Download PET/CT Link Between Radiation Therapy and Planning

PET/CT Link Between
Radiation Therapy and Planning
BY:
JONATHAN BALDWIN, BSRT, CNMT,
RT(CT)
&
GARRETT WINTERS, BSRT, RT(T)
Introduction
— What is Radiation Therapy
— Immobilization Techniques
— What is Radiation Therapy Planning
— PET/CT Equipment Needs For Planning
— PET/CT Protocol Changes
— Drawbacks of PET/CT Planning
What is Radiation Therapy?
What is CT Simulation
— Foundation of radiation therapy
process
¡
¡
Information gathered from the
simulation process determines how the
patient will be treated
Determines patient position
÷
Simulating the daily treatment setup
— Area scanned is determined by
physician
— Images acquired are sent to
dosimetry
How do we reproduce setups?
— Flat Table top
¡ Uncomfortable
¡ Carbon Fiber
¡ Identical to the tx rm tabletop
— Lap Laser system
— Three point setup
1.
Anterior Mark
2.
Lateral Marks
— Immobilization devices
What are immobilization devices?
Why do we need immobilization devices?
— What about internal organ motion?
¡ Respiratory Gating
What happens during the planning process?
— Prescription-Physician
¡ Total dose-Physician
¡ Dosing RestraintsPhysician/Dosimetrist
— Contouring
¡ Treatment volumes-Physician
÷
¡
GTV, CTV, PTV
Normal Tissues-Dosimetrist
— Forward Planning
¡ Algorithm Based
¡ Determines the best beam
arrangement
¡ DVH
Why is simulation so important?
&
What does PET bring to the
table?
Benefits of Planning in PET/CT
— Benefits to Radiation Therapy
¡ Decrease Tumor Margins
¡ Physiologic Information
¡ Treatment Regimen Change
— Benefits to the PET/CT Department
¡ Increased Productivity
¡ Increased Revenue
Benefits of Planning in PET/CT
— Benefits to the Patient
¡
Smaller Treatment Fields
¡
Treatment of Tumors Missed by CT
¡
Increased Effectiveness of Treatment
¡
Treatment Regimen Changes
Accomplishing PET/CT Planning
— PET/CT Technologist must:
¡
Accommodate the Needs of the Radiation Therapy Department
÷
Communication is Key
¡
Thorough Patient Education
¡
Minor Changes to common Protocols
PET/CT Protocol Changes
— General F-18 FDG Protocol
¡ Injection, 60-90 min localization,
PET/CT Scan
— PET/CT Planning Protocol
Changes
PET/CT Protocol Changes
— Localization Time/Coordination
¡ Communicate Injection/Scan Times
¡ Patient Use the Restroom Early
¡ Allow 10-15 Minutes For Proper Set
Up
÷
¡
¡
Multiple Scout Scans Possible
Have Bed/Equipment Prepared
Consistency on Subsequent Studies
PET/CT Protocol Changes
— Positioning Changes
¡ RTX Requires Special Positioning For
Different Pathology
¡ Reproducible Positions
— Contrast Use
¡ Many Pathologies May Require the Use of
Contrast Media
÷
¡
Compensate for Attenuation
IV, Rectal, Bladder, and Esophageal
Contrast
PET/CT Protocol Changes
— Patient Preparation
¡ Explain the Procedure!!
¡ Some Patients will Require Sedative
¡ Remove Immobilization Devices ASAP
— Laser Landmark Adjustments
¡ External Laser System
¡ Adjust Starting Locations Accordingly
Disadvantages To PET/CT Planning
— Cross Departmental Communication
— Time To Complete
— Scanner Bore Size
— Diabetic Patients
Nasopharyngeal Cancer
— Less than 1 case/100,000
— In 2013 2,900 cases in US
— Bimodal age distribution
¡ 15-24 yo
¡ 55-65 yo
— Early stage survival rate
¡ 80%-90%
— Late Stage survival rate
¡ 50%-70%
Adapted from: radiopaedia.org
NSCLC
— Most common type of lung cancer
¡ 224,210 new cases in 2014
¡ 159,260 deaths
— Leading cause of cancer related
death
¡
27%
— Cancer of the elderly
¡ 2/3rd are 65 or older
¡ Avg. age of 70
Adapted from: www.lung.org
Wrap Up
— What is radiation therapy
— What is radiation planning
— What are immobilization devices, and how are they
implemented
— Benefits of PET/CT radiation planning
— Protocol differences with PET/CT planning
— Draw backs to radiation planning PET/CT
Questions