Roper Industries Inc. of Duluth, Ga., has acquired Medtec Inc. for $150 million in cash. The Orange City, Iowa, company designs, develops and distributes technologies for the diagnosis and treatment of cancer. Its products include patient positioning devices, image-guided therapy software, and related items and accessories.The company will join the medical division of Roper’s imaging segment, which includes Civco Medical Instruments Co. Inc. of Kalona, Iowa, acquired in June. Medtec’s sales force, manufacturing capability and software engineering expertise are expected to benefit Civco and enable other acquisitions.