title: Effective and organ doses using helical 4DCT for thoracic and abdominal therapies.
abstract: The capacity of 4DCT to quantify organ motion is beyond conventional 3DCT capability. Local control could be improved. However we are unaware of any reports of organ dose measurements for helical 4DCT imaging. We therefore quantified the radiation doses for helical 4DCT imaging. Organ and tissue dose was measured for thoracic and abdominal 4DCT in helical mode using an adult anthropomorphic phantom. Radiation doses were measured with thermoluminescence dosimeter chips inserted at various anatomical sites on the phantom. For the helical thoracic 4DCT, organ doses were 57.2 mGy for the lung, 76.7 mGy for the thyroids, 48.1 mGy for the breasts, and 10.86 mGy for the colon. The effective doses for male and female phantoms were very similar, with a mean value of 33.1 mSv. For abdominal 4DCT imaging, organ doses were 14.4 mGy for the lung, 0.78 mGy for the thyroids, 9.83 mGy for breasts, and 58.2 mGy for the colon (all obtained by using ICRP 103). We quantified the radiation exposure for thoracic and abdominal helical 4DCT. The doses for helical 4DCT were approximately 1.5 times higher than those for cine 4DCT, however the stepwise image artifact was reduced. 4DCT imaging should be performed with care in order to minimize radiation exposure, but the advantages of 4DCT imaging mandates its incorporation into routine treatment protocols.
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Matsuzaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Fujii
authors.forename: Motoki
authors.initials: M
authors.lastname: Kumagai
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsuruoka
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Mori
mesh_terms: D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000295:instrumentation / Q000379:methods; D013902:Radiography, Thoracic / Q000295:instrumentation / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods; D012680:Sensitivity and Specificity; D013899:Thoracic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*; D014781:Viscera / Q000000981:diagnostic imaging
keywords: 4DCT; cine; effective dose; helical; radiation dose