Bone trauma and related benign disease: assessment by bone scanning.

The radionuclide investigation of skeletal trauma in the past was confined generally to scintimetry and an occasional bone scan. The development of improved radiopharmaceuticals, including 99mTc-labeled compounds with their enhanced sensitivity, and the refinement of imaging devices offering superior resolution and speed have allowed a more detailed assessment of conditions resulting from trauma. Practical approaches to the diagnosis of subtle bone injury resulting in stress fracture, the differentiation between delayed healing and nonunion, and early recognition of avascular necrosis and osteomyelitis are now available. The changing pattern of radionuclide uptake in bone following damage by radiation and other abnormalities as a consequence of trauma also can be easily studied.

Chromatographic, mass spectral, and visible light absorption characteristics of toluidine blue O and related dyes..

Contrary to earlier literature reports, the impurities in toluidine blue O were shown by column chromatography, TLC, and mass spectrometry to be N-methyl homologs of 2-methylthionine rather than N-methyl homologs of thionine. Small amounts of 2-methyl-3-amino-7-methylaminophenothiazine and 2-methyl-3,7-diaminophenothiazine were identified in commercial samples of toluidine blue O. However, sample handling and a warm alkaline environment can cause rapid demethylation of the dye.

Comparison of 85Sr, 87mSr, 18F, and 99mTc-labeled phosphates for bone scanning.

The observation by Subramanian and his co-workers that a 99mTc-labeled polyphosphate had excellent affinity for bone has led to widespread use of 99mTc-labeled phosphates as bone scanning agents. Initially, only polyphosphate was employed, but because of somewhat inconstant results and difficulty in preparation of this product, other phosphate compounds were sought. We soon discovered that an inorganic compound, pyrophosphate, appeared to have certain advantages over polyphosphate. Other workers formulated diphosphonates (organic phosphates) which also demonstrated advantages over polyphosphates. Comparison studies in rabbits utilizing 85Sr, 87mSr, 18F, and several phosphates (inorganic and organic) proved the 99mTc-labeled phosphates to be clearly superior in delineating normal skeletal anatomy. Studies in humans confirmed that excellent visualization of bone was obtained with 99mTc-labeled phosphates using either a gamma camera or a rectilinear scanner. What was not known, however, was just how reliable this class of agents would prove to be in detecting bone disease when compared to bone-seeking radiopharmaceuticals such as 85Sr, 87mSr, and 18F. Further comparative analyses have clearly demonstrated that both inorganic and organic 99mTc phosphate complexes are extremely sensitive in revealing more bone disease than the older bone scanning agents.