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PubMed2004

[Radiosurgery: basic principles].

Radiosurgery is a way of treating in-brain lesions which uses convergence of very thin multiple ionisation beams in a unique focus point coinciding with the target. This enables obtaining a therapeutic effect without opening the skull, and thus avoiding eventual complications or contraindications of classical neurosurgery. In certain cases irradiation can be delivered with submillimetric precision. This particularly new approach is historically essentially based on the work of the Swedish neurosurgeon Lars Leksell in the 50s. Since that time new imaging techniques (e.g. digital imaging) have considerably widened indications. Three ionisation beam sources are generally used in this context: gamma rays emitted by radioactive cobalt 60 sources for the Gamma Knife, high energy LINAC X-rays modified in comparison to their classical use in external radiation therapy, and, more rarely, protons produced in cyclotrons. Several teams world-wide are still perfecting and refining this developing technique.

Ear Neoplasms↗
PubMed1990

Bone allografts sterilised by irradiation. Biological properties, procurement and results of 150 massive allografts.

Massive bone allografts from cadavers have been sterilised by gamma-radiation from radioactive cobalt at a dose of 25,000 gray (Gy). The biological effects of radiation are discussed. Human cortical bone showed an acceptable 20% decrease in strength on bending tests after 27,000 Gy irradiation, but higher doses are more damaging and should be avoided. The procurement protocol used at the Cochin Hospital is described, and the importance of dosimetry and record-keeping emphasised. The clinical results of 150 massive bone allografts are reported. The infection rate was low. The evolution of the graft in each type of reconstruction is analysed and appears to be comparable to nonirradiated allografts. Very few complications occurred after composite reconstructions in the lower limb. Pelvic reconstructions had the highest complication rate, but most were not related to the use of the allograft.

Bone Transplantation↗
PubMed1985

Fetal liver transplantation in the mini-pig.

After the characterisation of the hematological and immunological status of the mini-pig fetus at different gestational ages of development was performed, two different groups of animals receiving 800 rads of TBI given by a radioactive cobalt source at a dose/rate of 5/6 rad/min or 750 rads of TBI given by a Linear Accelerator at a dose/rate of 25/26 rad/min, both in a single dose exposure, were transplanted with a pool of allogeneic fetal liver cells whose age ranged between 55 and 75 days of gestation. In the first group 1 animal out of 6 is alive and well 30 months post-transplant. In the second group one of the nine transplanted animals survived 78 days. Engraftment was proved by the presence of the donor chromosome in the proliferating bone marrow cells in one animal.

Animals↗
PubMedDate not supplied

[A case of tumor of the pineal body treated with gamma rays of Co-60].

A 21-year-old patients was admitted to hospital with symptoms suggesting a tumour in the area of the epiphysis. Computer tomography confirmed the initial diagnosis. Since signs were present of increased intracranial pressure a Pudenz valve was implanted and in the second stage of treatment radiotherapy with radioactive cobalt was applied. A very good result was obtained with control CT failing to demonstrate presence of the tumour and hydrocephalus.

Adult↗
PubMed1996

[The first century of radiotherapy in France].

The first X-ray treatment ever given to a patient was done by Victor Despeignes of Lyon, five months after Roentgen's discovery. The first brachytherapies with radium emanation (radon) were performed a few years after the discovery (March 1st, 1896) of natural radioactivity by Becquerel and that of radium by the Curies (December 28, 1898). Marie Curie organised the Radium Institute and personally calibrated more than five thousand sources of radium disseminated in various French cancer departments. Bergonie and Tribondeau discovered (1906) the basic laws of tissular radiosensitivity. Since the work of Regaud and Coutard, published in 1925, fractionation has become the widely accepted mode of external radiation therapy. Mallet discovered the Cerenkov effect in 1926 and the Joliot-Curies artificial radioactivity in 1934. After the golden age of 200 kV X-rays and radium applications, the megavoltage era with imported telecobaltherapy units and betatrons began in 1954. Then the first french linear accelerator was manufactured. Recently the national manufacturer of linear accelerators (CGR-MeV) became a branch of General Electric Medical Systems. The French Atomic Energy Commission produces radioactive cobalt, cesium and iridium sources. In France, one century after the discovery of X rays, 326 megavoltage units are operating in 185 cancer centers, 18 university hospital radiotherapy departments, 20 comprehensive cancer centers including the Curie and the Gustave Roussy Institutes, 51 general public hospitals and 96 private clinics for a population of 58 millions inhabitants.

France↗
PubMed1985

[Radioactive and stable cobalt concentrations in mussel in Kyushu islands, Japan].

Two kinds of mussel, Septifer virgatus and Mytilus edulis, were collected from Kyushu island, Japan, in order to elucidate a background level of 60Co, which is one of the most significant radionuclide for environmental monitoring around a nuclear power plant. The mussels were collected from 7 locations in 1983 and classified 2 or 3 groups depending on their shell size at each location. Activities of 60Co were measured by a low-background beta counter after purified by means of chemical separation and electrodeposition. Stable cobalt concentrations were determined by colorimetric method. The concentrations of cobalt in Septifer virgatus are one order higher level than that in Mytilus edulis. There are not so large difference in cobalt content depending on shell size so long as comparing them at the same location. The radioactivities in mussels show the same trend as stable cobalt. It has become apparent that Septifer virgatus has a tendency to concentrate cobalt with growing but Mytilus edulis is opposite. The cobalt-60 introduced to sea from nuclear explosions seems to be relatively constant in coastal seawater since specific activities are distributed in a narrow range in spite of kind, shell size and location.

Animals↗
PubMed1987

Simultaneous determination of radioactive and stable isotopes of cobalt in environmental samples by the isotopic exchange method.

The isotopic exchange method is studied for the simultaneous determination of radioactive and stable isotopes of cobalt in environmental samples. Radioactive cobalt is isotopically exchanged with Co-CyDTA in HC1 solution of the sample. The solvent extraction method is used for the separation of Co2+ and Co-CyDTA species from each other. The amounts of radioactive and stable cobalt isotopes are calculated with activities of Co and Co-CyDTA at the exchange equilibrium. The methods for eliminating interfering ions are discussed. The results are in good concordance with those obtained by the conventional analytical methods.

Cobalt Isotopes↗