Stereotactic Radiosurgery (SRS)Stereotactic Radiosurgery (SRS)Jeremy GalleJeremy Galle

BME 281BME 281October 3October 3rdrd 2012 2012

IntroductionIntroduction

• Also called “stereotaxy”Also called “stereotaxy”

• Non-invasive form of “surgery”Non-invasive form of “surgery”• A type of radiation therapyA type of radiation therapy• Called surgery because the results compare to Called surgery because the results compare to

conventional surgeryconventional surgery• A highly precise delivery of radiationA highly precise delivery of radiation

• Accurate to within 1 to 2 mm of targetAccurate to within 1 to 2 mm of target

• Relies on:Relies on:• 3D imaging (such as CT scan)3D imaging (such as CT scan)

• Determine location of targetDetermine location of target• Highly focused gamma ray beamsHighly focused gamma ray beams• Image-guided radiation therapy (IGRT)Image-guided radiation therapy (IGRT)

• Improves accuracy of deliveryImproves accuracy of delivery

• Has broad range of applicationsHas broad range of applications

HistoryHistory

• 1908 1908 - First stereotactic method developed in London by Sir Victor - First stereotactic method developed in London by Sir Victor Horsley and Robert H. ClarkeHorsley and Robert H. Clarke• ““Horsley-Clarke apparatus”Horsley-Clarke apparatus”

• 1930s 1930s - The apparatus kept receiving slight improvements- The apparatus kept receiving slight improvements

• 1947-1949 1947-1949 – Two stereotactic devices used for brain surgery in – Two stereotactic devices used for brain surgery in humanshumans• Henry T. Wycis and Ernest A. Spiegel’s device (American neurosurgeons)Henry T. Wycis and Ernest A. Spiegel’s device (American neurosurgeons)• Lars Leksell’s device (Swedish neurosurgeon) – founded Elekta laterLars Leksell’s device (Swedish neurosurgeon) – founded Elekta later

• 19781978 – American physician Russell A. Brown implemented CT use in – American physician Russell A. Brown implemented CT use in SRSSRS• Foundation for current devicesFoundation for current devices

Treatment applicationsTreatment applications• Brain tumorsBrain tumors• Cancerous and non-cancerousCancerous and non-cancerous• Primary and metastatic – spreadingPrimary and metastatic – spreading

• Arteriovenous malformations (AVMs)Arteriovenous malformations (AVMs)• Tangling of expanded blood vesselsTangling of expanded blood vessels

• Limits blood flowLimits blood flow

• Trigeminal neuralgiaTrigeminal neuralgia• Nerve disorder in faceNerve disorder in face

• Parkinson’s diseaseParkinson’s disease

• TremorsTremors

• EpilepsyEpilepsy

• Much more…Much more…

Current technologyCurrent technology

• Gamma Knife® by ElektaGamma Knife® by Elekta• Uses 192 to 201 beams of highly-focused Uses 192 to 201 beams of highly-focused

gamma raysgamma rays• All beams aim at target regionAll beams aim at target region

• Linear accelerator (LINAC) machinesLinear accelerator (LINAC) machines• Deliver high-energy x-rays = photonsDeliver high-energy x-rays = photons• Uses microwave technology to accelerate Uses microwave technology to accelerate

photonsphotons• Novalis Tx™ by Brainwave AGNovalis Tx™ by Brainwave AG• XKnife™ by IntegraXKnife™ by Integra• Axesse™ by ElektaAxesse™ by Elekta• CyberKnife® by AccurayCyberKnife® by Accuray

• Proton beam machineProton beam machine

ProcessProcess

• Injected with contrasting fluid and medicineInjected with contrasting fluid and medicine

• Patient first gets a CT or MRI scan of the target areaPatient first gets a CT or MRI scan of the target area

• A computer takes the images created and combines them to A computer takes the images created and combines them to form a 3-D map of the target areaform a 3-D map of the target area

• The head frame is then placed on the patient as the operator The head frame is then placed on the patient as the operator sees fitsees fit

• The patient then lies on a special bed that moves backward into The patient then lies on a special bed that moves backward into the machinethe machine• While the bed moves into the machine, beams shoot from all While the bed moves into the machine, beams shoot from all

different directions towards the target area with the guidance of different directions towards the target area with the guidance of the 3-D mapthe 3-D map

ProcessProcess

AdvantagesAdvantages• Able to reach tumors that are unreachable Able to reach tumors that are unreachable

by conventional surgeryby conventional surgery• Stops the growth by altering DNAStops the growth by altering DNA

• No physical cuts involved (non-invasive)No physical cuts involved (non-invasive)

• Extremely accurateExtremely accurate

• Takes less time to complete (30-60 minutes) Takes less time to complete (30-60 minutes) than comparable therapy treatmentsthan comparable therapy treatments

• More effective than comparable therapy More effective than comparable therapy treatmentstreatments

• Cost covered entirely by some medical Cost covered entirely by some medical insurance companies insurance companies

• Less side effects than other treatmentsLess side effects than other treatments

DisadvantagesDisadvantages

• Side effects existSide effects exist• Skin problems in target areaSkin problems in target area• FatigueFatigue• Hair loss in target areaHair loss in target area• HeadachesHeadaches• Brain swellingBrain swelling• Tissue damageTissue damage• More…More…

• Cannot destroy the tumorCannot destroy the tumor• Only stops the growthOnly stops the growth

• Expensive (if not covered by insurance)Expensive (if not covered by insurance)• $12,000 average for 1 treatment$12,000 average for 1 treatment• $55,000 average for 5 treatments$55,000 average for 5 treatments

• Results take timeResults take time• As little as one month to as long as two yearsAs little as one month to as long as two years

Future of the technologyFuture of the technology

• Extremely powerful beams that Extremely powerful beams that disintegrate tumorsdisintegrate tumors• Alter DNA so particles dissolve Alter DNA so particles dissolve

biologicallybiologically

• More accuracyMore accuracy• NoNo surrounding tissue damage surrounding tissue damage

• Much less side effectsMuch less side effects

• Less expensiveLess expensive

• 4-Dimensional mapping4-Dimensional mapping

• Quicker resultsQuicker results

• Quicker procedure timesQuicker procedure times

Accuray CyberKnife®Accuray CyberKnife®

Elekta Gamma Knife®Elekta Gamma Knife®

Proton beamProton beam

Works CitedWorks CitedChen, Viola, Eric Oermann, Saloomeh Vahdat, Jennifer Riben, Simeng Suy, Xia Yu, Sean Collins, and Brian Collins. "CyberKnife with Tumor Tracking: An Effective Treatment for High-Risk Surgical Patients with Stage I Non-Small Cell Lung Cancer." Frontiers in Oncology 2.9 (2012): n. pag. PubMed. Web. 29 Sept. 2012. <http://www.ncbi.nlm.nih.gov/pmc/articles/ PMC3356163/>.Frighetto, Leonardo, Jorge Bizzi, Rafael Annes, Rodrigo Dos Santos Silva, and Paulo Oppitz. "Stereotactic Radiosurgery for Movement Disorders." Surgical Neurology International 3.1 (2012): n. pag. PubMed. Web. 29 Sept. 2012. <http://www.ncbi.nlm.nih.gov/pmc/articles/ PMC3400484/>."Stereotactic Radiosurgery." MedlinePlus. U.S. National Library of Medicine, n.d. Web. 29 Sept. 2012. <http://www.nlm.nih.gov/medlineplus/ency/article/007274.htm>."Stereotactic Radiosurgery Overview." IRSA. N.p., n.d. Web. 29 Sept. 2012. <http://www.irsa.org/radiosurgery.html>."Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT)." Radiology Info. Radiological

Society of North America, n.d. Web. 29 Sept. 2012. <http://www.radiologyinfo.org/en/info.cfm?pg=stereotactic>.

"Stereotactic Surgery." Wikipedia. Wikimedia Foundation, n.d. Web. 29 Sept. 2012. <http://en.wikipedia.org/wiki/Stereotactic_surgery>.Vesper, J., E. Bolke, C. Wille, P. A. Gerber, C. Matuschek, and M. Peiper. "Current Concepts in Stereotactic Radiosurgery - a Neurosurgical and Radiooncological Point of View." European Journal of Medical Research 14.3 (2009): n. pag. PubMed. Web. 29 Sept. 2012. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352064/>.