Assessment of 99Tcm-tetrofosmin lung uptake: a modified method to avoid the contribution from high chest wall activity.
Evaluation of lung uptake during routine 99Tcm-tetrofosmin myocardial SPET (single photon emission tomography) studies may be hindered by substantial chest muscle uptake, particularly post-exercise. This study investigated this proposal and analysed the various components of chest activity that may add to the real lung uptake. Exercise SPET studies were performed on normal subjects using 99Tcm-tetrofosmin and compared with the results of 99Tcm-sestamibi and 201Tl studies. The chest to heart count ratio (CHR) was calculated from the anterior SPET projection and further subclassified into lung, anterior chest and posterior chest to heart ratios (LHR, AHR, PHR) from the left anterior oblique (LAO) projection. On post-exercise images, the 99Tcm-tetrofosmin CHR was significantly higher than that of 201Tl and 99Tcm-sestamibi. Both the 99Tcm-tetrofosmin AHR and PHR were higher than those of 201Tl and 99Tcm-sestamibi. However, the LHR was similar for all three radiopharmaceuticals. In contrast, the rest 99Tcm-tetrofosmin images differed little from the 201Tl and 99Tcm-sestamibi ones. Thus, 99Tcm-tetrofosmin lung uptake post-exercise should be interpreted with caution, as chest muscle uptake is higher than normal. A more accurate evaluation of 99Tcm-tetrofosmin lung uptake is achieved from the LAO projection, where the contribution from chest muscle counts is much less than in the routinely used anterior projection.
Heiba
S I
SI
Department of Nuclear Medicine, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait.
Ziada
G
G
Higazy
E
E
Saleh
M
M
Elgazzar
A H
AH
D000328:Adult; D001692:Biological Transport; D001794:Blood Pressure; D005080:Exercise Test; D006321:Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics*; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012016:Reference Values; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi