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Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
Hsc 340 9 16
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Hsc 340 9 16

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Transcript

  • 1. HSC 340 9 9-16-10
    • Conventional Simulation procedures
    • Computed Tomography Simulation procedures
  • 2. Radiation Therapy process
    • Not all patients will need all steps, nor will they always occur in sequence
  • 3. Diagnosis
    • Screening
    • Cancer Imaging
    • Pathology
    • Staging
  • 4. Therapeutic Decisions
    • Cure
    • Palliation
    • Benign
    • Surgery-radiation-chemotherapy
    • Patient Interview
  • 5. Simulation
    • Fluoroscopy based
    • CT simulation
    • Patient positioning
    • Immobilization devices
    • DRRs
  • 6. Treatment Planning
    • Identifying PTV
    • Identifying critical structures
    • Selection of treatment technique
    • Isodose distribution
    • Calculation of treatment beams
    • Optimization
  • 7. Treatment
    • Treatment verification & imaging
    • Dosimetry checks
    • Treatment delivery and monitoring
    • Patient assessment
    • Record keeping
  • 8. Patient follow-up
    • Patient assessment
    • Normal tissue response
    • Tumor control
  • 9. Conventional Simulation Procedures
    • Synonymous with fluoroscopy-based simulation
    • Nomenclature
      • Localization
      • Verification
      • Radiopaque marker
      • Contrast media
      • Seperation
      • Field Size
  • 10. ICRU Reports
  • 11.
    • GTV- gross tumor volume
    • CTV- clinical tumor volume
    • ITV- Internal target volume
    • PTV- planning target volume
    • TV- treated volume
    • IV- Irradiated volume
    • OAR- Organs at risk
  • 12. Acronyms pg. 446 image
    • CAX
    • IFD
    • ISO
    • SAD
    • SFD
    • SSD
    • TT
  • 13. Body Planes Sagittal- L and R Coronal- Ant and Post Transverse- Inf and Sup
  • 14.  
  • 15. Localization Methods
    • SAD and SSD
    • SSD method
      • Requires repositioning the patient for each field before treatment
      • ODI reading on skin will always be 100cm
    • SAD method
      • aka: isocentric technique
      • ODI reading on skin will vary according to thickness or seperation of the patient, also depending on the depth of the tumor from the skin
    • Both define the field size at 100cm, only difference is where that distance is located (on skin or within patient)
  • 16. Contrast Media
    • Used to visually enhance structures
    • Positive- Barium, iodinated contrast
    • Negative- air
    • Careful workup
  • 17. Procedure
    • *****Must be well documented*****
    • Presim planning
    • Room preparation
    • Explanation (Consent?)
    • Patient positioning
    • Immobilization
    • Setting parameters
    • Radiographic exposure
    • Documentation
  • 18. Presim planning
    • Assessment of patient
    • Extent of disease
    • Concerns
    • Therapist-Physician consult
    • Chart thoroughly read
  • 19. Room preparation
    • Usually busy, make the most of it
    • H & N
      • Water bath temp checked
      • Mask ready
      • Headrest chosen (A to F)
      • Stent, bite block, mouthpiece
      • Wires for surgical scar delineation
      • Straps to pull shoulders down
  • 20.
    • Thorax
      • Headrest
      • Vac-lok
      • Wingboard
      • BBs, wire
    • Pelvis
      • Alpha cradle
      • T-bar with strap
      • Headrest
      • Ring for hands to hold
      • Contrast agents
      • Catheter
  • 21. Explanation
    • Assessment
    • Communication
    • Education
  • 22. Patient Positioning
    • If they are not comfortable, then not effective
    • If it is not reproducible then it may cause a geographic miss or irradiation of critical structures
    • Supine or Prone
    • Emergencies may lead to semi-sitting position
  • 23. Patient Immobilization
    • Effective immobilization devices restrict a patient from moving
    • Can range from simple to complex
      • Tape
      • Rubberbands
      • Alpha cradle YouTube - Alpha Cradle Mold Maker Instruction
      • Vac-lok YouTube - SecureVac Vacuum Cushions from Bionix
      • Head mask
  • 24. Setting Parameters
    • Field parameters:
      • Width, length, gantry angle, collimator angle, position of isocenter
  • 25. Radiographic Exposure
    • Radiographic images taken in sim are referred to as “masters”
    • kVp, mA, time and distance
    • Note patients body type and condition
    • Source to film distance recorded to show mag factor
  • 26. Documentation
    • This is a medical record
    • Accuracy is key
    • Involves both patient and chart
    • Tattoos
    • Landmarks
  • 27. Contouring
    • Contour is a reproduction of external body shape
    • Solder wire, thermoplastic tube, plaster strip
    • Must be accurate!!
  • 28. Shifts YouTube - RT Quick Clip - Patient Shifts
  • 29. CT Simulation Procedures Hounsfield Units- attenuation rates displayed as pixels of different shades of gray. Correspond to different e- densities -1000 Air 0 water 1000 dense bone Figure 23-8 X-ray tube---collimation---360 rotation---transmission measurements recorded by detectors
  • 30.
    • Conventional CT- slice by slice, one image, table moves
    • Helical/spiral CT- volume, table moves while scanning
  • 31. Major steps in CT Simulation
    • Presim planning
    • Room preparation
    • Explanation of procedure
    • Patient positioning and immobilization
    • CT data acquisition
    • Target and normal tissue localization
    • Virtual sim of treatment fields
    • Generation of dose distribution
    • Documentation
  • 32. Benefits of CT Simulation
    • Outline and view critical structures
    • Optimal beam placement
    • Cone down or boost can be done w/o patient
    • BEV capability
    • Electronic field shaping
  • 33. Contrast
    • Intravascular
    • Oral
    • Intrathecal
    • Intraarticular
    • Must get medical history first
  • 34. IV Contrast agents & site specificities
    • H & N- injected seconds before scan
      • Highlights vessels and distinguish from LN
    • Liver- scan needs to be started 20 to 90 sec after injection
      • Visualize blood supply from portal vein and hepatic artery
    • Pelvis- IV contrast 15 minutes after injection
      • Bladder
    • Brain- 10 to 30 minutes prior to scan
      • Highlight tumor due to vasculature
  • 35. Other contrast agents and the specificities
    • GI tumors- barium paste 30 min prior for small bowel
    • Rectal marker, vaginal marker, radiopaque catheters….
    • ***High contrast materials may alter dose calcs***
  • 36. Reactions to contrast
    • Mild
    • Moderate
    • Severe
  • 37. Room preparation
    • Same as conventional, be aware of bore size and patient positioning
    • Flat table top if regular couch is curved
  • 38. CT Artifacts
    • Unwanted image abnormalities that can be caused by patient motion, anatomy, design of scanner, or system failure
    • Beam hardening
    • Partial volume effect
    • Star artifact
    • Ring artifact
    • Motion and helical artifact
  • 39. Fusion/Registration
    • Starts with 2 sets of images
    • Locate similar image features (landmarks)
    • Manually move one image on top of another
  • 40. Respiratory Gating
    • Used to have patients hold breath
    • Now we track the patients range of motion while breathing

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