Roof unshielded high kv photography system

The horizontal distance (not less than 10m) between the outer surface of the carriage and the lighting window of the building where people work or live should be considered when the high kV photographic system with unshielded roof works.

High-kV photography refers to the technology of photographic detection by using X-rays generated above 100 kV (100- 125 kV). Generally, the voltage used in X-ray photography is between 45 and 90 kV, and the absorption of X-rays by human body is mainly based on photoelectric effect. The development density of various structures is greatly influenced by the atomic number and thickness of tissues.

In particular, soft tissue, fat, gas and bone overlap on a plane, and their images are all covered by high-density bone images, which cannot be clearly displayed. Due to the uneven penetration of photoelectric effect into human body, the absorption difference between ribs and soft tissues increases, but the contrast is high and the number of layers is small.

When the voltage is higher than 100kV, the tissue absorption is dominated by scattering effect, which is less affected by atomic number and thickness. It depends on the weight of the material per unit volume, but is only affected by the density of the material, so the absorption difference between bone and soft tissue is reduced, and the image is not covered by bone, so the contrast is reduced and the image level is rich.

At present, most hospitals have applied digital X-ray chest high kV photography technology. High-pressure chest radiograph is not only effective for observing various masses in lung and mediastinum, but also suitable for X-ray examination of various small lesions, pulmonary fine nodules, interstitial fibrosis, infiltrative lesions and pneumoconiosis.