Stereotactic Stereotactic RadiosurgeryRadiosurgery

Jimmy JohannesJimmy Johannes

Physics 335 – Spring 2004Physics 335 – Spring 2004

Final PresentationFinal Presentationhttp://www.sdgkc.com/

http://www.sdgkc.com/

OutlineOutline Case StudyCase Study What is Stereotactic Radiosurgery?What is Stereotactic Radiosurgery?

Stereotactic LocalizationStereotactic Localization RadiosurgeryRadiosurgery ApplicationsApplications

Different technologiesDifferent technologies Gamma KnifeGamma Knife LINAC-based systemsLINAC-based systems CyberKnifeCyberKnife

Case StudyCase Study Imagine…Imagine…

You’re an undergrad at NU…You’re an undergrad at NU… As you approach Finals Week you acquire As you approach Finals Week you acquire

the following symptoms:the following symptoms: HeadachesHeadaches NauseaNausea

Searle? Searle? Mono Mono Evanston Northwestern Healthcare Evanston Northwestern Healthcare MRI MRI

MRI Result:MRI Result:

http://splweb.bwh.harvard.edu:8000/pages/papers/kaus/radiology2001/5a.gif

Diagnosis and TreatmentDiagnosis and Treatment

Diagnosis: Benign Brain TumorDiagnosis: Benign Brain Tumor Treatment:?Treatment:?

Chemo/Immuno therapyChemo/Immuno therapy Invasive brain surgeryInvasive brain surgery Non-invasive radiotherapyNon-invasive radiotherapy Non-invasive stereotactic radiosurgeryNon-invasive stereotactic radiosurgery

Diagnosis and TreatmentDiagnosis and Treatment

Diagnosis: Benign Brain TumorDiagnosis: Benign Brain Tumor Treatment:?Treatment:?

Chemo/Immuno therapy Chemo/Immuno therapy Blood Brain Blood Brain BarrierBarrier

Invasive brain surgery Invasive brain surgery Non-invasive radiotherapyNon-invasive radiotherapy Non-invasive stereotactic radiosurgeryNon-invasive stereotactic radiosurgery

Diagnosis and TreatmentDiagnosis and Treatment

Diagnosis: Benign Brain TumorDiagnosis: Benign Brain Tumor Treatment:?Treatment:?

Chemo/Immuno therapy Chemo/Immuno therapy Blood Brain Blood Brain BarrierBarrier

Invasive brain surgery Invasive brain surgery High Risk High Risk Non-invasive radiotherapyNon-invasive radiotherapy Non-invasive stereotactic radiosurgeryNon-invasive stereotactic radiosurgery

Diagnosis and TreatmentDiagnosis and Treatment

Diagnosis: Benign Brain TumorDiagnosis: Benign Brain Tumor Treatment:?Treatment:?

Chemo/Immuno therapy Chemo/Immuno therapy Blood Brain Blood Brain BarrierBarrier

Invasive brain surgery Invasive brain surgery High Risk High Risk Non-invasive radiotherapy Non-invasive radiotherapy Too Non- Too Non-

SpecificSpecific Non-invasive stereotactic radiosurgeryNon-invasive stereotactic radiosurgery

Diagnosis and TreatmentDiagnosis and Treatment

Diagnosis: Benign Brain TumorDiagnosis: Benign Brain Tumor Treatment:?Treatment:?

Chemo/Immuno therapy Chemo/Immuno therapy Blood Brain Blood Brain BarrierBarrier

Invasive brain surgery Invasive brain surgery High Risk High Risk Non-invasive radiotherapy Non-invasive radiotherapy Too Non- Too Non-

SpecificSpecific Non-invasive stereotactic radiosurgeryNon-invasive stereotactic radiosurgery

What is Stereotactic What is Stereotactic Radiosurgery?Radiosurgery?

Method to non-invasively & Method to non-invasively & specifically treat benign/malignant specifically treat benign/malignant tumors and tissue abnormalitiestumors and tissue abnormalities Uses methods of stereotactic 3-D Uses methods of stereotactic 3-D

localization of surgical sitelocalization of surgical site Uses radiosurgical techniques to Uses radiosurgical techniques to

perform the “surgery”perform the “surgery”

3-D Stereotactic 3-D Stereotactic LocalizationLocalization

Goal: To target the tissue of interest with as much accuracy Goal: To target the tissue of interest with as much accuracy as possibleas possible

Use imaging and 3-D mapping techniques to target tissue Use imaging and 3-D mapping techniques to target tissue of interestof interest 4 general medical imaging modalities used:4 general medical imaging modalities used:

X-RayX-Ray PET PET MRIMRI Digital Subtracted AngiographyDigital Subtracted Angiography

Use the patient as a reference for the localizationUse the patient as a reference for the localization 2 general methods:2 general methods:

Frame stereotactic localization (old school)Frame stereotactic localization (old school) Frameless stereotactic localization (new school)Frameless stereotactic localization (new school)

The Imaging ModalitiesThe Imaging Modalities

Tomographic Techniques:Tomographic Techniques: PET (CT) and MRIPET (CT) and MRI Good for tumor pathologiesGood for tumor pathologies Use multiple layers to get 3-D imageUse multiple layers to get 3-D image

X-ray-based Techniques:X-ray-based Techniques: X-ray and Digital Subtracted AngiographyX-ray and Digital Subtracted Angiography Good for vascular imaging (for treatment of Good for vascular imaging (for treatment of

vascular malformations)vascular malformations) Use pins and depth perception methods to get Use pins and depth perception methods to get

3-D localization3-D localization

Frame TechniquesFrame TechniquesWith tomographic imaging modalities (CT and MRI), use the N-frame as a basis for 3-D visualization:

CT

N-Frame

MRI

Gibson D, et al. Stereotactic Localization in Medical Imaging: A Technical and Methodological Review. Journal of Radiosurgery, Vol 2, No. 3, 1999

Frame Frame TechniquesTechniques

With X-ray imaging modalities:

Schematic

Angiography (X-ray)

Schematic of basis for 3-D imaging

Frameless StereotaxyFrameless Stereotaxy

Implanted Gold Markers

Amorphous silicon detectors (CyberKnife)

Display of treatment planning:

http://virtualtrials.com/jhrs.cfm

RadiosurgeryRadiosurgery

Focused radiation beams delivered to a Focused radiation beams delivered to a specific tissue volume specific tissue volume

Multiple beams or multiple passes Multiple beams or multiple passes (fractionated treatment) that intersect(fractionated treatment) that intersect Keeps radiation exposure to surrounding tissue Keeps radiation exposure to surrounding tissue

at benign levelsat benign levels Treats targeted tissue (the point of intersection) Treats targeted tissue (the point of intersection)

with a higher dose of radiation with a higher dose of radiation

http://neurosurgery.medsch.ucla.edu/programs/radiosurgery/radiosurgery_intro.html

How does it work?How does it work? How is it therapeutic?How is it therapeutic?

Radiation Radiation does notdoes not remove the tumor or tissue remove the tumor or tissue abnormalityabnormality

For tumors, radiation distorts DNA (ionizing For tumors, radiation distorts DNA (ionizing radiation induces mutations and other forms of radiation induces mutations and other forms of DNA damage)DNA damage)

High incidence of DNA damage and ionization induces High incidence of DNA damage and ionization induces cell-cycle arrest (cells stop growing and replicating) and cell-cycle arrest (cells stop growing and replicating) and causes the cell to lose its ability to retain watercauses the cell to lose its ability to retain water

Tumor reduction happens at the rate of the normal Tumor reduction happens at the rate of the normal growth rate of that tumorgrowth rate of that tumor

For arteriovenous malformations (tangle of blood For arteriovenous malformations (tangle of blood vessels), radiation induces the thickening and vessels), radiation induces the thickening and closing off of the blood vesselclosing off of the blood vessel

How does it work?How does it work?

Benign tumors take up to 2 years to Benign tumors take up to 2 years to disappeardisappear

Metastatic (Cancerous) tumors (with Metastatic (Cancerous) tumors (with a much faster growth rate) take only a much faster growth rate) take only months to disappearmonths to disappear

Side EffectsSide Effects Swelling:Swelling: cells lose ability to retain cells lose ability to retain

fluid, edema may occurfluid, edema may occur Necrosis:Necrosis: dead tumor cells may cause dead tumor cells may cause

complications (inflammation, fibrosis)complications (inflammation, fibrosis) Psychological side effects:Psychological side effects: loss of loss of

memory, decreased cognitive abilities, memory, decreased cognitive abilities, etc. (you are taking out a chunk of etc. (you are taking out a chunk of brain!)brain!)

Radiation-induced tumor/cancer:Radiation-induced tumor/cancer: radiation-induced mutations may result radiation-induced mutations may result in a new tumor or cancerin a new tumor or cancer

ApplicationsApplications Mostly used for brain surgery Mostly used for brain surgery

It’s where other more invasive procedures are It’s where other more invasive procedures are deemed too riskydeemed too risky

Machines are designed mostly for brain surgeriesMachines are designed mostly for brain surgeries Frame stereotaxy only allows for brain surgeryFrame stereotaxy only allows for brain surgery But new machines and stereotaxy techniques But new machines and stereotaxy techniques

are allowing for application in other parts of the are allowing for application in other parts of the bodybody

Mostly used for tumors and vascular Mostly used for tumors and vascular malformationsmalformations But new therapeutic applications have been But new therapeutic applications have been

developed for other tissue diseases and developed for other tissue diseases and functional disordersfunctional disorders

Types of RadiationTypes of Radiation Differs with different machines:Differs with different machines:

High-energy X-ray High-energy X-ray From linear accelerator systemsFrom linear accelerator systems

Gamma radationGamma radation From Cobalt-60 sourceFrom Cobalt-60 source

ProtonProton From particle beam or cyclotronFrom particle beam or cyclotron Limited use in the USLimited use in the US Uses Bragg Peak principle:Uses Bragg Peak principle:

As proton slows down, it gives off disproportionately As proton slows down, it gives off disproportionately more energymore energy

Right before it stops, it gives off most of its energy, Right before it stops, it gives off most of its energy, resulting in a peak at that depth of tissueresulting in a peak at that depth of tissue

Different Machines in UseDifferent Machines in Use

Gamma KnifeGamma Knife Gamma radiation from Cobalt-60 SourceGamma radiation from Cobalt-60 Source Use multiple beams to treat tissue volumeUse multiple beams to treat tissue volume

LINAC-based systems (X-Knife)LINAC-based systems (X-Knife) High-energy X-ray from Linear Accelerator deviceHigh-energy X-ray from Linear Accelerator device Use fractionationUse fractionation

CyberKnifeCyberKnife Also a LINAC system, but LINAC is on a robotic armAlso a LINAC system, but LINAC is on a robotic arm Use fractionationUse fractionation Can be used for parts of body other than the headCan be used for parts of body other than the head

Gamma KnifeGamma Knife

-Over 30 years of clinical use and a great deal of publications

-Targeting Precision of within 2mm

-Multiple targets can be easily treated in one session

http://www.elekta.com/ContentUS.nsf

LINAC-Based SystemsLINAC-Based Systems

-Less accurate

-In use in more hospitals

-Less efficient (longer treatment times)

http://www.radionics.com/resources/patient/xknife_description.shtml

CyberKnifeCyberKnife

-Can treat most regions of body

-w/ Stereotactic frame, can approach accuracy of LINAC or GammaKnife

-Real-time frameless stereotaxy can be used

Questions?Questions?