A Mobile Single-Photon Emission Tomograph for Brain Death Detection and Evaluation of Scull-Trauma Severity at Mass Disasters and Car Accidents
Tech Area / Field
- MED-DID/Diagnostics & Devices/Medicine
- INS-DET/Detection Devices/Instrumentation
3 Approved without Funding
NIIIT (Pulse Techniques), Russia, Moscow
- VNIIIMT (Medical Engineering), Russia, Moscow
- Hôpital Saint-Antoine, France, Paris
Project summaryThe aim of the Project is the design and development of a Mobile Single-Photon Emission Tomograph for brain death detection and evaluation of scull trauma severity at mass disasters and car accidents.
At mass disasters (earthquakes and the like) as well as at accidents of various kinds scull traumas are among the leading causes of people deaths. It is very important for the physicians to evaluate promptly and adequately the severity of scull traumas of the injured to take them to proper medical institutions and give them better chance for survival.
It is important also from the point of view of transplantology, since young and healthy people having scull traumas resulting in coma and brain death are the main contingency of donors for transplantation of their hearts, kidneys, lungs and liver.
Although modern reanimatology permits support of the life of a patient with dead brain for rather a long period of time, degradation of the quality of all of his organs occurs and chances for a successful transplantation become low.
The existing diagnostic methods (such as Glasgo scope or electroencephalography) are non-objective and non-specific, and a group of neurologists who must make a verdict of death usually delay making the decision.
Recent publications describe an objective and sensitive method of brain death detection. Such is Single-Photon Emission Computer Tomography (SPECT) of brain with lipophilic amines labeled by Tc-99m or J-123.
The essence of the method is in that lipophylic amines (amphetamine J-123 and HM-PAO-Tc-99m) are injected intravenously and on arriving into brain capillaries pass through hematoencephalic barrier and penetrate into nerve cells. They cannot leave the cells because of PH-shift and stay there for some days. So the amount of labeled amines in some part of a brain is proportional to the capillary blood flow in that part, i.e. the brain perfusion.
By applying SPECT one can obtain "slices" of radioactivity all over the brain, i.e. visualize the brain perfusion distribution. It is easy to differentiate the radioactivity inside the brain and the activity in soft tissues outside the brain in SPECT images and to detect deterioration or absence of perfusion.
Practical use of such tomographs is limited due to the fact that they are stationary and need the patient to be transported to the hospital where they are located. In cases of mass severe traumas, as at an earthquake, for example, transportation becomes a serious problem.
It is obvious that a mobile SPECT is required which could be transported inside a hospital and around a town or to the site of a catastrophe in an ambulance car.
The purpose of the Project is to design and develop such a tomograph for examining and diagnosing patients with scull traumas in hospitals as well as at the sites of catastrophes or accidents. It is supposed to have high enough sensitivity so that the whole set of diagnostic procedures could be performed in 30 min at administrated activity of 20 mK. In designing the instrument one of the purposes is simplifying the examination procedure and making it more comfortable for a patient. All the diagnostic data collection and processing will be PC controlled.
In carrying out of the Project position sensitive detectors, key components of the SPECT, will be designed on the basis of photomuitipiiers with square photocathodes, its mechanical part will be designed and manufactured and a proper data collection and processing system developed. The principal direction of work will be defined on the basis of through studying of all the publications on the subject, including patents.
ARMERI has good experience in designing linear position sensitive detectors, which can be used as prototypes for a mobile SPECT. RIPT specialists who are responsible for major part of the activities within the Project have a number of achievements in designing photoeiectronic devices and moving mechanisms, so using their experience for purely civil medical purposes addresses the ISTC objectives.
The Project is supposed to be realized using the method of brain death detection by radionuclide visualization of brain blood flow.
The essence of the method is in that lipophilic amines (such as amphetamine J-123 and HM-PAO-Tc-99m), injected intravenously, are able to pass through the hematoenthephalic barrier of brain nerve cells and stay in them.
Single-photon tomography allows to obtain "slices" of radioactivity distribution in the brain, i.e. to visualize the brain perfusion distribution. Although the last one can be obtained using conventional planar gamma-cameras as well, diagnostic uncertainty increases in this case due to radiation from soft structures of the head.
In tomographic images is easy to differentiate the accumulation of radioactivity in the brain and in the soft tissues, as well as to detect areas with deteriorated or null blood flow.
ARMERI has good experience in designing linear position-sensitive detectors, and such a detector can be looked upon as a prototype for designing a mobile single photon emission tomograph.
Theoretical investigations are based on thorough studying of all the publications on the theme, including patents.
Once the principal direction of work is chosen, the major functional units of the tomograph will be designed:
- the position-sensitive detector;
- the mechanical part (the moving mechanism, the bed for the examination of a patient's head);
- the data collection and processing system.
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