REFERENCE POINT DOSE VERIFICATION IN 3D AND IMRT PLAN USING INDEPENDENT SOFTWARE

Abstract

The purpose of this research is to apply the independent dose calculation for verifying the patient point dose calculated by Eclipse treatment planning system (TPS) in 3D and IMRT techniques as a process of patient specific quality assurance (QA). The MuCheck software was validated by comparing to water phantom measurement for open, wedged fields with the various field sizes as the recommendation of AAPM-TG53 and IAEA-TRS 430. The patient plans in 3D and IMRT for brain, head and neck, breast and pelvis region were randomly chosen from TPS to convert into verification plan and measured in water phantom. After the measurement and MuCheck calculation for basic field and clinical field were verified, the MuCheck software was used as an independent calculation in the real circumstance of treatment for 3D and IMRT in various regions. The point of verification was selected in the uniform dose volume. The limit of confidence of dose differences between MuCheck calculation and measurement in water phantom were within 2.1%, 2.6%, 1.3% and 4.8% for open field, wedged field, composited field in 3D and composite field in IMRT technique, respectively. Clinical application of MuCheck was performed in 301 cases of cancer in brain, head & neck, breast and pelvis regions treated with 3D and IMRT. The clinical use of MuCheck in 3D technique showed the mean difference from Eclipse of 2.57 ± 1.16%, 1.85 ± 2.87%, 1.44 ± 0.84% for brain, breast, and pelvis region, respectively, and 1.98 ± 1.87% for the mean difference of these three treatment regions. The clinical use of MuCheck in IMRT technique showed the dose discrimination from Eclipse of 0.85 ± 3.12%, 0.94 ± 3.54%, -1.12 ± 2.30%, 1.35 ± 2.74% for brain, head & neck, breast and pelvis region, and 0.52 ± 3.11% for the mean of four treatment regions. The MuCheck independent dose calculation software can be employed as a verification tool in patient specific QA for all regions of treatment in advanced treatment techniques. The point dose should be compared point to point between MuCheck calculation and Eclipse calculation in the uniform dose volume.