The medical dry imaging films are an emerging type of non-destructive medical imaging. They have been used in a wide range of applications, especially for in vitro and in vivo image acquisition. There are three major types: medical thermal films, medical laser films, and medical inkjet films. The non-destructive imaging measures the latent heat of the materials exposed to infrared laser light or visible light, which is used to monitor temperature changes at a microscopic level during medical diagnosis. These films can also examine skin conditions, tissue pathology, and many other applications. The medical dry imaging films have been able to bypass destructive tests that used to be employed by conventional x-rays and other types of radiation. The medical dry imaging films are based on the same physical principle as thermal imaging cameras – the measurement of infrared radiation emitted by an object upon heating. Unlike thermal imaging cameras, however, these films measure only heat energy emitted from an object’s surface.

What are medical dry imaging films?

Medical dry imaging films are made up of reusable thermal recording paper or transient-type heat-sensitive paper; they are a convenient, effective, cost-efficient and safe method for diagnosing patients. They use the principles of measuring latent heat to record temperature changes at a microscopic level and provide a permanent, accurate, clear record. The medical dry imaging films have been used in medical research for more than 20 years. They are considered as an emerging type of non-destructive medical imaging because of their ability to capture microscopic images with high resolution. The currently available types include:

● Advanced medical thermal imaging film.

● Advanced medical laser imaging film.

● Advanced medical inkjet imaging film.

What are the different types of medical dry imaging films

● Medical thermal films

The medical thermal imaging film, also known as medical thermal record paper or temperature-sensitive paper, is a dry film that uses thermal radiation or infrared radiation to thermally record an object. This is the same technology used in thermal imagers (such as those manufactured by Pentax Medical, Olympus, and Fujifilm) for recording images at temperatures up to 150 °C.

Features of medical thermal films

Has a blue PET: The medical thermal film has a PET substrate color. It is more sensitive to infrared light than an ordinary thermal imaging film. Provides diagnostic information through the temperature changes recorded. The recording layers are stable in water, meaning they can be washed with water without degradation in quality.

Black and white color: the identifying marks are printed on the opposite side of the paper to those used in medical thermal imaging film, which healthcare professionals consider more acceptable.

Two years shelf life: clinical tests have proven that the medical thermal paper has a shelf life of two years.

No special equipment is required: unlike other types of thermal imaging films, the medical thermal imaging film does not require any dedicated equipment to be used. Unlike infrared imaging devices, the medical thermal imaging film can be used on standard radiography equipment (radiography devices). The images can be recorded directly on the patient for immediate diagnosis.

Advantages

Higher resolution: medical thermal imaging film has a 1,200 line/mm resolution. By comparison, ordinary thermal imaging film has a 200 to 300 line/mm resolution.

Faster processing speed: medical thermal imaging film has a processing speed of up to 3 seconds, 1 second faster than ordinary thermal imagers.

Are not sensitive to temperature changes: the medical thermal imaging film’s sensitivity is more stable when compared with thermal imaging that uses x-rays, radioactive substances and other technologies. The medical thermal imaging film is unaffected by temperature changes.

High stability: the medical thermal imaging paper is non-negotiable and is resistant to many test procedures used in radiology.

Disadvantages

1. The medical thermal imaging film is more expensive than ordinary thermal imaging film.

2. It is sensitive to room temperature (the medical thermal paper cannot perform the recording at low or high temperatures).

Applications

The medical thermal imaging film is used for clinical diagnosis, including:

● X-ray examination

● Ultrasound examination

● Radiotherapy treatment

● Therapeutic endoscopy

● Laparoscopy  surgery

● Echocardiography  examination

Medical thermal films are available in black and white. A black and white image of the abdomen can be produced by a black and white (B&W) contrast medium. A contrast medium is a material placed on the surface of a paper to make it appear more opaque or less transparent, allowing the passage of radiations that would not normally pass through the paper.

● Medical laser films

Medical laser imaging film is a type of dry film that uses infrared absorption to thermally record an object. The technology used in this film is similar to the laser thermal imaging camera in terms of its optical characteristics, which makes it possible to use the same instrumentation.

Features of medical laser films

Optical coherence tomography: is a non-invasive technique used to study the structure and dynamics of cells, tissues, and organs by measuring their thermal profiles and blood flow. The technique uses the absorption of light at different wavelengths to create images of the interstitial fluid (IIF) through the use of thermo optics.

Photoacoustic imaging: is a non-invasive optical imaging technique for in vivo tissue imaging based on the photoacoustic effect. It uses a laser to stimulate the microvasculature of tissue, and then the thermoelastic expansion of the tissue is recorded by an acoustic transducer.

Black and white thermal recording film: unlike ordinary thermal recording paper, which uses sodium chloride as an invisible ink to record information, this type of medical thermal paper employs molybdenum blue as its invisible ink.

Advantages of medical laser films

1. Laser light acupuncture: uses laser light to stimulate acupuncture points and induce a local reaction in the tissue, such as body temperature changes.

2. Acupuncture point therapy: uses laser light to stimulate acupuncture points to promote local blood flow, reduce pain and treat disease.

3. Medical imaging: uses laser-based thermal imaging for diagnosis at a cellular level and for monitoring the progress of tissue regeneration.

4. Photodynamic laser therapy: uses laser light to destroy cancer cells or toxic cells in the body.

Disadvantages of medical laser films

1. Expensive: medical laser medical imaging film is more expensive than ordinary thermal imaging film.

2. Limited applications: unlike ordinary thermal imaging, which can be applied in a wide range of non-medical fields, such as heat loss detection, long-range temperature measurement, etc., the medical thermal laser film’s applications are limited to a small number of clinical areas and cases.

Applications

Medical laser imaging films are used in the following fields of medicine:

Optical coherence tomography: is a non-invasive technique used to study the structure and dynamics of cells, tissues, and organs by measuring their thermal profiles and blood flow.

Photoacoustic imaging: is a non-invasive optical imaging technique for in vivo tissue imaging based on the photoacoustic effect.

● Medical inkjet films

Medical inkjet films are thermally printable films that use the thermal property of liquid ink to form images. They can store and record thermal data, representing clinical data in different forms, including X-ray images, ultrasound scans, and MRIs. The infrared imaging film is made using a special ink called Hyperdry® (marketed by Echurion Technology Inc., formerly by AT&T as Hypertherm) that dries quickly to avoid condensation and has no effect on the thermoacoustic properties of an object. This technology was invented by Professor Stephen Brierley from the University of Cambridge and applied for the first time in 1997 for imaging blood vessels under infrared illumination.

Features of Medical inkjet films

Great transmission density: has a high density of 0.3 to 0.5 mm/mil, which makes it possible to obtain faster and more accurate images.

High sharpness and low fog: high image sharpness and low image fog are guaranteed by the new technology. The image edge is sharp, which gives a spatial resolution of up to 0.02 mm/pixel.

Low temperature sensitivity and high resistance to abrasion: due to the good physical-chemical properties of the ink (durability, water absorption, etc.) used in this type of printing technology, it is possible to print on plastic materials used in automobiles and aircrafts without damaging these materials.

High stability across a wide range of temperatures: since it does not have a polymer or wax base as do other inks, the ink retains its optical properties at both high and low temperatures.

High durability: thermal inkjet films are made of paper material and do not contain glass when recording the image. This film type is also suitable for use with standard radiography equipment (radiography devices).

Environment friendly: this type of film contains no hazardous materials that pollute the environment.

Disadvantages of medical inkjet films

1. The ink is costly and requires a large amount of it to be made.

2. It cannot be used on certain types of paper (such as Bond Paper) due to its low adhesion on this particular paper type.

Applications

Black and white imaging: is used to record black and white images from medical scans such as X-rays, CT, MRI, and ultrasound. It can also be used to print blank forms like patient ID cards.

Color imaging: is used in the same fields as black and white imaging, but it can also be used in other fields such as the food industry or photography.

Conclusion

Before purchasing a dry medical film, it is important to carry out your research first. Each film has different features and applications. Knowing the different medical imaging films available, their features, and their applications can help you decide the best film type to use. With this, it is also possible to identify a medical imaging film that will suit your intended usage.