Transcript rubidium-82

STUDY OF THE MYOCARDIAL
PERFUSION BY RUBIDIUM-82 PET-CT:
QUALITY CONTROL
F. El Hakmaoui1, G.Allenbach1, M. Recordon1, J. Malterre1, M. Pappon1,
M. Kosinski2, F. Camus1,2, A. Boubaker1, J. O. Prior1, V. Dunet1.
1
Département de Médecine Nucléaire, Centre Hospitalier Universitaire Vaudois et Université de Lausanne, Suisse .
2
Institut de Radiophysique. Centre Hospitalier Universitaire Vaudois et Université de Lausanne, Suisse.
INTRODUCTION
 Myocardial perfusion can be studied using SPECT or PET
tracers
PET imaging is limited by the access to tracer production
unit (cyclotron)
Rubidium-82 can easily be produced by a Strontium-82
generator, without the need of cyclotron
 Rubidium-82 is extensively used in USA for myocardial
perfusion imaging by PET-CT
b+
g 511 keV
e-
g 511 keV
ANNIHILATION =
2 Υ’ traveling in
opposite directions
RUBIDIUM-82
 Rb-82 is an analog of K+ (potassium).
 Strontium-82 ( half-life 25.5 days) decays to Rubidium-82 (halflife 75 sec, positron emission, annihilation photons 511kev).
 As Thallium (Tl-201) Rb-82 is extracted by myocardial tissue via
the Na⁺K+-ATPase active transport.
 The short half-life of Rubidium-82 allows to perform rest/stress
imaging within 20 minutes.
 We use an adenosine stress (140 µg/kg/min over 6 min) to
perform real time stress imaging owing to the short half-life of
Rb-82 .
RUBIDIUM-82 GENERATOR
RUBIDIUM-82 GENERATOR
 New generator every month.
 Possible elution every 10min.
 The radionucleidic purity of Rb-82 eluate is
determined by measuring the residual activity of Sr82 and Sr-85 using a ionization chamber.
 Any other radionucleidic in the elution is considered
a radionucleidic impurity .
 The final eluate should not contain more than 0.02
kBq of Sr-82 and not more than 0.2 kBq of Sr-85 per
MBq of Rb-82 injection.
RUBIDIUM-82 INJECTION SYSTEM
 Automatical System
Allow accurate measurement with minimal operator interface
PERFUSION PET IMAGING
Shorter acquisition time
Lower radiation exposure
Attenuation correction
Myocardial blood flow quantification
Ejection Fraction at peak stress
RUBIDIUM-82 PROTOCOLE
140µg/min/kg
Adenosine
(6 min)
C
T
CT
Rest (6 min)
Stress (6 min)
1628 MBq
1628 MBq
t
0’
8’
10’
16’
Normal myocardial
perfusion imaging
Infero-lateral infarct with
residual myocarial
ischemia
AIM OF THE STUDY
 To assess the evolution of Sr-82 and Sr-85
breakthrough during the clinical use of Rb-82
generator .
METHODS
 10 generators Cardiogen-82 ® Bracco Diagnostics
of Rb-82 were used for 481 rest/stress studies.
162 radionucleidic purity controls were performed
before any injection to the first patient.
Sr-82/Rb-82<0.02 kBq/MBq
Sr-85/Rb-82<0.2 kBq/MBq
METHODS
BEFORE ANY INJECTION TO THE FIRST PATIENT
ELUTION 1
Wash out
ELUTION 2
Breakthrough
10’
3’
Rb-82
ACTIVITY
INJECTION TO
PATIENT
1h
Sr-82/Rb-82<0.02 kBq/MBq
Sr-85/Rb-82<0.2 kBq/MBq
Sr-82
ACTIVITY
RESULTS
Sr-82/Rb-82 ratio
Breakthrough Sr-82/Rb-82 (10-3kBq/MBq)
N <20.10-3kBq/MBq
5.00
MEAN
4.00
G2
G3
3.00
G4
2.00
G5
G6
1.00
G7
G8
0.00
G9
2.0
G10
G11
4.0
Eluated volume (L)
6.0
8.0
0.007kbq/MBq (3.5% of the limit)
RESULTS
Sr-85/Rb-82 (10-3 kBq/MBq)
N
Sr-85/Rb-82 ratio
<200.10-3kBq/MBq
Mean
G2
G3
G4
G5
G6
G7
G8
G9
G10
G11
10
9
8
7
6
5
4
3
2
1
0
1 2
3 4
5 6
7
8 9
10 11
12
13
14
15
Days of utilization
0.002±0.0006kBq/MBq (1% of the limit)
16
17
18
19
20
21
22
DISCUSSION
The high peaks may be explained by :
– Intrinsic variations of the activimeter
– Breakthrough variations in the laboratory
– Number of days since last use
(accumulation of Sr-82 during the week-end)
CONCLUSION
 Sr-82 and Sr-85 breakthroughs were small for
a total eluted volume <8L
 Every controls remained under the authorized
limits and allowed the clinical use of Rb-82
THANKS FOR YOUR ATTENTION
Merci de votre attention
Grazie mille per la vostra attenzione
Vielen Dank für Ihre Aufmerksamkeit