[en] The pattern of biodistribution of radiopharmaceuticals may be affected by various agents and therapeutical procedures, chemotherapy agents, thyroid hormones, metals, radiotherapy, surgery, anesthetic agents, dialysis other radiopharmaceutical interactions. Recommendations for the detection of altered biodistribution in patients by causes not directly related with the pathology itself was given. pathology itself was given

[en] A nuclear medicine department caters to the need of all clinical departments, and, therefore, should be located at a central place. At the same time, because of radiation hazard associated with the use of radionuclides, planning of the departments should be done in such a way that there is no radiation exposure to non-radiation workers and the general public, and also that radiation workers handling radioisotopes receive minimum exposure. When a decision to set up a nuclear medicine department is taken, the authorities are faced with a number of questions regarding the location, planning for the premises, equipment needed, availability of trained medical and paramedical personnel and the procedure for obtaining clearance from various authorities

[en] There are some special problems in setting up nuclear medicine in a developing country. They can be briefly described in the form of the following general rules. 1) Impossible triangle. For the practice of nuclear medicine, three things are needed: Instrument, Radiopharmaceutical and a Patient. In a developing country, these three become three sides of an impossible triangle. When the radiopharmaceutical is available, the instrument may not be working; when the instrument is functioning, the radiopharmaceutical may not have been obtained from the foreign supplier; and when both are there, the patient might no longer be in the hospital. Three sides of this triangle never join to become a congruent whole. 2) Reverse square law. Further away one is from the source of supply of instruments and radiopharmaceuticals, the problems multiply by the square of this distance. 3) Future of nuclear medicine is tied to the electrical supply available in a developing country. These problems related to power supply are described in the Chapter on maintenance of instruments

[en] The goal of this Chapter is to give a general outline of the essential principles and procedures for radiation protection in a nuclear medicine department where radionuclides are used for diagnosis and therapy. More detailed recommendations regarding radiation protection in nuclear medicine are given in the publications of the International Commission on Radiation Protection (ICRP, publications 25, 57, 60) and in ILO/IAEA/WHO Manual on Radiation Protection in Hospitals and General Practice (Volume 2: Unsealed Sources, WHO, Geneva, 1975), on which this Chapter is based. This chapter is not intended to replace the above-mentioned international recommendations on radiation protection, as well as existing national regulations on this subject, but intended only to provide guidance for implementing these recommendations in clinical practice

[en] Today, because of the diversity of its applications - radiation and radionuclides for medical and biological purposes are used in more countries and in more laboratories than any other application of atomic energy. International organizations, mainly the IAEA and the WHO, have played a significant role in the spread of this nuclear technology in developing countries. There are altogether 112 member states of the Agency, about 71 of them can be classified as developing countries. Out of them, nearly 56 have some kind of nuclear medicine. By that I mean there is some medical use of radioisotopes, be it imaging, radioimmunoassay or the old thyroid uptake. In most of these countries, the personnel working in nuclear medicine has been trained abroad. Training can be as short as few weeks abroad in the form of attendance at one of the four or six week training courses offered by an international organization. Occasionally it is through a fellowship offered by the same organizations. In terms of technology and training, Nuclear Medicine, in its present form, can thus be considered a high technology imported medicine in many of these countries

[en] A retrospective analysis of 104 chest radionuclide angiography (CRNA) studies establishes the utility of this procedure in the evaluation of pulmonary malignancies and benign masses. Remarkable abnormalities in the perfusion of the lungs were identified in 36 (58%) of 62 cases that were not predictably normal or predictably abnormal from the clinical setting. While 60 of these 62 cases involved malignancy being evaluated for metastases, only 21 (34%) had metastases identified by radionuclide bone or liver-spleen scintigraphy. In addition to diagnosis of superior vena cava obstruction, the CRNA may have a more frequent application as an adjunct to routine scintigraphic studies directed to the identification of metastatic disease

[en] The use of cyclotrons in medical research started in the late 1930s with the most prominent use being neutron irradiation in cancer therapy. Due to a lack of understanding of the biological effect of neutrons, the results were less than encouraging. In the 1940s and 1950s, small cyclotrons were used for isotope production and in the mid 60s, the biological effect of neutrons was more thoroughly studied, with the result that a second trial of neutron therapy was initiated at Hammersmith Hospital, England. Concurrent with this, work on the use of high energy charged particles, initially protons and alphas, was initiated in Sweden and Russia and at Harvard and Berkeley. The English success in neutron therapy led to some pilot studies in the USA using physics cyclotrons of various energies and targets. These results in turn lead to the present series of machines presently being installed at M.D. Anderson Hospital (42 MeV), Seattle (50 MeV) and UCLA (46 MeV). The future probably bodes well for cyclotrons at the two extremes of the energy range. For nuclear medicine the shift is away from the use of multiple isotopes, which requires a large range of particles and energies to ¹¹C, ¹³N, ¹⁵O, and ¹⁸F, which can be incorporated in metabolic specific compounds and be made with small 8-10 MeV p+ ''table top'' cyclotrons. For tumor therapy machines of 60 MeV or so will probably be the choice for the future, as they allow the treatment of deep seated tumors with neutrons and the charged particles have sufficient range to allow the treatment of ocular tumors. (orig.)

[en] Changes in the distribution of the hepatic blood flow induced by intra-arterial infusion of angiotensin II (AT-II) were studied in human hepatic cancers using extremely short-lived radioisotope (RI) (krypton 81 m [/sup 81m/Kr]; half-life, 13 seconds). After the start of continuous infusion of AT-II, the radioactivity of the tumor showed about a two-fold increase, whereas that of the nontumor region decreased to about one half as much as the level before the infusion. Consequently, the mean ratio of the arterial blood flow in the tumor region to that in the nontumor region (T/N ratio) increased to 3.30 (P less than 0.001). The T/N ratio showed a peak before the peripheral blood pressure reached the maximum, and thereafter tended to decrease. Intra-arterial infusion of AT-II raised the T/N ratio more obviously than did intravenous infusion of the drug, with less rise in the peripheral blood pressure. It is believed that intra-arterial infusion chemotherapy with local use of AT-II enables better accessibility of chemotherapeutic drugs to tumors

[en] A hybrid collimator for tomographic imaging with a scintillation camera comprising a coded aperture plate and a parallel plate collimator. The code plate includes a plurality of lateral slits each of which is radiopaque or radiotransparent pursuant to a time modulated code. The parallel plates define a plurality of radiotransparent channels whose lengthwise orientation is orthogonal to the lateral slits of the code plate. In a preferred embodiment, the code plate is advanced across the channels of the collimator in a direction parallel to their lengthwise orientation rendering a time coded pattern that is identical for each channel

[en] An apparatus is described for pulse-echo ultrasonic examination, particularly in medical diagnostic examination comprised of one or more transducer elements for transmitting divergent pulses of ultrasonic energy into the object under examination and a greater number of transducer elements providing a plurality of received beams for each pulse transmitted