[en] The alpha particle energy spectrum of ²²⁶Ra and its daughters in a bone has been resolved into its components. The peaked nature of this spectrum is interpreted as due to a concentraion of radionuclides near the endosteal surfaces of the bones of this individual. The calculated results have been compared to direct measurements of the ²²⁶Ra and ²⁴¹Po distributions contained by alpha-gamma coincidence techniques

[en] An analytical method utilizing x-ray fluorescence (XRF) spectrometry is described to determine simultaneously the amounts of lanthanum, cerium, praseodymium, and neodymium in air-filter samples collected at a rare-earth processing refinery in Illinois

[en] The Brookhaven LINAC Isotope Producer (BLIP) is the first facility to demonstrate the capability of a large linear accelerator for efficient and economical production of difficult-to-make, medically useful radionuclides. It utilizes the excess beam capacity of a LINAC that injects 200-MeV protons into the 33-GeV Alternating Gradient Synchrotron. The LINAC provides an integrated beam current of 60 μA for radionuclide production, operating 24 hours per day, 7 days per week. The 200-MeV proton energy is very suitable for isotope production since the spallation process provides a route to copious quantities of radionuclides unavailable at lower energy accelerators, or reactors. Further, the energy is high enough to allow simultaneous irradiation of multiple targets leading to reduced cost per nuclide. Careful choice of target position in the array makes it possible to select the proper proton energy range to maximize the yield of a particular nuclide from a given target and minimize the amounts of undesirable by-products

[en] Proton irradiation of natural and enriched SrCl₂ targets was used to produce PET radioisotope ⁸⁶. The proton energy was degraded from the incident 117.8 MeV to induce the ⁸⁸Sr(p,3n) reaction. For the irradiation three pellets made of ^natSrCl₂ (6.61 and 74.49 g) and ⁸⁸SrCl₂ (5.02 g) were pressed and individually encapsulated in stainless steel target bodies. The two smaller targets were irradiated for 0.5-1 h at the energy - 46 → 37 MeV to take advantage of the peak in the excitation function of the ⁸⁸Sr(p,3n) reaction. The larger target was irradiated at 66.4 → 44.6 MeV. The irradiated pellets were chemically processed to selectively separate ⁸⁶Y radioisotope using Eichrom DGA (N,N,N(prime),N(prime)-tetra-n-octyldiglycolamide) resin. The production yields of ⁸⁶Y were determined to be 10-13 mCi/μA h. Coproduction of ^87mY in the final product was 34% for ^natSrCl₂ and 54% for ⁸⁸SrCl₂ target. The chemical separation yield of yttrium reached 88-92%. The developed chemical procedure allows for the same day processing and shipment of the isotope to users.

[en] The alpha particle energy spectrum of ²²⁶Ra and its four alpha emitting daughters in an ashed, ground bone sample has been resolved into its components using a computerized spectrum stripping algorithm. These calculated results have been compared to direct measurements of the ²²⁶Ra and ²¹⁴Po distributions obtained by alpha--gamma coincidence techniques. The ability of the calculation to deconvolute the total spectrum into its five alpha components implies that straightforward alpha counting may be used instead of the very low efficiency ²²⁶Ra alpha--gamma coincidence method. From knowledge of the actual ²²⁶Ra distribution, along with suitable detector energy and efficiency calibrations, one could determine endosteal cell dose rate empirically

[en] By bombarding natural krypton gas with approx. 63 MeV protons, ⁸¹Rb is formed by (p,4n) reaction from high abundance ⁸⁴Kr (57%) as well as some additional contribution from ⁸³Kr (11.5%) and ⁸²Kr (11.6%) by (p,3n) and (p,2n) reactions, respectively. The production rate of ⁸¹Rb is typically 1.5 mCi/μAh. This production rate is sufficient to create up to several hundred millicuries per run if necessary, enough for several high activity ⁸¹Rb/sup 81m/Kr generators. Presently generators that deliver 10 to 20 mCi to the lungs are produced weekly for on-site use. The only other important activity in the solution is Rb-82m (6.4 hr). Small amounts of Br-76 (16.1 hr), Br-77 (57 hr), Br-82 (35.5 hr), Rb-83 (86.2 d), and Rb-84 (33 d) were also present. The bromine impurities pose no problem since they are not trapped on the generator. Rb-82m and Rb-84 decay to stable Kr-82 and Kr-84 in the generator and do not interfere with Kr-81m studies

[en] Although the production of radioisotopes in reactors or in low to medium energy cyclotrons appears to be relatively well established, especially for those isotopes that are routinely used and have a commercial market, certain isotopes can either be made only in high-energy particle accelerators or their production is more cost effective when made this way. These facilities are extremely expensive to build and operate, and isotope production is, in general, either not cost-effective or is in conflict with their primary mandate or missions which involve physics research. Isotope production using high-energy accelerators in the US, therefore, has been only an intermittent and parasitic activity. However, since a number of isotopes produced at higher energies are emerging as being potentially useful for medical and other applications, there is a renewed concern about their availability in a continuous and reliable fashion. In the US, in particular, the various aspects of the prediction and availability of radioisotopes from high-energy accelerators are presently undergoing a detailed scrutiny and review by various scientific and professional organizations as well as the Government. A number of new factors has complicated the supply/demand equation. These include considerations of cost versus needs, reliability factors, mission orientation, research and educational components, and commercial viability. This paper will focus on the present status and projected needs of radioisotope production with high-energy accelerators in the US, and will compare and examine the existing infrastructure in other countries for this purpose

[en] This patent describes a process for producing and isolating technetium-96. It comprises irradiating a high purity rhodium target with protons; dissolving the irradiated rhodium target by electrolysis in an electrolyte; evaporating the resulting solution to remove the electrolyte; dissolving the resulting material in a solvent that makes the solution basic; and extracting the Tc-96 therefrom with an organic solvent

[en] A simple method for the synthesis of 1,4,7, 10-tetraazacyclododecane N,N'N double-prime,N'double-prime-tetraacetic acid and 1,4,8,11-tetraazacyclotetradecane N,N',N double-prime,N'double-prime-tetraacetic acid involves cyanomethylating 1,4,7,10-tetraazacyclododecane or 1,4,8,11-tetraazacyclotetradecane to form a tetranitrile and hydrolyzing the tetranitrile. These macrocyclic compounds are functionalized through one of the carboxylates and then conjugated to various biological molecules including monoclonal antibodies. The resulting conjugated molecules are labeled with radiometals for SPECT and PET imaging and for radiotherapy. 4 figs

[en] Cyclo agents are described which are useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2diamino cyclohexane-N,N,N',N'-tetra acetic acid. No Drawings