title: Washout measurement of radioisotope implanted by radioactive beams in the rabbit.
abstract: Washout of 10C and 11C implanted by radioactive beams in brain and thigh muscle of rabbits was studied. The biological washout effect in a living body is important in the range verification system or three-dimensional volume imaging in heavy ion therapy. Positron emitter beams were implanted in the rabbit and the annihilation gamma-rays were measured by an in situ positron camera which consisted of a pair of scintillation cameras set on either side of the target. The ROI (region of interest) was set as a two-dimensional position distribution and the time-activity curve of the ROI was measured. Experiments were done under two conditions: live and dead. By comparing the two sets of measurement data, it was deduced that there are at least three components in the washout process. Time-activity curves of both brain and thigh muscle were clearly explained by the three-component model analysis. The three components ratios (and washout half-lives) were 35% (2.0 s), 30% (140 s) and 35% (10 191 s) for brain and 30% (10 s), 19% (195 s) and 52% (3175 s) for thigh muscle. The washout effect must be taken into account for the verification of treatment plans by means of positron camera measurements.
authors.affiliation: Department of Quantum Science and Energy Engineering, Tohoku University Graduate School of Engineering, Aoba-yama-4, Sendai 980-8579, Japan. mizuno@cancer-c.pref.saitama.jp
authors.forename: H
authors.initials: H
authors.lastname: Mizuno
authors.forename: T
authors.initials: T
authors.lastname: Tomitani
authors.forename: M
authors.initials: M
authors.lastname: Kanazawa
authors.forename: A
authors.initials: A
authors.lastname: Kitagawa
authors.forename: J
authors.initials: J
authors.lastname: Pawelke
authors.forename: Y
authors.initials: Y
authors.lastname: Iseki
authors.forename: E
authors.initials: E
authors.lastname: Urakabe
authors.forename: M
authors.initials: M
authors.lastname: Suda
authors.forename: A
authors.initials: A
authors.lastname: Kawano
authors.forename: R
authors.initials: R
authors.lastname: Iritani
authors.forename: S
authors.initials: S
authors.lastname: Matsushita
authors.forename: T
authors.initials: T
authors.lastname: Inaniwa
authors.forename: T
authors.initials: T
authors.lastname: Nishio
authors.forename: S
authors.initials: S
authors.lastname: Furukawa
authors.forename: K
authors.initials: K
authors.lastname: Ando
authors.forename: Y K
authors.initials: YK
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Kanai
authors.forename: K
authors.initials: K
authors.lastname: Ishii
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002250:Carbon Radioisotopes / Q000378:metabolism*; D003198:Computer Simulation; D006207:Half-Life; D018499:Linear Energy Transfer / Q000502:physiology*; D008657:Metabolic Clearance Rate / Q000502:physiology; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000378:metabolism*; D011180:Postmortem Changes; D011817:Rabbits; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*
chemical_list: D002250:Carbon Radioisotopes