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K F Eckerman

Publications and source records attributed to K F Eckerman.

4 recordsLinked to original sources
PubMed1990

Source inventory limits.

A new set of values has been developed for exempting sealed sources of radioactive materials from inventory. The criteria for exemption are: (a) the annual occupational dose from external radiation at 1 m from the source is approximately 100 microSv (10 mrem) or less; and (b) the source activity is approximately equal to the annual limit on intake by inhalation or less than 4 X 10(7) Bq (1000 microCi). These criteria were selected to correspond to an annual occupational dose of approximately 50 to 500 microSv (5 to 50 mrem) and a small potential annual risk of approximately 1 X 10(-6) to 1 X 10(-5) fatal cancers or less.

Radiation Protection↗
PubMed1989

A model of the peritoneal cavity for use in internal dosimetry.

Several therapeutic and diagnostic techniques involve injection of radioactive material into the peritoneal cavity. Estimation of the radiation dose to the surface of the peritoneum or to surrounding organs is hampered by the lack of a suitable source region in the phantom commonly used for such calculations. We have modified the Fisher-Snyder phantom to include a region representing the peritoneal cavity which may be employed to estimate such radiation doses. A geometric model is described which is coordinated with the existing organ regions in the phantom. Specific absorbed fractions (derived by Monte Carlo techniques) for photon emissions originating within the cavity are listed. Photon S-values for several radionuclides which have been administered intraperitoneally are shown. Dose conversion factors for electrons irradiating the peritoneal cavity wall, from either a thin plane or volume source of activity within the cavity, are also given for several nuclides.

Electrons↗
PubMed1987

Increased delivery of tumor-specific monoclonal antibodies to brain after osmotic blood-brain barrier modification in patients with melanoma metastatic to the central nervous system.

We evaluated the delivery of melanoma-specific radiolabeled monoclonal antibody (MAb) Fab fragments in a pilot study of three patients with melanoma metastatic to the central nervous system. Tumor samples demonstrated excellent immunohistochemical reactivity with Fab 96.5, specific for a 97,000-molecular-weight melanoma antigen (p97), or Fab 48.7, specific for a melanoma-associated proteoglycan antigen. All three patients received 131I-labeled tumor-specific Fab (5 to 7 mg, 1 mCi/mg) intravenously. On a separate occasion, two patients received 131I-labeled nonspecific Fab (5 to 7 mg, 1 mCi/mg). There was no uptake of either antibody into the region of the tumor (as documented by gamma camera brain images). However, there was increased uptake in the blood-brain barrier (BBB)-modified areas in all three patients when radiolabeled tumor-specific MAb was administered intravenously in conjunction with osmotic BBB opening. In one patient, the estimated cerebrovascular permeability X capillary surface area (PA) for the tumor-bearing hemisphere 3 hours after disruption was 1.16 X 10(-6) sec-1 compared to the PA of 0.395 X 10(-6) sec-1 in the nondisrupted hemisphere. Serial brain scans showed that greater than 90% of the radiolabeled antibody cleared from the brain by 72 hours. The highest radiation doses (rads) calculated per 7 mCi injection were: left brain (barrier-modified hemisphere), 5.46; right brain (non-barrier modified hemisphere), 1.68; thyroid, 98; stomach, 9.1; kidney, 39.9; and total body, 1.33. There seemed to be increased uptake of antibody in the tumor region after barrier modification in one patient, but antibody clearance from that region occurred at the same rate as from surrounding and apparently tumor-free brain. In one patient who had carcinomatous meningitis, we demonstrated antibody bound to only a fraction of the antigen binding sites on tumor cells in the cerebrospinal fluid after BBB modification. We have not shown distinct, persistent localization of antibody in brain tumor; studies investigating MAb dose and other parameters as the basis for this problem are under way.

Antibodies, Monoclonal↗