patient issues


Reservoir System
Model of Kr81m Admin.
Tc99m Perfusion
Standard Study
Dual Energy Acq
Problem Patients
Clinical Reporting

Kr81m Administration

The most efficient method of administration is the reservoir breathing system. This ensures that the initial bolus of activity from the generator is breathed in by the patient and also that the generator flow is stored while the patient breathes out.

It is very inefficient to operate without  a reservoir system. This can be seen from our model of patient lung activity. This also shows that asking a patient to take deep breaths is also inefficient. Normal tidal breathing (as long as it is not too shallow) is more efficient and also avoids excessive lung movement during imaging.

Tc99m Perfusion

Do you inject with the patient sitting up or supine? Preferably inject with the patient in the same orientation as the images.

Patient Protocols

A good standard protocol involves administering the Kr81m immediately after each Tc99m perfusion view so avoiding any patient movement. It is possible to carry out the Tc99m and Kr81m study simultaneously with a dual energy window. However it is important to be aware of downscatter from Kr81m into the Tc99m window.

Paediatric imaging brings its own problems! Some tips are given.

Clinical Reporting

Lung reporting can be a complex as well as a simple issue. A normal study is usually obvious as is a clear case of pulmonary embolism (PE). Other conditions can show up as defects in  the scan however, eg old PE or chronic obstructive airways disease (COAD). In some cases the scan can be indeterminate. A complex set of rules has been proposed for the interpretation of lung images, the PIOPED system.The system has not been verified with Kr81m images, but nevertheless has substantial relevance.









Home ] Reservoir System ] Model of Kr81m Admin. ] Tc99m Perfusion ] Standard Study ] Dual Energy Acq ] paediatrics ] Problem Patients ] Clinical Reporting ]

Last modified: November 29, 2002