Bone lesion detection with carrier-added 99mTc-EDTMP in comparison with 99mTc-DPD.

An increased uptake of bone-seeking radiopharmaceuticals into malignant bone lesions could further improve the diagnostic accuracy of routine bone scanning. The tracers used in clinical routine for bone scanning are methylene-diphosphonate (MDP), dicarboxypropane-diphosphonate (DPD) and ethylenediaminetetramethylene-phosphonate (EDTMP). MDP and DPD are usually labelled with 99mTc for diagnostic use, whereas EDTMP is labelled with 153Sm for therapeutic purposes. This study aimed to compare, for the first time, bone scanning with an improved preparation of 99mTc-EDTMP (by the addition of rhenium) (carrier-added) with 99mTc-DPD. Twenty malignant bone lesions were investigated in 10 patients. The ratios of bone lesion to soft tissue (BL/ST) and of bone lesion to normal bone (BL/NB) were compared 3 h after the injection of either compound. Quantitative analysis demonstrated a significant (P<0.05) difference in BL/ST ratio in favour of 99mTc-DPD. The BL/NB ratio was not significantly different. Visual image analysis resulted in a clinically comparable interpretation of imaging studies with the use of 99mTc-DPD and carrier-added 99mTc-EDTMP. These preliminary data support the concept of carrier addition to increase bone uptake by the modification of the complex structure of 99mTc-EDTMP. However, any advantage over conventional 99mTc-based tracers for bone scintigraphy in clinical use needs to be demonstrated in controlled trials.

Scintigraphic imaging of the adrenal glands.

This article presents the well established scintigraphic imaging techniques of the adrenal glands. Both adrenocortical scintigraphy with [131]6beta-iodomethylnorcholesterol (NP-59) and adrenomedullary imaging with 131I or 123I-labelled metaiodobenzylguanidine (MIBG) as function-dependant imaging techniques provide functional metabolic information for lesion characterization. They enable the distinction between unilateral and bilateral adrenal lesions. Furthermore, they have the advantage of giving the possibility of a whole body evaluation with a single administration of the tracer without additional radiation dose. On the other hand, radiological imaging modalities provide excellent anatomical details which is essential for planning therapy. Both radiological and scintigraphic imaging methods of the adrenal glands are necessary and should, therefore, be considered complementary.