The source-skin distance of image intensifier equipment should not be less than _____ cm.

The minimum source-skin distance (SSD) requirement for image intensifier equipment is established primarily to ensure patient safety and to minimize radiation exposure. According to regulations and best practices in radiology, maintaining an SSD of at least 38 cm helps to reduce the entrance dose by maximizing the distance between the radiation source and the patient's skin.

This distance plays a crucial role in limiting the intensity of scattered radiation reaching the skin, thereby lowering the risk of radiation burns and other detrimental effects. Furthermore, ensuring compliance with this distance standard is also part of achieving optimal image quality, as an adequate SSD helps to enhance the clarity of the images captured for diagnostic purposes.

The options presenting varying distances reflect different regulatory thresholds and technological considerations. However, 38 cm is widely accepted as a safe and effective minimum distance that balances the needs for adequate imaging while protecting patient health.