Guided imagery is defined as a technique of relaxation and pain control in which a person conjures up a picture that is held in mind during a painful or stressful experience. It is the intentional visualization of images that are calming, relaxing, or beneficial in other ways. Guided imagery, moreover, is an alternative medicine technique in which patients use their imagination to visualize improved health, or to "attack" a disease, such as a tumor. Some studies indicate that the positive thinking can have an effect on disease outcome, so this technique is now utilized as "complimentary medicine" in some Oncology centers and other medical facilities.