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Objective: This study compares standard commercial bolus material (Superflab) to custom prepared silicone dental impression material (CDIM) and play dough material (PDM) with respect to dosimetric properties and applicability by using ion chamber measurement and calculated dose values. Materials and Methods: The CDIM bolus was prepared by mixing dental impression silicone material with enough water to maintain a density of about 1.0 g/cm3. The prepared bolus material is applied on an RW3 solid phantom by covering 10x10 cm2 area with 0.5-1 cm thickness. Ion chamber measurements were performed separately with and without bolus material application. The setup was scanned in CT and the same procedure was repeated in the TPS using the scan data, in which the Pencil Beam Convolution dose calculation algorithm was used. To compare the effect of bolus material on tissue, the Superflab bolus and CDIM bolus were applied with 1 cm of thickness on postmastectomy scar and dose calculations on TPS were performed. Results: After comparison of the dosimetric values for Superflab, CDIM and PDM, we obtained statistically meaningful results between superflab and CDIM. For PDM, the results obtained with TPS and ion chamber measurements indicated that, it is not suitable to use in radiotherapy application due to its material properties. For the simulated skin dose values obtained at five random points on the scar tissue, the comparison of Superflab and CDIM TPS calculation results were not statistically significant. Conclusion: The CDIM is easy to prepare and apply on irregular mastectomy scar tissue and it prevents formation of air gaps in the application surface. Especially for curved anatomical regions such as scar tissue, inclusion of the bolus material in treatment planning protocol will reduce dose uncertainty in application. It is safe to use CDIM as an alternative to Superflab in radiotherapy application, whereas PDM is not useful in clinical practice due to its material properties. [ABSTRACT FROM AUTHOR]

Objective: To compare 3-dimensional conformal radiotherapy (3D-CRT) and intensity modulated radiotherapy (IMRT) techniques on the target tissue and critical organ doses in terms of dosimetry, during treatment planning of patient's post-mastectomy radiotherapy (PMRT) to the left chest wall. Materials and Methods: Twenty breast cancer patients with left-sided post-mastectomy have selected for PMRT both 3D-CRT and IMRT techniques. Dosimetric calculation of dose simulation in Eclipse treatment planning system have been performed. Organs at risk with the maximum dose, minimum dose, mean dose, D95, conformity and homogeneity indexes and total monitor unit for the Planning Target Volume were compared in terms of the critical organ doses. Results: There was no significant difference between the two treatment planning techniques in terms of maximum, minimum, mean dose and heterogeneity index (p>0.05). At low doses, the dose received at the heart was significantly lower with the 3D-CRT technique, but there was no statistically significant difference between the two techniques at the maximum and average doses in the high dose regions. Conclusion: For PMRT to the left chest wall, IMRT significantly improves the conformity of plan and reduce the high-dose volumes of ipsilateral lung and heart compared to 3D-CRT, but 3D-CRT is superior in terms of low-dose volume. [ABSTRACT FROM AUTHOR]