Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a neutron flux of a first isotope in a subterranean formation; calculating, based at least in part on the determined neutron flux of the first isotope, a predicted production rate of a second isotope in the subterranean formation; calculating a first ratio of the predicted production rate of the second isotope relative to a theoretical production rate of a stable form of the second isotope; measuring respective concentrations of the second isotope and the stable form of the second isotope in a subterranean water sample; calculating a second ratio of the measured concentration of the second isotope relative to the measured concentration of the stable form of the second isotope; and based on a comparison of the first and second ratios, determining that the subterranean formation is suitable as a hazardous waste repository.

Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a neutron flux of a first isotope in a subterranean formation; calculating, based at least in part on the determined neutron flux of the first isotope, a predicted production rate of a second isotope in the subterranean formation; calculating a first ratio of the predicted production rate of the second isotope relative to a theoretical production rate of a stable form of the second isotope; measuring respective concentrations of the second isotope and the stable form of the second isotope in a subterranean water sample; calculating a second ratio of the measured concentration of the second isotope relative to the measured concentration of the stable form of the second isotope; and based on a comparison of the first and second ratios, determining that the subterranean formation is suitable as a hazardous waste repository.

Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a concentration of at least one noble gas isotope of a plurality of noble gas isotopes in fluid sample from a subterranean formation below a terranean surface; determining a produced amount of the at least one noble gas isotope in the subterranean formation based on a production rate of the at least one noble gas isotope and a minimum residence time; calculating a ratio of the determined concentration of the at least one noble gas isotope in the fluid sample to the determined produced amount of the at least one noble gas isotope; and based on the calculated ratio being at or near a threshold value, determining that the subterranean formation is suitable as a hazardous waste repository.

Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a concentration of at least one noble gas isotope of a plurality of noble gas isotopes in fluid sample from a subterranean formation below a terranean surface; determining a produced amount of the at least one noble gas isotope in the subterranean formation based on a production rate of the at least one noble gas isotope and a minimum residence time; calculating a ratio of the determined concentration of the at least one noble gas isotope in the fluid sample to the determined produced amount of the at least one noble gas isotope; and based on the calculated ratio being at or near a threshold value, determining that the subterranean formation is suitable as a hazardous waste repository.

An infusion system (10) including a radioisotope generator (52) that generates a radioactive eluate via an elution, an activity detector (58) configured to measure an activity of a first radioisotope in the radioactive eluate generated by the radioisotope generator, and a controller (80). The controller can track a cumulative volume of radioactive eluate generated by the radioisotope generator and also track the activity of the first radioisotope in the radioactive eluate generated by the radioisotope generator. The controller can determine a predicted volume of the radioactive eluate generated by the radioisotope generator at which the activity of the first radioisotope in the radioactive eluate will reach a threshold based on the tracked cumulative volume of the radioactive eluate and the tracked activity of the first radioisotope. This information can be useful for proactively removing the radioisotope generator from service and/or replacing the radioisotope generator with a fresh generator.

An infusion system (10) including a radioisotope generator (52) that generates a radioactive eluate via an elution, an activity detector (58) configured to measure an activity of a first radioisotope in the radioactive eluate generated by the radioisotope generator, and a controller (80). The controller can track a cumulative volume of radioactive eluate generated by the radioisotope generator and also track the activity of the first radioisotope in the radioactive eluate generated by the radioisotope generator. The controller can determine a predicted volume of the radioactive eluate generated by the radioisotope generator at which the activity of the first radioisotope in the radioactive eluate will reach a threshold based on the tracked cumulative volume of the radioactive eluate and the tracked activity of the first radioisotope. This information can be useful for proactively removing the radioisotope generator from service and/or replacing the radioisotope generator with a fresh generator.

Techniques for imaging radioactive emission in a target volume include receiving data indicating a set of one or more known emission energies associated with a high energy particle source and determining a Compton line for each emission energy in the set. A Compton camera collects location and deposited energy from an interaction associated with a single source event from a target volume of a subject. For the single source event, an earliest deposited energy, E.sub.1, and first scattering angle, .sub.1, and a cone of possible locations for the source event are determined. A particular location for the high energy particle source within the target volume without including the single source event, if E.sub.1 is not within a predetermined interval of the Compton line for at least one of known emission energies. A solution is presented on a display device.

Techniques for imaging radioactive emission in a target volume include receiving data indicating a set of one or more known emission energies associated with a high energy particle source and determining a Compton line for each emission energy in the set. A Compton camera collects location and deposited energy from an interaction associated with a single source event from a target volume of a subject. For the single source event, an earliest deposited energy, E.sub.1, and first scattering angle, .sub.1, and a cone of possible locations for the source event are determined. A particular location for the high energy particle source within the target volume without including the single source event, if E.sub.1 is not within a predetermined interval of the Compton line for at least one of known emission energies. A solution is presented on a display device.

A method for determining a radionuclide concentration of a material is provided. The method comprises placing a detector in a protective structure, wherein the detector is coupled to a single-channel analyzer. The method further comprises inserting the protective structure in a material, wherein the material comprises a radionuclide. The method additionally comprises measuring the moisture content of the material to be analyzed. The method also comprises counting the emitted radiation having a known energy over an interval of time to produce a count per time, wherein the emitted radiation is emitted from the radionuclide and then dividing the count per time by the weight of the material to produce a count per time per weight.

A method for determining a radionuclide concentration of a material is provided. The method comprises placing a detector in a protective structure, wherein the detector is coupled to a single-channel analyzer. The method further comprises inserting the protective structure in a material, wherein the material comprises a radionuclide. The method additionally comprises measuring the moisture content of the material to be analyzed. The method also comprises counting the emitted radiation having a known energy over an interval of time to produce a count per time, wherein the emitted radiation is emitted from the radionuclide and then dividing the count per time by the weight of the material to produce a count per time per weight.