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