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Title: Development of Californium-252 Miniature Source Assemblies

Abstract

The purpose of this CRADA between ORNL and lsotron, Inc. is to develop miniature californium-252 sources configured for remote handling that can be used in neutron brachytherapy for treatment of cancer. Brachytherapy places the · radioactive source at or near the site of the tumor, using a catheter. The CRADA ran from late 1999 through November 2005. The heart of a Cf-252 source is the radioactive core wire, which is sealed inside a metallic source capsule. Previous Cf-252 medical sources were based on a cermet wire with californium oxide dispersed in palladium, typically >1-mm diameter and <0.1% Cf-252 by weight. Previously, the standard medical source in the U.S. was the Applicator Tube (AT) source. 23-mm long, 2.8-mm diameter, with ~30 {micro}g of Cf-252, and which required manual loading into patients by medical staff. The goal of this work was to develop capabilities and technology to fabricate higher-intensity Cf-252 sources attached to a positioning cable, with overall diameter approaching that of exist ing photon (iridium-192) brachytherapy sources (i.e., ~1.1 mm). This work was successful in developing and demonstrating new technologies and procedures for the fabrication of miniaturized Cf-252 sources. CRADA-designed equipment reduced the wire diameters significantly (patent pending). Short wire segmentsmore » were cut and successfully welded inside capsules meeting the miniaturization goals. A batch of seven prototype sources was prepared that met fabrication specifications. Although their neutron emissions were not maximized, they were still several times more intense than the previous AT sources. Very robust source-to-cable attachment methods were demonstrated (patent issued). A shipping canister was designed and built to contain the completed source assembly. lsotron designed and built a computer-controlled remote afterloader system to deliver the new sources for treatments.« less

Authors:
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
Sponsoring Org.:
USDOE Office of Science (SC); USDOE Office of the Secretary of Energy Advisory Board (AB)
OSTI Identifier:
939627
Report Number(s):
ORNL99-0558
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 07 ISOTOPE AND RADIATION SOURCES

Citation Formats

Notspecified, N. A. Development of Californium-252 Miniature Source Assemblies. United States: N. p., 2007. Web. doi:10.2172/939627.
Notspecified, N. A. Development of Californium-252 Miniature Source Assemblies. United States. doi:10.2172/939627.
Notspecified, N. A. Tue . "Development of Californium-252 Miniature Source Assemblies". United States. doi:10.2172/939627. https://www.osti.gov/servlets/purl/939627.
@article{osti_939627,
title = {Development of Californium-252 Miniature Source Assemblies},
author = {Notspecified, N. A.},
abstractNote = {The purpose of this CRADA between ORNL and lsotron, Inc. is to develop miniature californium-252 sources configured for remote handling that can be used in neutron brachytherapy for treatment of cancer. Brachytherapy places the · radioactive source at or near the site of the tumor, using a catheter. The CRADA ran from late 1999 through November 2005. The heart of a Cf-252 source is the radioactive core wire, which is sealed inside a metallic source capsule. Previous Cf-252 medical sources were based on a cermet wire with californium oxide dispersed in palladium, typically >1-mm diameter and <0.1% Cf-252 by weight. Previously, the standard medical source in the U.S. was the Applicator Tube (AT) source. 23-mm long, 2.8-mm diameter, with ~30 {micro}g of Cf-252, and which required manual loading into patients by medical staff. The goal of this work was to develop capabilities and technology to fabricate higher-intensity Cf-252 sources attached to a positioning cable, with overall diameter approaching that of exist ing photon (iridium-192) brachytherapy sources (i.e., ~1.1 mm). This work was successful in developing and demonstrating new technologies and procedures for the fabrication of miniaturized Cf-252 sources. CRADA-designed equipment reduced the wire diameters significantly (patent pending). Short wire segments were cut and successfully welded inside capsules meeting the miniaturization goals. A batch of seven prototype sources was prepared that met fabrication specifications. Although their neutron emissions were not maximized, they were still several times more intense than the previous AT sources. Very robust source-to-cable attachment methods were demonstrated (patent issued). A shipping canister was designed and built to contain the completed source assembly. lsotron designed and built a computer-controlled remote afterloader system to deliver the new sources for treatments.},
doi = {10.2172/939627},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jun 26 00:00:00 EDT 2007},
month = {Tue Jun 26 00:00:00 EDT 2007}
}

Technical Report:

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  • This document describes the development and approach for the radiological characterization of Cf-252 sealed sources for shipment to the Waste Isolation Pilot Plant. The report combines information on the nuclear material content of each individual source (mass or activity and date of manufacture) with information and data on the radionuclide distributions within the originating nuclear material. This approach allows for complete and accurate characterization of the waste container without the need to take additional measurements. The radionuclide uncertainties, developed from acceptable knowledge (AK) information regarding the source material, are applied to the summed activities in the drum. The AK informationmore » used in the characterization of Cf-252 sealed sources has been qualified by the peer review process, which has been reviewed and accepted by the Environmental Protection Agency.« less
  • An improved /sup 252/Cf neutron source form has been developed to enhance containment of /sup 252/Cf during production of the sources and to lower the sale price of /sup 252/Cf sources by commercial encapsulators. Process steps are described for preparing califomnium oxide-palladium cermet powder by palladium chemical plating, fabrication of cermet pellets by pressing and sintering, fabrication of bare wire by rolling, and adjustment (reduction) of / sup 256/Cf linear concentration by roll cladding. /sup 252/Cf is distributed uniformly in the wires, which can be made in concentrations suitable for a full range of industrial source strengths (from 1 xmore » 10/sup 7/ to 2.6 x 10/sup 10/ n/ sec). These processes were developed in laboratory tests with stead-ins and /sup 252/Cf tracer, and were demonstrated with milligram quantities of /sup 252/Cf in the Target Fabrication Facility (TFF). Improved wire forming techniques are being developed to manufacture clad wire on a larger scale. (auth)« less
  • A large water moderated lattice of Zircaloy-4 rods filled with thoria pellets was used to test the cross sections of thorium, Zircaloy-4, hydrogen and oxygen, and to measure the neutron age using the indium activation technique. A 5-milligram /sup 252/Cf source was located in the central rod position of the lattice, and cadmium-covered indium foils were used inside the rods to measure the radial distribution of the 1.46 eV neutron flux from approximately 4.5 to 70.0 centimeters from the source. The measured distribution compared with a higher approximation of a one-dimensional P3 calculation. The measured age of 61.4 +- 1.4more » cm/sup 2/ obtained by numerical integration of the experimental data is in good agreement with the calculational age of 60.1 cm/sup 2/. (NSA 30: 34243)« less