Amends the Illinois Insurance Code. Provides that an individual or group policy of accident and health insurance or a managed care plan that is amended, delivered, issued, or renewed on or after January 1, 2026 shall provide coverage for molecular breast imaging (MBI) of an entire breast or breasts if a mammogram demonstrates heterogeneous or dense breast tissue or when medically necessary as determined by a physician licensed to practice medicine in all of its branches. Amends the Health Maintenance Organization Act. Subjects health maintenance organizations to provisions of the Illinois Insurance Code that require coverage for mammograms, mastectomies and certain other breast cancer screenings. Amends the Counties Code, the Illinois Municipal Code, and the Health Maintenance Organization Act. In provisions concerning coverage for mammograms, provides that coverage for certain types of mammography shall be made available to patients of a specified age.