PET Cyclotrons

1
PET Cyclotrons

• Bill Alvord
• CTI Cyclotron Systems

2
The PET process
PETNET
CCS
Distribution
18O water
Cyclotron
Chemistry
18FFDG
CPS, CDM, ACT, Mirada
Service
Information services
Physician/ Patient
Scanners
3
PET Isotope Logistics

• Decay
• Each radioisotope has a unique half-life.
• The four commonly used isotopes in PET and their
  half lives are

4
PET Isotope Logistics

• Decay - review
• There is a fixed probability of decay for each
  nucleus resulting in exponential decay.
• The time it takes for the decay rate to drop to
  half its value is called the half-life
• The decay rate at a given period of time can be
  calculated by

• where
• A0 decay rate at t 0
• t1/2 half life (in same units as t)
• t time since A0 was measured (same units as
  t1/2)

5
PET Isotope Logistics
6
PET Isotope Logistics

• Activation
• Stable nuclei can be bombarded with nucleons
  (neutrons or protons) or other nuclei to form
  activated nuclei
• This process is referred to as a nuclear reaction
• The nomenclature for nuclear reactions is
• target nucleus(bombarding particle, recoiling
  particle)product nucleus
• For example
• 18O(p,n)18F
• means 18O bombarded by protons
• results in 18F and a neutron

7
PET Isotope Logistics

• Production
• As a nuclear reaction takes place, the population
  of activated nuclei grows, as does the decay rate
• At some point the decay rate and activation rate
  are equal
• The activity at this point is saturated. The
  saturation activity is an indication of the
  production rate. Knowing the saturation activity
  one can calculate the expected activity at any
  time using the following equation

8
PET Isotope Logistics

• Production curve
• Saturation activity is an indication of
  production rate
• Production rate is proportional to current

9
PET Isotope Logistics

• Yield curve
• Saturation activity is an indication of
  production rate
• Production rate is proportional to current
• Production rate is dependent on energy

10
Corporate structure
CTI, Inc.
CTI PET Systems, Inc.
CTI Cyclotron Systems
CTI Services
PETNet, Inc.
ACT, Inc. CDM
RDS RD RDS Production
ECAT RD Production ECAT Product Support
Siemens, CTI, Hitachi are distr. of CPS
products

• Radioactive Sources
• RDS and US ECAT Service
• Marketing Sales

BGO Crystal Production LSO Detector Material
RD LSO Detector Material Production

• PETNet PMDCs
• Nuclear
• Pharmacies
• LA Tech Center

11
CTI The Power Behind PET
12
The cyclotron as seen by...
13
The first cyclotron E.O. Lawrence - 1932
14
Cyclotron components
Dee stem
Dee
Ion source
Hill
Valley
15
Cyclic particle acceleration

• Magnetic field (Lorentz) force
• No good for accelerating by itself
• Can curve charged particle orbits

16
Target port
Beam extractor
Ion source
Straight orbit in valleys (low magnetic field)
Curved orbit on hills (high magnetic field)
Hills
17
Fully Upgradeable Product Family

• eclipse HP
• High Production system
• Up to 8 Targets

• eclipse RD
• Research system
• Up to 16 Targets

• eclipse ST
• Entry level system
• Up to 8 Targets

UPGRADE PATH
18
CCS Production
19
Standard Products
Shielded Cyclotrons 16 Target Locations Upgrade
paths Largest Installed Base
20
Eclipse RD
Retractable Shields
Cyclotron - 22,000 pounds Shields - 60,000
pounds Cabinets - 3,200 pounds Total 85,200
pounds
1 Power Supply Cabinet 1 Control Cabinet 1 Water
System Cabinet
21
Space Constraints

• 22 ft w x 23ft d x 10 ft h room for cyclotron and
  all utilities
• 1.5 mR/Hr shielding available
• No bunker, no separate control room
• Flexible remote operation capabilities

CTI System
Comparable Systems
22
Four Dee Accelerator Design

• Four Dees Provide More Periods of Acceleration
  per Orbit
• particles spend less time in accelerator
• reduced internal activation
• Top-mounted Components
• easier service
• improved alignment

23
Single Port / Multi-Position Targets

• Integrated Target Support
• Shared utilities minimize leaks and reduce
  complexity
• Target Umbilicals
• Targets can be installed or removed with one
  screw
• Target change requires no intervention in vacuum
• Design minimizes personnel exposure time

24
CTI Cyclotron product features

• Lowest Power-In / Highest Product Out
• Lowest Radiation Fields in the Industry
• Greatest Flexibility 16 Targets with 64
  combinations
• Highest Gas Specific Activity (5X to 10X higher)
• Only Available Remote Control Capabilities
• Largest Installed Base and Service Organization

25
Cyclotron Room

• PETNet Dallas

26
Chemistry Lab

• PETNet Dallas

27
Phase plot
28
PET Isotope Targets - Design
Target elements
29
PET Isotope Targets - Design

• Design constraints
• Temperature
• Pressure
• Medium and phase (liquid water or hot gas)
• Chemistry
• Volume
• Lifetime
• Energy/yield

30
PET Isotope Targets - Design

• Support equipment
• Small volumes, high pressures and low
  contamination
• Much of the equipment comes from HPLC
• Capillary tubing
• Chromatography valves (up to 1000 psig)
• Pressure transducers
• Syringe pumps
• Diaphragm pumps
• HPLC pumps

31
PET Isotope Targets - Systems
Isotope 18F Reaction 18O(p,n)18F Chemical form
Fluoride ion (F-) Target material 18O enriched
water (argon overpressure) Target volume 1.1
ml Target body 99.99 pure silver Target window
.001 thick Havar (high strength Nickel-Cobalt
alloy) Typical pressure 650 psig beam off, 800
psig beam on
32
PET Isotope Targets - Systems
Isotope 18F Reaction 18O(p,n)18F Chemical form
Fluorine gas (F2) Target material 18O enriched
gas (Ar/5 F2 second shoot) Target volume 7 ml
(120 std. cc gas) Target body Aluminum Target
window .001 thick Havar (high strength
Nickel-Cobalt alloy) Typical pressure 280 psig
beam off, 900 psig beam on
33
PET Isotope Targets - Systems
Isotope 13N Reaction 16O(p,a)13N Chemical form
Ammonium ion (NH4) in water Target material 5
mMol Ethanol in HPLC water Target volume 2
ml Target body Aluminum Target window .001
thick Titanium Typical pressure 320 psig
34
PET Isotope Targets - Systems
Isotope 15O Reaction 15N(p,n)15O Chemical form
Oxygen gas (O2) in Nitrogen gas (N2) Target
material 15N enriched Nitrogen gas with 2.5 O2
Target volume 7 ml (120 std. cc) Target body
Aluminum Target window .001 thick Havar (high
strength Nickel-Cobalt alloy) Typical pressure
280 psig beam off, 900 psig beam on
35
PET Isotope Targets - Systems
Isotope 11C Reaction 14N(p,a)11C Chemical form
Carbon dioxide gas (CO2) in Nitrogen gas
(N2) Target material unenriched Nitrogen gas
with 2.5 O2 Target volume 7 ml (120 std.
cc) Target body Aluminum Target window .001
thick Havar (high strength Nickel-Cobalt
alloy) Typical pressure 280 psig beam off, 900
psig beam on
36
Computational fluid dynamics and water targets

• Problem Dissipate 1000 W in an 800 µl volume
  lose less than 5 of that volume to evaporation
  over 2 hours of irradiation
• Irradiation chamber is pressurized to 650 psig
  with Argon (raises the boiling point of the water
  to 240 C).
• CFD helps determine the appropriate shape and
  surface area of the enclosure

37
Pet tracer logistics summary

• Small is Beautiful.
• Why make more neutrons than you need?
• Distance is the enemy.
• We are shipping ice cream cones.
• More is better.
• Replication is the key.