To prevent thermal stress deformation of a window of an X-ray tube by supporting dissipation of heat generated while the X-ray tube is running.

An X-ray tube cooling system includes a housing, a window frame attached to the housing, and a window attached to the window frame. The housing partitions and forms electron gaps through which electrons can pass from a cathode to an anode. The housing also partitions and forms a first inlet port and a first outlet port. The window frame partitions and forms an X-ray opening through which X-rays can pass. The window covers the X-ray opening. The housing and the window frame are configured so as a liquid can flow from the first inlet port to the first outlet port through either a first liquid path at least partially partitioned and formed by the housing or a second liquid path cooperatively partitioned and formed by the housing and the window frame. The second liquid path is disposed at least a part of a periphery of the X-ray opening.