Radioisotopes often emit alpha particles, beta particles, or gamma rays. the distance they travel through matter increases in order from alpha to gamma. each radioisotope has a characteristic half-life, which is the time needed for half of a sample of radioisotope to undergo nuclear decay. which quality is desirable for a radioisotope that is used for medical imaging of a specific organ? check all that apply. half-life of several years half-life of several days half-life of several seconds emission of gamma rays emission of alpha particles ability to be attached to a compound used by the body ability to pass through the body without being absorbed