Background/Aim. Currently used radiopharmaceuticals are nonspecific and most
of them are accumulated by benign tumors as well as inflammatory lesions,
abscess or granulomatous lesions. Some factors such as the choice of
radiopharmaceutical applied, histopathologic type of tumor, its size,
location or previous tumor treatment could influence tumor imaging
sensitivity. The aim of this study was to investigate accumulation of
99mTc-methoxy-2-isobutylisonitrile (99mTc- MIBI) by counting early/delayed
uptake and release of this radiopharmaceutical inside lung tumors and
evaluating possible factors which could be involved in its accumulation.
Methods. Two-phase 99mTc-methoxy-2-isobutylisonitrile single photon emission
computed tomography scan (early and delayed scan) was performed in 60
patients with lung tumors (the group 1 - 30 benign, and the group 2 - 30
malignant tumors). We calculated the uptake ratio on early (early ratio -
ER), delayed images (delayed ratio - DR) and retention index (RI). Individual
influence of etiology, diameter, localization, and histological type on
uptake/release values was evaluated with regression analysis. Results. The
values of ER and DR were significantly different in both groups (p < 0.01),
showing lower values in benign vs malignant lung tumors (ER 1.36 ? 0.094 and
DR 1.25 ? 0.089 vs ER = 1.93 ? 0.106 and DR = 1.7 ? 0.095 respectively).
Tumor size showed a significant influence on the change of ER and DR values
(p < 0.01), with greater uptake in tumors > 3 cm. RI values showed no
significance between the two groups (p > 0.05). Conclusion. The uptake ratio
of 99mTc-methoxy-2-isobutylisonitrile could be a useful index in
differentiating lung tumors, while RI has no influence on this. Among the
evaluated factors, ER and DR values are significantly influenced only by the
diameter of lung tumor, while localization or different histological types
between the groups has no influence on this.
Photon emission and atomic collision processes in two-phase argon doped with xenon and nitrogen