Capacitive type proximity sensor

It is provided a capacitive type proximity sensor, comprising a sensing electrode, whereas the sensing electrode has a surface with electroconductive areas and not-electroconductive areas , whereas the sensor is adapted for measuring an electrical field between the sensing electrode and an object . Further it is described an apparatus for medical x-ray diagnosis and/or x-ray therapy and/or nuclear diagnosis/therapy, e.g. SPECT, a system for medical x-ray diagnosis and/or x-ray therapy and/or nuclear diagnosis/therapy, e.g. SPECT, a method for avoiding collision between an apparatus for medical x-ray diagnosis and/or x-ray therapy and/or nuclear diagnosis/therapy, e.g. SPECT, and an object, a program element and a computer readable medium. It is disclosed a capacitance type proximity sensor whose sensitivity of approaching objects has an improved independence from the special geometry of the sensor itself.