LAUSR

Purpose In this study, the availability of in vivo dosimetry was investigated for high accuracy applicability of the deep inspiration breathhold (DIBH) RT technique. Methods Early stage 10 left breast cancer patients underwent CT scans with breath control system and RT plans were created by using FinF technique.It was aimed to investigate the compliance of the doses received during the treatment with the intended doses of the patients by IVD. The skin depth was assumed to be 0.07 mm, the depth recommended in the ICRU 39 report. Doses calculated in TPS were compared by measured doses which were obtained by placing the TLDs and OSLs at 3, 5.5, 8 and 15 cm (contralateral breast) distances from the center of the beam on the patient’s skin and around the thyroid organ in every single fraction. Results In the study, the skin dose measurements were taken with TLD and OSL at all points. The average differences between the measured and calculated doses were found to be −15.88% and −15.65% for TLD and OSL, respectively. The average median dose differences were obtained for TLD and OSL, respectively; 2.99% (min: −83.59; max: 46.87) and −9.65% (min: −90.25; max: 57.56) for contralateral breast, 16.75% (min: −26.12; max: 91.35); −17.63% (min: −43.73; max: 84.79) for thyroid. Conclusions Measured and calculated contralateral breast dose differences change from patient to patient.Although the dose differences found for the thyroid are more or less different from each other, the values obtained by TLD were lower than the values calculated by TPS, whereas the values measured by OSL were found higher than the values calculated by TPS. Surface dose measurements by using OSL and TLD have been found to be approximately 15% greater than TPS and no superiority has been seen in the systems used in skin dosimetry. Besides, out of field doses found by OSL were higher than TPS.