Patent Number: 
Section: claims

1. A radiation imaging apparatus comprising:a detection unit for detecting a radiation distribution transmitted through an object;an imaging unit which includes said detection unit; anda grid for suppressing scattered light which is detachably mounted on an outside of said imaging unit,wherein said imaging unit includes a buffer member on a side surface facing a surface side which radiation strikes,said grid includes a grid body placed on the surface side which the radiation strikes, and a fixing unit for fixing the grid body to said imaging unit, andsides constituting the fixing unit include a side which does not protrude from an outer shape of said imaging unit when viewed from the surface side which the radiation strikes. 2. The apparatus according to claim 1, wherein said imaging unit includes a handle, anda side of said fixing unit which is perpendicular to a side located near the handle when viewed from the surface side which the radiation strikes does not protrude from the outer shape of said imaging unit. 3. The apparatus according to claim 2, wherein a side of the buffer member of said imaging unit which is parallel to the side located near the handle when viewed from the surface side which the radiation strikes includes a notched portion, andthe fixing unit is positioned by the notched portion at a side parallel to the side located near the handle, and the parallel side is a side which does not protrude from the outer shape of said imaging unit. 4. The apparatus according to claim 2, wherein the fixing unit includes bent portions, each having a substantially U-shaped cross-section, which hold said imaging unit therebetween, and is mounted on said imaging unit while holding, therebetween, the side including the handle of said imaging unit and an opposite side. 5. The apparatus according to claim 3, wherein the fixing unit includes a lock portion which locks to the handle and bent portions, each having a substantially U-shaped cross-section, which are arranged to hold said imaging unit therebetween at a position of the notched portion, and is mounted on said imaging unit while holding said imaging unit by the lock portion and the bent portions. 6. The apparatus according to claim 1, wherein the fixing unit of said grid has a shape which is bent toward said imaging unit on an incident surface side of said imaging unit so as to cover a gap corresponding to a thickness of the grid body between the grid body and the fixing unit, and so as not to protrude from a side surface.