Some tumors are located close to radiation-sensitive organs and structures, known in radiation oncology as organs at risk, or OARs.

Examples include the brain, spinal cord, optic nerves, eyes, salivary glands, heart, lungs, bowel, kidneys, bladder, rectum, and major blood vessels.

When a tumor lies near these structures, treatment planning must deliver an effective dose to the tumor while limiting radiation exposure to nearby normal tissues. Particle therapy may be considered because it can concentrate the dose on the tumor while reducing radiation to adjacent critical structures.

Hospital review considers the cancer type and stage, tumor size and location, proximity to organs at risk, prior treatment, recent imaging, and the patient’s general condition.

Recent CT, MRI, or PET-CT images in DICOM format are usually needed to assess whether particle therapy can be planned safely and effectively.

APIS coordinates record submission and communication with relevant Korean hospitals for international patients seeking particle therapy.