Development and validation of a patient-tailored dose regime in myocardial perfusion imaging using conventional SPECT.
BACKGROUND
The decreasing image quality in heavier patients can be compensated by administration of a patient-specific dose in myocardial perfusion imaging (MPI) using a cadmium zinc telluride-based SPECT camera. Our aim was to determine if the same can be achieved when using a conventional SPECT camera.


METHODS
148 patients underwent SPECT stress MPI using a fixed Tc-99m tetrofosmin tracer dose. Measured photon counts were normalized to administered tracer dose and scan time and were correlated with body weight, body mass index, and mass per length to find the best predicting parameter. From these data, a protocol to provide constant image quality was derived, and subsequently validated in 125 new patients.


RESULTS
Body weight was found to be the best predicting parameter for image quality and was used to derive a new dose formula; A admin (MBq) = 223·body weight (kg)(0.65)/T scan (min). The measured photon counts decreased in heavier patients when using a fixed dose (P < .01) but this was no longer observed after applying a body-weight-dependent protocol (P = .20).


CONCLUSIONS
Application of a patient-specific protocol resulted in an image quality less depending on patient's weight. The results are most likely independent of the type of SPECT camera used, and, hence, adoption of patient-specific dose and scan time protocols is recommended.
Department of Nuclear Medicine, Isala Hospital, PO Box 10400, Zwolle, 8000 GK, The Netherlands. jorisvdijk@gmail.com.|MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands. jorisvdijk@gmail.com.
J D
JD
van Dijk
Department of Nuclear Medicine, Isala Hospital, PO Box 10400, Zwolle, 8000 GK, The Netherlands. p.l.jager@isala.nl.
P L
PL
Jager
Department of Cardiology, Isala Hospital, Zwolle, The Netherlands. j.ottervanger@diagram-zwolle.nl.
J P
JP
Ottervanger
Department of Nuclear Medicine, Isala Hospital, PO Box 10400, Zwolle, 8000 GK, The Netherlands. j.boer@isala.nl.
J
J
de Boer
Department of Nuclear Medicine, Isala Hospital, PO Box 10400, Zwolle, 8000 GK, The Netherlands. a.h.j.oostdijk@isala.nl.
A H J
AH
Oostdijk
Department of Cardiology, Isala Hospital, Zwolle, The Netherlands. e.engbers@isala.nl.
E M
EM
Engbers
MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands. c.h.slump@utwente.nl.
C H
CH
Slump
Department of Nuclear Medicine, Isala Hospital, PO Box 10400, Zwolle, 8000 GK, The Netherlands. s.knollema@isala.nl.
S
S
Knollema
Department of Medical Physics, Isala Hospital, Zwolle, The Netherlands. j.a.van.dalen@isala.nl.
J A
JA
van Dalen
D000368:Aged; D001835:Body Weight; D003287:Contrast Media / Q000008:administration & dosage; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004334:Drug Administration Schedule; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D015902:Gamma Cameras; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000295:instrumentation* / Q000379:methods; D009943:Organophosphorus Compounds / Q000008:administration & dosage*; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D018802:Patient-Centered Care / Q000379:methods; D066230:Patient-Specific Modeling; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation* / Q000379:methods
D003287:Contrast Media; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin
SPECT; activity; dose; myocardial perfusion imaging