Development of lung and soft tissue substitutes for photons

肺及び軟組織等価材の開発

木名瀬 栄   ; 木村 雅哉*; 野口 宏; 横山 須美

Kinase, Sakae; Kimura, Masaya*; Noguchi, Hiroshi; Yokoyama, Sumi

著者らは、これまで人体の骨格について密度や線減弱係数が等価な骨格組織等価材を開発するとともに頭部ファントムを製作した。本研究では、 さらに、 呼吸気道部等を表現するのに必要な人体の肺,軟組織,筋肉,筋肉+10パーセント脂肪,軟骨,喉頭,気管,甲状腺,腎臓,肝臓,皮膚,脳について、それぞれの組織等価材を開発した。また、それぞれの組織等価材は、実測により光子減弱特性を評価した。

We have developed polyurethane-based tissue substitutes simulating lung, soft tissue, muscle, muscle-adipose mixture tissue, cartilage, brain, larynx, trachea, thyroid, kidney, liver and skin. The formulation of the tissue substitutes for photons was based on the basic data method together with an equation for calculating the optimum relative mass of corrective additives. The tissue substitutes were formulated to be phantom materials in the photon energy range of at least 10 keV-10 MeV. In particular, they were designed to match the tissues with linear attenuation coefficients for low photon energy (13.6, 17.2 and 20.2 keV from Pu) and to have the same mass densities as the tissues. The tissue substitutes developed in the present study were examined for the photon transmissions using 16.6 keV KX-rays from Nb. The experimental transmission curves of the substitutes were found to be in good agreement with those derived from data on the tissues in ICRP Publication 23. It was found that the tissue substitutes are suitable as the corresponding tissues defined in ICRP.