It is provided a capacitive type proximity sensor, comprising a sensing electrode, whereas the sensing electrode has a surface with electroconductive areas 113 and not-electroconductive areas 117, whereas the sensor is adapted for measuring an electrical field 110, 112 between the sensing electrode and an object 109, 111. 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.
