BACKGROUND: Brachytherapy of cervix carcinoma often results in high doses to surrounding structures, such as rectum and bladder. Therefore, these organs should be closely monitored. Purpose of this work was to evaluate rectal marker made in our institution for rectal dose measurements by comparing it with the method recommended in ICRU (International Commission on Radiation Units and Measurements) Report 38. METHODS: In this work rectal dosimetry was performed by two different methods. In one, rectal marker made in Institute of Oncology Sremska Kamenica was used, while in the other method recommended in ICRU Report 38 dose on ICRU rectal point was measured A total of 34 applications using Microselectron HDR and its standard applicator set were performed in a prospective way. The prescribed dose was 7.6 Gy to point A for each application. Rectal doses were calculated by Nucletron Plato Treatment Planning System. RESULTS: Differences found between the means of ICRU point R and rectal marker points Rref and Rmax were significant (P<0.002 and P<0.00002). The same result was obtained for Rref and Rmax pair (P<0.003). CONCLUSION: Maximal doses obtained using rectal marker were in most cases high- er than those obtained by ICRU method. It conforms well to several CT-based dosimetry studies where rectum dose was found to be higher from that obtained by ICRU method.
Rectal dosimetry in intracavitary applications of cervix carcinoma: Comparison of two methods