Rubidium-86 is commonly used as a tracer of potassium and can be used for rubidium uptake assays. Rb-86 is one of the highest energy (beta or gamma emitting) radionuclides encountered in UM research laboratories, although not routinely, and requires special care. Rubidium Rb-86 was used to measure of the endocardial distribution of left ventricular coronary blood. Besides, this agent was studied in Duchenne muscular dystrophy in the detection of carriers of the gene. In addition, Rb-86 participated in a clinical trial in patients with benign breast lesions, and stage I/II, stage III/IV untreated breast cancers to study its uptake by the red blood cell (RBC). It was found that the RBC potassium content was slightly increased in the cancer patients and was suggested that the decreased uptake is a cancer-related phenomenon.

Selenomethionine, DL- is the racemic mixture of the D and L enantiomers of Selenomethionine, that used us animal’s dietary supplement. Selenomethionine, DL- was tolerated by chickens for fattening at up to 1.5 mg selenium supplemented/kg feed; Selenomethionine, DL- is therefore safe for chickens for fattening provided total dietary selenium does not exceed 0.5 mg/kg complete feed; this conclusion is extended to all animal species. Based on available toxicity studies and previous assessments of closely related compounds, it is concluded that selenium from Selenomethionine, DL- does not elicit any adverse effects not expected in a selenium compound. The use of Selenomethionine, DL- in animal nutrition is expected to result in a similar increase in selenium deposition in animal tissues/products as that resulting from other sources of Selenomethionine, DL- . To ensure consumer safety from consumption of food originating from animals fed Selenomethionine, DL-, dietary selenium supplementation from the additive should not exceed a maximum of 0.2 mg Se/kg complete feed. Although a Selenomethionine, DL- containing additive did not release any measurable dust, the additive is considered as a hazard by inhalation, which requires protection measures for users since the additive is not the subject of authorisation, and selenium is highly toxic. The additive is not an irritant to skin and eyes and is not a dermal sensitiser. The use of Selenomethionine, DL- in feed does not pose an additional risk to the environment, compared with other sources of selenium for which it will substitute, as long as the maximum authorised content in complete feed is not exceeded.