Hybrid pixel detectors (HPD) are nowadays well known and
widely used in fundamental research, e.g. in high energy physics
experiments. Over the last decade, segmented semiconductor detectors
have also found use in medicine. The total doses received by medical
radiation detectors often reach a significant level (up to several
hundreds of kGy per decade), especially in applications such as
transmission portal in-vivo dosimetry. Such doses might affect
detector properties. Therefore, it is necessary to evaluate their
performance after absorbing a significant radiation dose. PantherPix
is a novel 2D hybrid pixel detector which is designed specifically
for use in radiation therapy. As was concluded in earlier studies,
it is suitable for radiotherapy quality assurance (QA) and portal
dosimetry. In this paper, the PantherPix radiation hardness is
investigated using a 60Co source. The dependence on dose of the
full depletion voltage, leakage current, detector power consumption
and detector response are provided. The PantherPix radiation
tolerance has been shown to be adequate for common cumulative doses
delivered to radiation detectors in radiotherapy over several
decades and its performance has been verified for doses up to 3000
kGy.