PROBLEM TO BE SOLVED: To achieve leakage prevention of a radiation to a subject P side and radiography up to a base part of a breast 15 by extending a radiation irradiation region 13 up to the base part of the breast 15 of the subject P in a mammographic tomography apparatus comprising a gantry 2 having a front plate 7 on which a breast inlet/outlet 17 for putting the breast 15 into/out from a breast storage part 3 is opened, a radiation generation tube 8 and a radiation detector 11 oppositely provided with the breast storage part 3 held therebetween in the gantry 2, and a rotation drive part for rotating the radiation generation tube 8 and the radiation detector 11 at the same angular velocity around a rotation shaft D passing inside the breast storage part 3.SOLUTION: A mammographic tomography apparatus includes a collimator 12 which rotates in synchronization with the radiation generation tube 8 around the rotation shaft D between the breast storage part 3 and a radiation emission part 10, and a radiation shielding body 14 which covers the inner surface of the front plate 7 on the side of a rotation path of the radiation generation tube 8 with respect to a rotation path of the collimator 12. In the rotation path of the collimator 12, an end of the collimator 12 on a side facing the front plate 7 gets into the side of the front plate 7 with respect to the surface of the radiation shielding body 14.COPYRIGHT: (C)2015,JPO&INPIT【課題】乳房収納部3へ乳房15を入出するための乳房入出口17が開口した前面板7を有するガントリ2と、ガントリ2内に乳房収納部3を挟んで対向して設けられた放射線発生管8及び放射線検出器11と、乳房収納部3の内側を通る回転軸Dの周りに放射線発生管8及び放射線検出器11を同一角速度で回転させる回転駆動部とを有するマンモ断層撮影装置において、放射線の被検者P側への漏洩防止と、放射線照射領域13を被検者Pの乳房15の付根部まで及ぼすことによる乳房15の付根部までの放射線撮影とを両立可能とする。【解決手段】乳房収納部3と放射線放出部10の間で回転軸Dの周りを放射線発生管8と同期して回転するコリメータ12と、コリメータ12の回転経路よりも放射線発生管8の回転経路の側の前面板7の内面を覆う放射線遮蔽体14とを設け、コリメータ12の回転経路において、コリメータ12の前面板7と対向する側の端部が放射線遮蔽体14の表面より前面板7の側に入り込んだ構成とする。【選択図】図2
