu M, Dincoglan F, et al. Evaluation of active breathing conrol-moderate deep inspiration breath-hold in definite non-small cell lung cancer radiotherapy. Neoplasma. 2012;59(3). doi: /neo_2012_043.10. Real-time position management system respiration synchronized imaging and treatment. Varian Web site. Accessed January 21, 2014.11. 3D surface reconstruction. VisionRT Web site Accessed January 14, 2014.