(Wednesday, 8/1/2018) 10:30 AM - 11:00 AM
Room: Exhibit Hall | Forum 9
Purpose: Dosimetric comparison of manual beam angle selection (MBS) and beam angle optimization hybriding multicriteria optimization (BAMCO) on liver cancer
Methods: In MBS, 10 liver cancer patients previously treated with standard manual coplanar 4-7 fields IMRT technique were retrospectively reviewed and enrolled in this study. In BAMCO, the selection of gantry angle was optimized by the algorithm for the same number of beams and the plan was optimized by multicriteria optimization using an MCO planning system. All ten plans were normalized to 50.4Gy to 95% of the PTV. The dose volume histogram, conformity index, homogeneity index, total segments and total monitor units (MU) were compared.
Results: Both therapeutical plans can fullfill the clinic dosimetric requirements. Our results showed that the dose-volume histograms for PTV are similar in both techniques but BAMCO provided better PTV conformity than MBS. The mean dose to the normal liver was (11.5±2.4) Gy for MBS and (10.7±2.5) Gy for BAMCO (p=0.009) , The mean dose to the right kidney was (8.1±3.9) Gy for MBS and (7.1±3.9) Gy for BAMCO (p=0.001) . Comparable sparing of normal tissues including V30 to normal liver, V20 and the mean dose to left kidney, V20 to right kidney, maximum dose to the small intestine, maximum dose to the stomach and maximum dose to the spinal cord were achieved with both plans. BAMCO produced statistically lower total MU and total segments than the MBS, the total MU in BAMCO and MBS were 322±36 and 405±64 (p=0.001), the total segments in BAMCO and MBS were 14±2 and 25±4 (p=0.000).
Conclusion: The BAMCO technique can provide a better conformity for PTV and better sparing to OARs compared with MBS. The MU and number of segments are significantly lower in BAMCO than the MBS in liver cancer.
Keywords
Not Applicable / None Entered.
Taxonomy
TH- External beam- photons: treatment planning/virtual clinical studies
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