The use of in vivo dosimetry within the
 combined treatment of uterine body
 cancer

Abstract

Relevance: Radiotherapy is the standard post-surgery
 treatment in patients with uterine cancer. However, radiotherapy affects 90.0–100.0% of the volume of risk organs. Information on the actual dose delivered to critical structures is needed
 to ensure the quality of radiotherapy.
 The purpose of this study was to determine the impact
 of the type of ionizing radiation on the dose load on the rectal
 mucosa using in vivo dosimetry.
 Results: At the first and tenth sessions of treatment using a
 cobalt apparatus, the in vivo dosimetry showed that the minimum value of the dose received during the tenth cycle was
 higher by 0.1 Gy. That is, the deviations from the planned dose
 were less at the same maximum values. Both the average value
 and the median during the tenth cycle were also moderately
 higher. The relative difference between the dose planned and
 received during the tenth cycle was higher than during the first
 cycle by an average of 1.12575%, with a median of 0.82214.
 When conducting radiotherapy using a linear accelerator, the
 average and median values were higher in the second measurement despite almost identical minimum and maximum
 values. The relative difference between the planned and received doses during the tenth cycle was higher than during
 the first cycle by an average of 0.55619%, with a median of
 0.42948.
 Conclusion: The conducted study showed an intro- and
 interindividual variability of in vivo dosimetry results during
 radiotherapy of genital cancer patients. In vivo dosimetric
 control showed that the relative difference between the doses
 calculated and received by the rectal mucosa upon reaching of
 20.0 Gy dose in comparison to the first irradiation cycle were
 twice higher on the ROCUS-AM cobalt apparatus vs. the Clinac
 600 C linear accelerator.
 The data obtained during the investigation indicates the
 need to develop innovative approaches to topometric preparation of genital cancer patients and to continue their dosimetric monitoring to establish the causes of discrepancies in the
 results.