A £1.7 million investment in new digital X-ray equipment has been announced.
Funded by Welsh Government, Powys Teaching Health Board will implement the equipment to produce faster, clearer images.
This is expected to improve diagnostics and reduce waiting times for the people of Powys.
The first phase of the installation will begin on November 12 at Ystradgynlais, Llandrindod Wells, and Welshpool.
Claire Madsen, executive director for allied health professionals and health Sciences at Powys Teaching Health Board, said: "We thank you for your patience while we carry out these upgrades.
"Replacing the X-ray equipment at each site will take approximately eight weeks.
"During this time, we will need to close the X-ray departments in Ystradgynlais, Llandrindod Wells, and Welshpool and offer you an appointment at another of our community hospitals."
Ms Madsen assured that other radiology services such as ultrasound will remain unaffected.
The second phase of the X-ray equipment replacement is scheduled for early January.
Ms Madsen continued: "If you are referred for an X-ray by a GP or other healthcare professional whilst this work takes place, then our booking team will contact you to arrange an appointment in the nearest alternative location.
"If you have a minor injury, then we continue to encourage you to phone first for clinical advice.
"Our clinical team will be able to provide advice over the phone to help you access the treatment you need."
In addition to improved quality and speed, the new X-ray machines use a lower dose of radiation than the existing ones, reducing radiation exposure for patients.
The upgrades aim to improve access to treatment and the overall health service experience for the residents of Powys.
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