Krypton-81m is a radioactive isotope of krypton that is used in medical imaging, particularly in lung ventilation studies. It is a metastable isotope, meaning it has a relatively long half-life of about 13 seconds before it decays to stable krypton-81.
Krypton-81m is produced by bombarding rubidium-81 with neutrons in a nuclear reactor. Once produced, it can be inhaled by a patient and used as a tracer gas to visualize the ventilation of the lungs. The emitted gamma radiation from the decay of Krypton-81m can be detected by a gamma camera, allowing for detailed imaging of lung function.
Lung ventilation studies using Krypton-81m are valuable diagnostic tools for assessing lung function, particularly in patients with respiratory conditions such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary embolism. The non-invasive nature of the procedure and the ability to obtain real-time images make it a useful tool for evaluating lung ventilation and identifying abnormalities.
Research on the use of Krypton-81m in medical imaging continues to explore its potential applications and optimize imaging techniques for better diagnostic accuracy and patient care.
Properties:
Krypton-81m (81mKr) is a gaseous radionuclide with an ultra-short half-life of 13 sec emitting a gamma at 190 keV (67%).
Manufacturing:
81mKr is continuously produced from an 81Rb/81mKr generator. The mother radionuclide 81Rb has a half-life of 4.57h. This radionuclide is immobilized on a membrane, through which the daughter radionuclide is eluted with the passing of air.
Source and availability:
Rubidium-81/Krypton-81m Generator.
Derivatives:
Krypton is an inert gas and can only be used as such. 81mKr is ideally suited to performing functional images of pulmonary ventilation, for example in asthmatic patients, and for the early diagnosis of lung diseases and function (inhalation). Aqueous solutions of 81mKr are used for lung perfusion imaging (iv. Injection).
Price:
This generator can be used only during a single working day and the profitability at the level of the clinic is highly dependent on the number of patients that can be scanned during that same day.
Issues:
The expiry of the generator (only about 20 hours) means that a new generator needs to be supplied every day. The tool is interesting for customers with a high throughput of lung ventilation imaging patients.
Comments:
The very short half-life of 81mKr results in a low radiation burden for the patient, enabling lung ventilation perfusion immediately after a 99mTc lung perfusion study. There are some alternative techniques for lung ventilation such as Technegas or Xenon that are available.