The DRT4 system is our flagship laser Doppler monitor and is suitable for any laser Doppler monitoring application. The key features of the DRT4 lend itself particularly well to more advanced research and clinical uses where dedicated software and hardware simplifies routine stimulation protocols and data collection. Typical applications are described below but this list is far from exhaustive. Please use the PubMed Search (right) to discover the latest research in your field or contact us (in confidence) to discuss any new research ideas you might have.

Allergies - The nasal muscosa and skin are two sites particularly exposed to allergic reaction. Standard skin probes and imaging are appropriate for assessing perfusion of the skin. The situation for assessing the nasal mucosa is more complex: choice of site and type of probe are important considerations. The septum is inappropriate as contact with a probe evokes pain and sneezing. The preferred site is the anterior tip of the inferior turbinate mucosa. Endoscopic probes are particularly appropriate because of the rounded tip although needle probes may be considered when a probe stabilisation device is used (e.g. attached to headphones or an American football helmet if a stereotactic holder is not available).

Cerebral Blood Flow - Laser Doppler assessment of cerebral blood flow is used in conjunction with other techniques for multi modal monitoring of head injured patients. Failure of autoregulation at intercranial pressures (ICP) of less than 58mmHg were noted by Kirkpatrick et al (1994) and CO2 evoked responses have been described by Bolognese et al (1995). These assessments have been made using invasive procedures but non-invasive blood flow assessments have also been performed using skin probes on the forehead and the gross changes at brain death recorded (Litscher et al, 1995).

Gastroenterology - Endoscopic probes can be used in conjunction with gastroscopes or NG tubes to assess flow of the gastric mucosa and disorders. This can be used as a predictor of non-healing of benign gastric ulcers (Clarke et al, 2002) or to measure the effect of treatment intervention on mucosal flow.

Pharmacology - The effects of topical or systemic vasoactive drugs on human tissue blood flow can be assessed by laser Doppler allowing dose response measurements to be made. Iontophoresis [0] can be used to deliver ionic drug solutions and the dedicated drug chambers allow the flow response to be measured at the site of delivery.

Tooth Vitality Testing - Cardiac cycle blood flow pulsation in the supplying artery are transmitted to the pulp capillaries as pulsations in blood velocity. These pulsations are apparent on laser Doppler monitor traces of vital teeth and are absent from non-vital teeth. The mean blood flux level in healthy teeth is much higher than for non-vital teeth. However in vital teeth with impaired blood supply the flux level can be low and the presence of pulsation is the only indication of vitality.