Abstract: The present invention provides a method for determining a background count rate in liquid scintillation counting. The method comprises measuring an external standard spectrum (201, 202) of a sample, determining, from the external standard spectrum, an external standard count rate within an energy window (203), determining, based on the external standard count rate within the energy window, a background reference parameter, and determining, based on the background reference parameter, the background count rate from a background reference curve (301).

Abstract: The present invention provides a method for determining a background count rate in liquid scintillation counting. The method comprises measuring an external standard spectrum (201, 202) of a sample, determining, from the external standard spectrum, an external standard count rate within an energy window (203), determining, based on the external standard count rate within the energy window, a background reference parameter, and determining, based on the background reference parameter, the background count rate from a background reference curve (301).

Abstract: A homogenous bioassay including i) a first group containing a short lifetime fluorescent acceptor, and ii) a second group containing a quencher, with the first and second groups linked by at least a first linkage. The bioassay measures the acceptor's fluorescence increase resulting from cleavage of the first linkage and also includes iii) a third group containing a donor for energy transfer to the acceptor, where the donor is an up-conversion fluorescent compound, a long-lifetime fluorescent compound or an electrogenerated luminescent compound. A conformational or terminal epitope is created on the first group through linkage cleavage, and the third group includes a binder with affinity for this epitope. The acceptor's fluorescence is caused by exciting the donor. Also disclosed are bioassay kits for this method.

Abstract: A method to correct measurement error in a resonance energy-transfer assay, including exciting anti-Stokes photoluminescent donors with at least one wavelength of light which is greater than an emission wavelength of acceptor molecules; measuring emission at the acceptor's emission wavelength and which differs from the donor's emission wavelength in at least two different time windows; a first time window within the time window defined by the excitation light pulse and a second non-overlapping time window which follows the first time window; and correcting the emission signal, which includes signals originating from non-radiative and radiative energy transfer, within the first time window by estimating the ratio of the signals from non-radiative and radiative energy transfer or the signal originating from radiative energy transfer using at least one emission signal measured in the second time window.

Abstract: A homogenous bioassay including a first group including an acceptor which is a short lifetime fluorescent compound capable of energy transfer, and a second group including a quencher which is capable of energy transfer from an acceptor. The increase or decrease of the acceptor's fluorescence resulting from lengthening or shortening of the distance between the acceptor and quencher is measured. The bioassay also includes a third group including a donor for energy transfer to the acceptor, which donor is an up-conversion fluorescent compound, a long-lifetime fluorescent compound or an electrogenerated luminescent compound. The first group includes a tag, the third group includes a binder having a high affinity for binding to the tag. Fluorescence of the acceptor is brought about by exciting the donor resulting in energy being transferred from the donor to the acceptor.

Abstract: The invention relates to a method for preparing a saline solution comprising [13N]NH4+. The method comprises following steps: preparing [13N]NH3 gas, transporting [13N]NH3 gas to a diffusion chamber, to a first side of a semipermeable membrane, transporting sterile saline solution to the diffusion chamber, to a second side of a semipermeable membrane, allowing the mixing of [13N]NH3 gas that has penetrated the semipermeable membrane with the saline solution on the second side of the semipermeable membrane, whereby saline solution comprising [13N]NH4+ is obtained, and directing the saline solution comprising [13N]NH4+ out from the diffusion chamber. The invention relates also to use of a device for preparing a radiolabelled saline solution for preparation of a saline solution comprising [13N]NH4+.

Abstract: A device for preparing a radioactive water solution to be infused in a patient includes a reaction chamber (13) in which radioactive water vapour is formed by the catalysed reaction of oxygen gas containing oxygen-15 and hydrogen gas. A diffusion chamber (14) is provided which allows the radioactive water to penetrate, but which prevents the penetration of gasses. Tubes (26) and valves (16, 18) direct a sterile saline solution to the diffusion chamber (14), and then direct the saline solution containing radioactive water out from the diffusion chamber to a patient, or to a decay coil (22) being a part of the device. A measuring instrument is provided for measuring the radioactivity of the radioactive solution. The device is characterized in that the diffusion chamber (14), the tubes (26) the valves (16, 18), the radioactivity measuring instrument (17), and preferably also the reaction chamber 913), are mounted in the same frame 50, whereby they form a separate unit i.e.