略語大辞典 [Med] 8 HVL half-value layer 半値層. 半値層厚. 放射線強度を半分に減衰させるアルミ金属媒質層の厚み.half-value layer; or half thickness; defined as the thickness of aluminum filtration required to cut the (radiation) beam intensity in half; the thickness of a layer which gives a half attenuator of radiation; in r 丸善「略語大辞典」JLogosID : 11877516