Chest x-rays, how people stand. Relationship between face and x-ray. X-ray from face to back?

The "X-ray positive film" you mentioned is called "chest positive film" in medical vocabulary, and there are left and right positions and left and right oblique positions of the chest. Let's talk about the instrument sub-tube (the device that emits X-rays) and the intensifying screen (the sensing device that receives X-rays and images) when taking chest radiographs. Among them, the chest radiograph is also divided into anteroposterior position and posteroanterior position. The anteroposterior position is that the back is facing the sensitizing screen, facing the tube (that is, facing the X-ray), the upper limbs rotate inward, the palms are close to the upper edge of the buttocks (medically called the anterior superior iliac spine), and the chest film is taken after inhaling and holding the breath. This situation is mostly used for patients who can't stand. Generally, they are photographed by bedside X-ray machine in front of the hospital bed, so the patients are all facing up. The other is the front and back position. The patient stands naturally, facing the enhanced screen (with his back facing the X-ray), with his chest close to the enhanced screen, his upper limbs turned inward, and his palms close to the upper edge of his hips (in fact, the purpose of this action is to make the upper limbs move away from the shoulder blades, so that the images of the lungs can be displayed completely without being affected by the shoulder blades), and then he takes a breath and holds his breath to be exposed. Very good! Specifically, you can search for "chest X-ray" in Baidu Library, and it is better to consult the radiology department of a nearby hospital. I'm sure our colleagues will inform you.