The radionuclide bone scan has been one of the cornerstones of nuclear medicine practice during the past 4 decades. It became clear in the 1960s that strontium-85, with its long physical half-life of 64 days and its very limited administered dose allowance of 100-200 μCu, was superior to plain radiographs for the detection of metastatic bone disease. Because of the high dosimetry, regulatory bodies restricted the use of strontium-85 to suspected malignant disease in adults and proven malignant disease in children. Although promising reports on its non-neoplastic applications were available from outside the United States, that indication was not allowed in the United States.
A major breakthrough in bone imaging occurred in the early 1970s when McAlee and Subramanian introduced technetium-99m (99mTc) polyphosphates as a substitute for strontium-85. During the next decade, several organic and inorganic 99mTc-labeled phosphate carriers were introduced. The development of methylene diphosphonate secured a firm place for bone imaging and became today's worldwide standard. After the introduction of the 99mTc-phosphates, applications of the bone scan to many non-neoplastic processes, principally trauma and infection, proliferated.
Dr Ignac Fogelman has been a frequent contributor to Seminars in Nuclear Medicine. He is certainly world renowned for his numerous articles in the areas of both bone scintigraphy and bone density investigations. We are delighted that both he and his colleague, Dr Gopinath Gnanasegaran, have put together a stellar group of authors that provides us with a true state-of-the-art presentation in these 2 issues on this important subject matter.
They provide an overview of the contributed articles in the following guest editorial. Of particular note is the evolution of the role of both single-photon emission computed tomography and positron emission tomography (PET) methodology. Clinically available PET studies include both 18F-fluorodeoxyglucose and 18F-fluoride. It is proposed that the latter could eventually displace 99mTc-methylene diphosphonate as the routine agent for bone scanning. Rectilinear scan studies using one of the 511-keV annihilation photons of 18F-fluoride actually were proposed by Dr Monte Blau and utilized by Dr Saul Winchel and other investigators 40 years ago. The relative lack of sophisticated equipment to optimally image the 511-keV emission of positron did not make it a feasible option at that time. The current availability of modern generation PET/computed tomography has greatly revived interest in this radiotracer.
We thank our guest editors for putting these issues together and hope that our readers find it informative.
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