Tissue blood flow and temperature monitoring

  • We have found Moor equipment to be extremely dependable and innovative.

    Dean L. Kellogg, Jr., MD, Ph.D
    University of Texas Health Science Center

  • We can't recommend Moor instruments highly enough. The technology is at the cutting edge and the support second to none.

    Paul Sumners, PhD
    London South Bank University

  • It goes without saying that the company's imaging technology itself is superb!

    Gourav Banerjee
    Leeds Beckett University

  • In a nutshell, moorFLPI-2 is the most user-friendly system for studying cerebral blood flow regulation in rodents.

    Chia-Yi (Alex) Kuan, MD, PhD
    Emory University School of Medicine

  • Moor Instruments have consistently provided excellent help and support for my research.

    Kim Gooding, PhD
    University of Exeter Medical School

  • Laser Doppler Imager is a standard accurate method we now use in our cerebral blood flow and brain perfusion in our laboratory.

    Momoh A. Yakubu, PhD
    Texas Southern University

  • I cannot rate the company or the staff highly enough.

    Jim House, PhD
    University of Portsmouth

  • I expect to be using Moor Instrument’s technology for many years to come!

    Faisel Khan, PhD
    Ninewells Hospital & Medical School

This system has now been superseded by the moorVMS-LDF, for full details please click here.

The DRT4 was designed specifically for advanced clinical and research applications. The system offered many unique features to aid and simplify the measurement task including:-

  • Large graphical display
  • On-board data memory
  • Review and analysis functions on board
  • Full PC connectivity with powerful, in-house programmed Windows based PC software
  • Software to automate measurements involving skin heating, iontophoresis and pressure cuff provocations
  • Software for Plastic Surgery/Flap Monitoring Applications
  • Ability to collect analogue signals from up to four other devices (e.g. TCPO2, Dissolved Oxygenation etc)
  • Wide range of optic probes, some with temperature measurement to allow assessments from almost any tissue

We can offer full support for this product including service, software and a range of probes to assess almost any tissue type.

This system has now been superseded by the moorVMS-LDF, for full details please click here.

The following products are AVAILABLE TO BUY ONLINE and work with the DRT4

This system has now been superseded by the moorVMS-LDF, for full details please click here.

This section lists the more common questions our customers have about the DRT4 system. If you have a question you would like answered that does not appear below then please email us. We are happy to help!

Q. Can data be sent between the DRT4 and a PC for storage, further analysis etc?
A. Yes, this is easily done via the Serial or USB ports of the PC, using our dedicated Windows software package (moorSOFT). Data transfer can be 'live' - i.e. at the time of measurement or after the measurement by downloading from the DRT4 memory. Where conditions and space allow we recommend live monitoring as the safest form of data capture.

Q. How long is the stored data safe in the DRT4 without connecting it to the electrical supply?
A. We would always recommend downloading data as soon as practically possible to safeguard your measurement. However your data is safe for at least eighteen months (new DRT4) - as the data is saved by an internal battery. As the DRT4 gets older, or the battery weaker this 'safe' time is reduced.

Q. How often should the probes be calibrated?
A. We have some customers who calibrate daily and others less regularly. The important thing to bear in mind is that the room temperature should be close to the same each time you calibrate. There is a risk of 'over calibration' - excessive calibration throughout the day - which can be counterproductive if there are large temperature swings. This can result in changes in the Brownian motion of the polystyrene microspheres. We would normally recommend calibrating at least weekly during the course of a scientific investigation. Calibration is also a good indicator of probe condition. A damaged probe will not calibrate!

Q. Can I measure other signals at the same time as flux and temperature?
A. Yes, the DRT4 has 4 analogue input channels. Signals of 0-10 volts can be monitored via the AN02 (AN01 for DRT4 serial Nos 3000 - 3124) interface and transferred live from the DRT4 (research software) to PC with moorSOFT/DRT4 PC software!

Q. Should the skin be cleaned before measurements?
A. Yes - we recommend using an alcohol wipe. Dry or flaky skin can be removed with sticky tape.

This system has now been superseded by the moorVMS-LDF, for full details please click here.

The list below contains a selection of references citing use of DRT4. The list below is a small selection. Please contact us for reference lists on your chosen subject.

Minson CT, Holowatz LA, Wong BJ, Kenney WL, Wilkins BW.
Decreased nitric oxide- and axon reflex-mediated cutaneous vasodilation with age during local heating.
J Appl Physiol; 2002 Nov; 5 (93):1644-9

Timar-Banu O, Beauregard H, Tousignant J, Lassonde M, Harris P, Viau G, Vachon L, Levy E, Abribat T,
Development of noninvasive and quantitative methodologies for the assessment of chronic ulcers and scars in humans.
Wound Repair Regen; 2 (9):123-32

Wilder-Smith E, Wilder-Smith A, Egger M,
Peripheral autonomic nerve dysfunction in asymptomatic leprosy contacts.
J Neurol Sci; 1997 Sep; 1 (150):33-8

Mesaros S, Trope M, Maixner W, Burkes EJ,
Comparison of two laser Doppler systems on the measurement of blood flow of premolar teeth under different pulpal conditions.
Int Endod J; 1997 May; 3 (30):167-74/

This system has now been superseded by the moorVMS-LDF, for full details please click here.

Moor Instruments are committed to product development. We reserve the right to change the specifications below without notice.


Laser Safety Classification Class 1M per IEC 60825-1:2001
Class 1 (per 21 CFR 1040.10 and 1040.11)
Output power 2.5mW max.
Wavelength 785nm ± 10nm
Angular spread of laser light from probe tip 28° ± 5°
All specifications include cumulative measurement uncertainties and expected increases in values after manufacture


Range 5-50°C
Resolution 0.1°C, accuracy ± 0.3°C
Patient isolation (per IEC 601-1 Class 1 type BF)


Bandwidth: high pass 20Hz
Low pass selectable 3KHz, 15KHz, 22KHz
Output time constants: 0.02s, 0.1s, 0.5s, 1.0s, 3.0s
Automatic gain control and zeroing


Graphical/digital LCD screen display
40Hz maximum data display rate to 1/min minimum display rate
0-1000 arbitrary perfusion units, percentage change
2 serial interface RS232 (1 optically isolated)
Analogue outputs 0-10V D/A 12 bit 4 channel (external bus)
Analogue inputs 0-2.5V A/D 10 bit 4 channel (external bus) Serial Numbers up to and including 3124
Analogue inputs 0-10V A/D 12 bit 4 channel Serial Number 3125 and above


Flash memory programmable from PC
Alarm levels and event markers
Trends – data review and time scale compression
500Kbyte battery backed memory
Percentage change and areas
Mean, maximum, minimum values.
Calibration – storage of probe scaling constants


Universal voltage switch-mode power supply
range 100 to 230V at 55VA, 50 to 60Hz
Dimensions W H D mm 280 x 160 x 360
Weight 7kgs


Temperature 0-45°C
Humidity 0-80% RH
Atmospheric pressure 500 – 1060hPa
Operating temperature 15-30°C


Electrical safety standards IEC 601-1:
Type of protection against electric shock: Class 1
Degree of protection against electric shock: Type BF
Degree of protection against ingress of liquid: IPXO (not protected)
Degree of protection against flammable anaesthetics – Equipment not suitable for use in the presence of a flammable anaesthetic mixture with air or with oxygen or with nitrous oxide.
Mode of operation – continuous.


Accuracy: ± 10%, relative to Moor Instruments ‘standard’ DRT4
Precision: ± 3% of measured value
Range: 0-1000 AU

Accuracy: ± 10%
Precision: ± 5%
Range: 0-1000 AU

Accuracy: ± 10%
Precision: ± 3%
Range: 0-255 AU

This system has now been superseded by the moorVMS-LDF, for full details please click here.

Moor Instruments manufacture a wide range of probes designed to help you assess flow from almost any tissue. We are more than happy to advise on your particular application but hope too that the following general notes are useful.

Skin probes are available with two main fibre configurations, twin or multi-fibre designs. Multi-fibre designs usually contain a ring of up to eight collecting fibres around a central delivery fibre. This provides an averaged signal for a larger tissue area than would otherwise be provided by the conventional twin fibre model.

Skin probes are usually fixed to the skin with a probe holder and double sided adhesive discs, although they can be used in other applications (e.g. bone, visceral measurements) and with other equipment (e.g. Iontophoresis). Please refer to the Accessories and Iontophoresis catalogues. DRT4 users can specify combined laser Doppler and temperature probes.

The standard length for all probes is 2 metres. Longer lengths can be supplied on request (code PXL). The range of probe holders for these (and other) probes is described in the accessories page.

Needle probes are amongst the most versatile designs. They can be used for surface measurements, inserted into tissue or used for single vessel measurements. The compact design also lends itself to measurements in tissues with restricted access, e.g. teeth, conjunctiva and where micromanipulation is required.

Probes can be fixed in position over tissue with a normal laboratory manipulator by clamping onto the black acetal shank.

Deeper measurements are possible by inserting the probe tip into tissue bulk, for which finer needles are suitable (VP4 and VP4s). The finest needles can be inserted directly into some tissues with the application of gentle pressure: for larger needles it may be necessary to puncture the tissue first with a hypodermic needle.

The use of specific probe holders can extend the application range of needle probes further still. Wet stick probe tips can be used to aid adhesion to moist/ mucosal surfaces. Dental putty can be used to create an individual probe holder for tooth measurement. Angled needle probes can be used to access hind teeth.

Although laser Doppler is not usually advocated for assessment of flow in single vessels, there is a role for the technique in the assessment of flow changes in small individual vessels. Moor manufactures a range of probe holders to aid this measurement.

Endoscopic probes enable internal investigations of blood flow in tissue beds such as colon, bronchus and urethra. The probes are available in a wide range of diameters to fit the biopsy channel of most endoscopes. All are made from a flexible yet tough nylon sleeving.

The finer diameter probes, although generally more delicate, can be used with some naso-gastric tubes: the tip of the n.g. tube is removed to allow an end viewing probe to protrude for measurement.

The standard length for all endoscopic probes is three metres. Longer lengths can be supplied, to a maximum of 4 metres, and are particularly useful for larger animals (e.g. horses).

Low profile designs are either used where access is difficult (e.g. oral mucosa) or to reduce application pressure if the probe is to be covered by bandages. Various designs are available, including the titanium disc probe and the near flat silicon probe.

VP10M100ST & VP10M200ST Master/ single fibre probe system. Master probes are twin fibre designs, acting as a link between the monitor and the single fibre probe. The Master probe connects to the single fibre probe via an optical in-line connector (order code PCP).

This system offers a number of advantages over more conventional probe designs. The benefits include;

1. Small diameter probes (down to 250micron) for minimally invasive measurements.

2. Wide choice of single fibre probes for diverse measurements. Just connect a new probe for a change to muscle, cerebral, gastric, organ or endoscopic (etc.) applications. This represents an economic solution if you intend to sample at a number of different tissue sites with a limited number of LDF channels.

3. Single fibre probes are supplied with re-usable, detachable connectors (order code PCN). Probes can be sterilised easily for re-use or treated as disposable (see P10d, P10k,P10s-TCG). Moor Instruments can also supply the materials for you to construct your own single fibre probes.

4. For longer-term measurements the Master can be disconnected to leave the single fibre in position between measurement periods.