Dose evaluation and effective dose estimation from multi detector CT.
Computed tomography (CT) has evolved remarkably through device improvement and advancement of peripherals, including computers. In 1999, multi detector-row CT (MDCT) appeared and rapid high-speed scanning became possible. However, usefulness of MDCT in actual clinical application cannot be assessed until the exposure doses are assessed appropriately. Since CT examinations need a comparatively high dose, it is necessary to evaluate patient exposure for introduction of MDCT. Patient doses by three types of MDCTs were evaluated for cases of scanning of the chest and abdomen-pelvis. The examination conditions were the same as those in actual clinical examinations. The obtained effective doses were 9.4-28 mSv for the chest examination and 13-28 mSv for the abdomen-pelvis. The average surface doses varied between 16-43 mGy for the chest examination and 20-37 mGy for the abdomen-pelvis. The highest surface dose was 57 mGy for the abdomen-pelvis examination. The exposed doses differed according to scanning method and imaging conditions such as tube current, slice thickness and so on. It seemed that there is room for dose reduction by proper adjustment of scan conditions in MDCT examinations.
Nishizawa
Kanae
K
Department of Medical Physics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. nisizawa@nirs.go.jp
Matsumoto
Masaki
M
Iwai
Kazuo
K
Tonari
Ayako
A
Yoshida
Takashi
T
Takayama
Makoto
M
D006801:Humans; D008953:Models, Anatomic; D010388:Pelvis / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011860:Radiography, Abdominal; D013902:Radiography, Thoracic; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods