Die zerebrale Serienszintigraphie*

The impact of W. K. Röntgen's discovery on the use of internalizable sources of ionizing energy in diagnostic and therapeutic nuclear medicine

The early history of cathode rays, X-rays and a third kind of natural radiation from several minerals and atomic fission is described. In this way the fundamental concept of radioactivity, laws of decay and atomic models were developed. With artificial radioactive isotopes, new tailored radiopharmaceuticals could be introduced into metabolic research, medical diagnostics and therapy. Von Hevesy's concept of the dynamic state of body constituents led to examination of the locations and movements of labelled atoms and molecules as a function of time. That was the birth of nuclear medicine. The principles and value at the molecular level of several specific tracer studies in research and diagnostic or therapeutic use are explained. Typically, diagnostic tests with tracer agents are non-invasive and have low radiation exposure. Competing with other diagnostic and therapeutic modalities, nuclear medicine is a speciality in its own right. But there are moves to classify it as a subspecialization of other organ-oriented clinical disciplines. That is a misunderstanding of the radiologist's role and does not answer the question: What is the best way of working for the patient? New horizons in diagnostic modalities, biochemistry, immunology, imaging and the use of immunogenic therapeutic agents demand a continuous cooperation within interdisciplinary teams. That is as necessary with radiologic departments, participating in changed organizational structures, as with other clinical departments.

Single photon emission computed tomography imaging of brain tumors

Five radiotracers may be used for single-photon emission computed tomography (SPECT) imaging of brain tumors, namely technetium 99m pertechnetate, iodine-123 amphetamine derivatives, 99mTc-hexamethyl propylene amine oxime (HMPAO), thallium 201, and 123I alpha methyl tyrosine. Of these, pertechnetate may be considered as an "historical" procedure in brain tumors. However, there may be some equivocal cases in computed tomography or magnetic resonance imaging, where this procedure may still be used. In 1981, 123I isopropyl amphetamine was first used in brain tumors. Further studies showed, however, that IMP is not a useful tool for brain imaging in tumorous lesions. In 1986, 99mTc HMPAO appeared on the European market as a new tumor imaging agent. Some useful clinical results were obtained in patients before and after chemotherapy or radiotherapy. Thallium-201 was incidentally noted to accumulate in tumors. Using a threshold index, this agent can be used to distinguish low-versus high-grade lesions. The most promising agent for brain tumor SPECT is 123I-alpha methyl tyrosine, which shows potential to evaluate therapeutic procedures in brain tumors and may improve the differentiation between abscess and glioblastoma. The most promising aspect is the differentiation of tumor recurrences and scar tissue after brain surgery.