X-ray film types of X-ray film

Medical film belongs to a kind of silver salt photosensitive material, and its types can be summarized into the following four categories:

1. X-ray film for general photography

(1) Blue-sensitive film: Blue-sensitive film is a color-blind film used with blue-purple fluorescent intensifying screen, and its absorption spectrum peak is at 420nm. It is mainly divided into general-purpose (RX-type) films with standard sensitivity, suitable for most general photography, with moderate performance, low fog and high contrast, which can enhance the contrast among bones, air and contrast agents.

(2) Green-sensitive film (flat granular film): Green-sensitive film is a positive film used in conjunction with a green-emitting intensifying screen, and its absorption spectrum peaks at 550nm. It cuts three-dimensional silver halide particles into flat shapes and arranges them in the expected way, and adds a layer of dye to the emulsion to prevent the fluorescence overlapping effect, thus increasing the clarity of the image.

(3) Positive color film for breast photography: This is a special film for breast with high resolution, high contrast, single-layer emulsion and sensitivity to green light. Because of the flat particle technology, the fluorescence overlapping effect is almost reduced to 0%, and extremely clear and sharp images can be obtained, which can improve the skin line image, especially in breast enhancement photography.

(4) High-definition photographic film: This is a film with high resolution and high contrast. It is especially suitable for limb photography that requires providing high-definition images and displaying tissue microstructure information.

2. Imaging film of multiple cameras and laser cameras

(1) Multi-camera imaging film: This film is also called CRT image recording film. It is suitable for imaging records of various cameras such as CT, MR, DSA and ECT. The film is a single-sided emulsion (color separation), and the back is coated with an anti-halo layer to ensure the clarity and delicacy of the image and reduce the image blur caused by fluorescent substances.

(2) Imaging film of laser camera: It can be divided into He-Ne laser film (HN type) with absorption spectrum peak of 633nm and infrared laser film (IR) with absorption spectrum peak of 820nm. This film is characterized by extremely fine latex particles, single-layer coating and anti-halo coating on the back. The digital imaging quality of laser film is much higher than the analog imaging of multiple camera films.

3. Image enhanced recording film

(1) Fluorescent film: Due to the development of cardiovascular radiology, the requirements for fluorescent film imaging technology are more and more extensive and strict. Therefore, the corresponding film requires both high sensitivity and fine particles. According to different clinical uses, there are as many as five kinds of such films.

(2) Fluorescent screen image and fluorescent microfilm: This kind of film is suitable for aiming photography (spotting) under fluorescent screen or fluorescent microfilm during physical examination. One side of the latex is coated with an anti-blooming layer on the back, with specifications of 70mm, 90mm, 105mm and100x100mm respectively.

4. Special films

(1) Direct reversal film: It can be copied manually by ultraviolet light source or successfully by a special copier at one time, and the image with the same quality as the original X-ray photograph can be obtained. The photosensitive characteristics of single-layer emulsion and blue polyester film base are just the opposite to the original film, which is an inverted characteristic curve, and the unexposed part is completely black.

(2) Cleaning film: This is the drum cleaning film of the automatic developing machine. After turning on the automatic washing machine every morning, you should use 3-4 sheets of cleaning paper to clean the washing machine overnight.

5. Preservation of film

The maintenance of the original photographic performance of the film has a great relationship with its surrounding conditions. Unexposed films should be stored as "biological products".

(1) Standard storage conditions: temperature 10 ~ 15℃, humidity 40 ~ 60%; Prevent radiation exposure; X-rays must be completely away from radiation, which will cause serious fog on the film.

(2) Preventing pressure effect: The pressure effect will produce artificial artifacts, which is also the reason why the film box is placed upright.

(3) Avoid contact with harmful gases: The film should avoid contact with harmful gases, such as formalin, engine exhaust, gas, etc. Otherwise the film will be foggy.

(4) Refrigeration of membrane: The refrigerated membrane should be taken out 24~36 hours before use and balanced at room temperature. Otherwise, there will be photosensitive delay. Especially don't unseal it in the cold storage.

(5) Validity period: The film packaging indicates the validity period, which refers to the validity period under standard storage conditions. If the storage conditions deteriorate, the quality will decline even within the validity period. The validity period is generally determined as 18 months after the factory date.