English to Russian Medical Medical: Instruments multimodal X-ray equipment

Я выполняю proof описания цифрового радиологического аппарата. Переводчик предложил перевести shutter как *маска*. Я считаю это неправильным термином.

Примеры :

Shutters
• Shutters can only be applied to X-ray images.
• Shutter movements apply to the images in the view, depending on the propagation setting: All, Single, Following or Preceding.
You can apply shutters to an image (horizontal, vertical, circular or a combination thereof ).


Select overlay
There are two ways to project target views on the source views:
• Shutter overlay.
• Color overlay.
Shutter overlay
The shutter method projects each target view partly on its corresponding source view. You can slide the boundary in each view to have the preferred parts of the source and target views visible.

Merge by shutters
Merge the source images by applying a shutter. The shutter defines which part of the second source is overlaid on the first.