Basic Characteristic Comparison of the the SIEMENS 160MLC and the VARIAN HD120MLC
M Toyota*, M Takeshita ,Y Oku, Y Saigo , M Ikeda Kagoshima University Medical and Dental Hospital, Kagoshima, Japan, Kagoshima, KagoshimaSU-E-P-11 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: The objective of this work was to compare the basic physical characteristics of transmission, penumbra and Tongue & Groove of the Special Multi-leaf Collimator (MLC) 160 MLC, SIMENS Manufactured and HighDefinition120 (HD120), VARIAN Manufactured.
Methods:Under the conditions of 6 MV, SCD 100 cm, D-Max (1.5 cm), transmission and penumbra were measured with 3D water phantom, RFA 300, dosimeter of ionization, CC13-S and Silicon photodiode detector, Type SFD.
Leaf transmission was measured in the direction of the in-line and all leaves closed. End leaf transmission was measured in the direction of the cross-line and the part of all leaves closed was moved every 5cm in right and left. Penumbra was measured in the direction of the cross-line, and 10cm*10cm field was moved every 5cm in right and left. Tongue & Groove was measured with film, EDR2.
Results:The average of Transmission of 160 MLC, SIEMENS was 0.42%, HD120, VARIAN was 1.6%. The average of End Leaf Transmission of 160 MLC, SIEMENS was 12.2%, HD 120, VARIAN was 26.0%. Penumbra at center of 160MLC, SIEMENS was 5.7mm, HD 120, SIEMENS was 5.5mm. Maximum of Penumbra of 160MLC, SIEMENS was 6.8mm, HD 120, VARIAN was 6.2mm. The effect of Tongue & Groove of 160 MLC, SIEMENS was about 18.0%, HD 120, VARIAN was about 20.0%.
Conclusion:The difference was not found in Penumbra between 160MLC, SIEMENS and HD120, VARIAN. However, in Transmission and the effect of Tongue & Groove, 160MLC, SIEMENS was lower than HD120, VARIAN. These are depend on the effect of multiple-curved tip shape, high leaf and slant placement of leaves.