Pentlow K S, Graham M C, Lambrecht R M, Daghighian F, Bacharach S L, Bendriem B, Finn R D, Jordan K, Kalaigian H, Karp J S, Robeson W R, Larson S M
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
J Nucl Med. 1996 Sep;37(9):1557-62.
PET is potentially very useful for the accurate in vivo quantitation of time-varying biological distributions of radiolabeled antibodies over several days. The short half-lives of most commonly used positron-emitting nuclides make them unsuitable for this purpose. Iodine-124 is a positron emitter with a half-life of 4.2 days and appropriate chemical properties. It has not been widely used because of a complex decay scheme including several high energy gamma rays. However, measurements made under realistic conditions on several different PET scanners have shown that satisfactory imaging and quantitation can be achieved.
Whole-body and head-optimized scanners with different detectors (discrete BGO, block BGO and BaF2 time-of-flight), different septa and different correction schemes were used. Measurements of resolution, quantitative linearity and the ability to quantitatively image spheres of different sizes and activities in different background activities were made using phantoms.
Compared with conventional PET nuclides, resolution and quantitation were only slightly degraded. Sphere detectability was also only slightly worse if imaging time was increased to compensate for the lower positron abundance.
Quantitative imaging with 124I appears to be possible under realistic conditions with various PET scanners.
正电子发射断层扫描（PET）对于在数天内对放射性标记抗体的随时间变化的生物分布进行准确的体内定量可能非常有用。大多数常用正电子发射核素的半衰期较短，使其不适用于此目的。碘 - 124是一种半衰期为4.2天且具有合适化学性质的正电子发射体。由于其复杂的衰变方案，包括几种高能伽马射线，它尚未得到广泛应用。然而，在几种不同的PET扫描仪上在实际条件下进行的测量表明，可以实现令人满意的成像和定量。
使用具有不同探测器（离散BGO、块状BGO和BaF2飞行时间探测器）、不同隔板和不同校正方案的全身和头部优化扫描仪。使用体模对分辨率、定量线性以及在不同背景活动中对不同大小和活度的球体进行定量成像的能力进行测量。
与传统PET核素相比，分辨率和定量仅略有下降。如果增加成像时间以补偿较低的正电子丰度，球体可检测性也仅略差。
在实际条件下，使用各种PET扫描仪进行124I定量成像似乎是可行的。
