[en] We report the results of design studies for a multicrystal detector with the capacity to encode the Depth-Of-Interaction (DOI). These studies are based on a simulation that treats the interactions of γ- rays and tracts simulation protons in state-of-the-art position encoding PET detectors. The simulation was used to study the impact of a simple modification to the standard surface treatment of the EXACT HR PLUS block that induces a significant sensitivity of the photopeak pulse height upon DOI of 511keV γ-rays. The depth resolution achieved with the altered block as well as the impact of the modification on its energy and position resolutions are presented. The results show a depth resolution of 6 to 7 mm for the inner crystals of the modified block. This is achieved at the cost of 16% less position addressing accuracy. (author)

[en] Monitoring of the response of tumors to gammagraphic therapy requires a sufficient accumulation of the radiopharmaceutical in the tumor prior to the treatment. A study was made with a view to selecting a subgroup of sarcomas (both bone sarcomas and soft tissue sarcomas) where monitoring based on the use of ^99mTc-MIBI is feasible. A higher probability of high MIBI accumulation ratios was found for patients with tumors larger than 5 cm in size located in limbs. The MIBI accumulation ratio was unaffected by histological grading

[en] Progress in three areas of research is summarized. These are as follows: Labeling Monoclonal antibodies (MAbs) with Tc-99m and Re-186; human melanoma tumors and specific MAbs; evaluation of biological response modifiers (BRM). The techniques of labeling MAbs (IgM, IgG, F(ab')₂ or F(ab')) with Tc-99m was developed in the author's laboratory in 1989 and that with Re-186 in 1992. The techniques are in daily use in the laboratory since then and are adapted to a convenient kit formulation. The metal ions are bound at MAb sulfhydryls generated by a controlled reduction of a pair of disulfide groups. At least two types of MAbs labeled with Tc-99m by this method have been administered into patients and excellent diagnostic results have been obtained. Over the past two and a half years the author has been successfully growing human melanoma tumors in athymic Balb/c nude mice. The cell LINE, WM-9, was obtained from Dr. D Herlyn's laboratory at Wistar Institute in Philadelphia. Sufficient quantities of antihuman melanoma specific antibodies ME 31.3 (Wistar, IgG-1) and MEM-136 (Hybritech, IgG-2A) and their F(ab')₂ fragments are also available in the laboratory. The use of BRM is a rapidly evolving field. Over the past four years, the author has evaluated a number of BRMs in a quest for agents that may augment MAb tumor uptake. These included interferon-α; a pokeweed mitogen and Ukrain, an alkaloid separated from a plant Chelideonium Majis. In these preliminary studies, normal Balb/c mice were used and the BRMs were given i.p. one hour prior to the i.v. administration of tumor necrosis factor or an MAb (TNT-F(ab')₂) labeled with Tc-99m which served as an imaging agent. Animals were sacrificed at 1.5 hr or 4 hrs post-injection. Highlights of the work are given here in a table

[en] The evaluation of cortical damage to the kidneys, especially in children, is currently performed by means of Tc99m-DMSA renal scan. The routine involves the acquisition of planar images and their qualitative and quantitative evaluation. Many studies have dealt with the possible advantage that SPECT could possess on qualitative criteria. This study attempts to quantitatively deal with the issue by the calculation of an index. The results exhibit a clear advantage of tomographic and 3D reconstructed images over the conventional planar ones. (authors)

[en] Study Objective: To determine the peak bone mass density among residents of Metro Manila using dual X-ray absorptiometry (DEXA). Design: Cross-sectional study. Setting: Philippine General Hospital, a university based tertiary care hospital, and St. Luke's Medical Center, a private tertiary care center. Subjects: Forty five (45) healthy subjects aged 15-50 years old, all current residents of Metro Manila, were randomly chosen from among hospital companions were included in the study. There were 23 females and 22 males, with 3 to 4 subjects for each age range of 5. Methods: Bone mass density measurements on the lumbar spine and the femur using dual X-ray absorptiometry (DPXL Lunar) were taken. The values were also age-matched and matched with that of a young adult based on programmed Caucasian norm provided by Lunar Co. The values were then scattered against age for each sex. Ten (10) cc of blood was also extracted from the patients, with the 5 cc of blood separated for future studies. Parathormone assay and biochemistry examinations were also done. Patents were also interviewed as to their lifestyle, diet, use of contraceptive pill or hormonal replacement treatment, using a Filipino version of the revised questionnaire on the WHO Study on Osteoporosis. Dietary content was estimated using a previous day food recall. Results: The mean weight and height for females were 59.48±16.34 kg and 153.52±5.09 cm respectively, and for males, 58.14±10.06 kg and 162.52±6.75 cm respectively. The mean bone mass density at the L₂L₄ level for females was 1.12±0.11 g/cm² and 0.91±0.11 g/cm² at the femur. The highest BMD in both the lumbar spine femoral neck measurements among females was achieved among those aged 30-35 years of age with the lowest BMD occurring between 15-19 and 45-50 years of age in the lumbar spine among female subjects. The highest BMD at the lumbar spine and the femoral neck among males was achieved between the ages 30-35 years of age with the lowest IND occurring between the ages 15-20 years old and incidentally in 2 subjects with ages between 40-44. There seems to be little bone loss among males beyond the age 35, unlike in the females. Conclusions: Bone mass density among a sample of Metro Manila residents was determined using DEXA and the measurements on the lumbar spine and femoral neck. These were age-matched and matched with that of young adult based on Caucasian norm provided by the Lunar Co. Peak bone mass density in the L₂L₄ level among the females is reached between the ages 30-35 years old, after which there is progressive bone loss with values in the 45-50 years old approximating the values in the 15-19 years old age range. A similar pattern is seen in the measurements taken at the femoral neck. Among males, the peak BMD is reached during the 30-35 years old, but there seems to be no rapid decline or rapid bone loss occurring thereafter, unlike in the female subjects. (author)

[en] The primary goals of this project were twofold: (1) Development of a microsensor that would demonstrate the capability for in vivo monitoring of a radiopharmaceutical after its injection into a test animal; and (2) Exploration of capillary electrophoresis (CE) as a separation technique for the analysis of radiopharmaceuticals that are mixtures of different compounds. The combination of in vivo sensors for real-time monitoring of specific chemical states of a radiopharmaceutical in individual organs and CE for analysis of radiopharmaceuticals prior to injection would provide valuable information regarding the fate of an imaging agent after administration. Such information should give insight into strategies for the development of more efficacious radiopharmaceuticals

[en] The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of β cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author)

[en] Fifty patients admitted to Khartoum Teaching Hospital and Shaab Teaching Hospital in the period from October 1994- October 1996 and diagnosed as Pott's disease of spine were included in the study. Patients below the age of 15 years were excluded. Full history and physical examination were performed in each patients. Haemoglobin concentration, Packed cell volume . (PCV) Erythrocyte Sedimentation Rate (ESR), White Blood Cell Count total and differential were done for all patients together with chest X-Ray, spinal X-Ray A. P. and lateral views. Myelogram, CT Scan, Mantoux and CSF examinations were done when needed.The main age of the study group was 41.3±17.6 years, with male to female ratio of 30-20 (3:2). Tuberculoses spondylitis affect the cervical spines in 2 cases (3.45%), the upper thoracic in 10 cases (17.24%), mid thoracic 20 times (34.48%), lower thoracic 20 cases (34>48%), lumber spines 6 cases (10.35%) and no lesion in the sacral spines. Pulmonary tuberculosis was found in 18 patients (36%) together with Pott's disease of the spine.All patients came with back pain, lower limbs weakness and the course of the disease was progressive, 35 patients (70%) were unable to walk, and the sphincters were affected in 37 patients (74%) of the cases.On medical treatment 37 patients (74%) showed progressive improvement, 5 patients (10%) remained static or deteriorated and 8 patients (16%) died. 2 of those who died had developed severe bed sores and anemia before death, 3 of them developed deep vein thrombosis (DVT) and died even though they started anticoagulant therapy, two patients developed drug induced hepatitis and died in spite of stopping the drugs, and one patient had got militry tuberculosis showed no adverse effect on outcome of treatment. Surgery done on two patients showed good outcome.(Author)

No abstract available

[en] Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Osteoporosis is an enormous public health problem, because it causes multiple fractures in the elderly people, and huge health care cost. The progressive aging of the world's population predicts a substantial increase in the global burden of osteoporosis, so further studying and preventing osteoporosis are often important problems. Since 1986 our department started large investigation of BMDat forearm using single photon absorptiometry (SPA) and in 1991-1993 was undertook Investigation of bone mineral density at the lumbar spine and proximal femur in normal Chinese population using Dual Energy X-ray Absorptiometry(DEXA). The results showed the BMD of all above sites is age-related, the age of peak BMD is different at the forearm, lumbar spine and hip, and the difference is related with sex. After the age of peak bone mass, BMD steadily declined with advancing age. In the Co-ordinated Research Programme on Comparative International Studies of Osteoporosis using Isotope Techniques. The first, we will further study age-, sex-related changes in bone mass among Chinese northern healthy residents in urban. Not only consider that chronic disease and medicine influence on osteoporosis, also consider the influence of life-style factors. The second, the trace elements of tooth and hair samples will be analysed by neutron activation analysis (NAA). It try to find the correlation of trace elements composition between tooth and hair samples. The possible difference in theses elements between osteoporotic patients and controls. (author)