| abstract |
An apparatus includes a pen (100, 101). The pen includes a reservoir (105, 155) configured to store a fluid. The pen also includes a tip (110, 165) configured to transfer the fluid from the reservoir onto a surface of an object (205, 210, 215, 405, 410, 415) during writing. The pen further includes a regulator (115) configured to control a flow of the fluid from the reservoir to the tip. The apparatus also includes the fluid stored within the reservoir. The fluid includes a carrier fluid and particles of an X-Ray opaque material. |