Correction of iodine-123-labeled meta-iodobenzylguanidine uptake with multi-window methods for standardization of the heart-to-mediastinum ratio.
BACKGROUND
To overcome differences in the choice of collimator for an iodine-123 ((123)I)-labeled meta-iodobenzylguanidine (MIBG) heart-to-mediastinum (H/M) ratio, we examined multi-window correction methods with (123)I dual-window (IDW) and triple-energy window (TEW) acquisition.


RESULTS
Standard phantoms, which consisted of the heart, mediastinum, lung, and liver, were generated. Three correction methods were compared: TEW and two IDW methods (IDW(0) and IDW(1)). Low-energy high-resolution (LEHR), medium-energy (ME), and (123)I-specific low-medium-energy high-resolution (LMEHR) collimators were used. Clinical studies were performed in 10 patients. In the phantom study, the H/M ratio was significantly underestimated without correction, with both the LEHR and ME collimators (70% and 88% of the true value). When H/M with the LEHR collimator was divided by uncorrected H/M with the ME collimator, the ratio (mean +/- SD) was 80% +/- 5%, 98% +/- 5%, 104% +/- 7%, and 98% +/- 5% for the no-correction, TEW, IDW(0), and IDW(1) methods, respectively. Clinical studies with the LEHR collimator after TEW and IDW correction (uncorrected average H/M ratio, 1.86 +/- 0.23; TEW, 2.47 +/- 0.46, P = .0015; IDW, 2.46 +/- 0.46, P = .0017) provided comparable values to the uncorrected ME collimator (2.56 +/- 0.46, P = NS vs TEW and IDW).


CONCLUSIONS
The H/M ratio with the ME collimator, after application of the TEW or IDW methods, was close to the theoretical value in the phantom study. However, the corrected H/M ratios with the LEHR collimator provided comparable H/M ratios to the uncorrected ME data in phantom and clinical studies.
Nakajima
Kenichi
K
Department of Biotracer Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan. nakajima@med.kanazawa-u.ac.jp
Matsubara
Kosuke
K
Ishikawa
Takehiro
T
Motomura
Nobutoku
N
Maeda
Ryo
R
Akhter
Nasima
N
Okuda
Koichi
K
Taki
Junichi
J
Kinuya
Seigo
S
D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D016477:Artifacts; D002138:Calibration; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008482:Mediastinum / Q000000981:diagnostic imaging; D009206:Myocardium / Q000378:metabolism*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine