【摘要】 目的 分析重力因素對二維探測器陣列驗(yàn)證靜態(tài)調(diào)強(qiáng)計(jì)劃的影響，判斷機(jī)架角度歸為0°的測量方法是否安全可靠。 方法 在0°機(jī)架角和實(shí)際治療機(jī)架角分別測量靜態(tài)調(diào)強(qiáng)計(jì)劃的劑量分布，以3 mm范圍內(nèi)偏差 lt;3%(3% 3 mm)標(biāo)準(zhǔn)進(jìn)行γ分析，獲得相對于參考劑量分布的通過率，分析通過率變化規(guī)律。分析兩種方法測量的等中心點(diǎn)絕對劑量的差異。 結(jié)果 通過率的變化呈隨機(jī)分布，96.9%的照射野偏差 lt;2.5%。所有計(jì)劃的85.7%絕對劑量偏差 lt;2%，最大偏差為4.75%。 結(jié)論 使用二維探測器陣列在0°角進(jìn)行調(diào)強(qiáng)計(jì)劃的日常驗(yàn)證是安全可靠的。
【Abstract】 Objective To analyze impacts of gravity on the verification of IMRT plans with 2-Dimensional detector arrays and to evaluate the reliability of the measurements in vertical direction (gantry angle=0). Methods The dose distributions for each beam in IMRT plans were measured with 0 degree gantry angle and actual gantry angle respectively. The γ percentage pass rate (according to 3% 3 mm) for each beam under each angle condition was obtained by the comparison between the measured dose distribution and the calculated dose map from the treatment planning system which was treated as the reference distribution. Then the absolute dose at the isocenter for each plan was measured at each angle condition and was analyzed. Results The variations of γ percentage pass rates between the two types of measurements were randomly distributed, and the deviations for 96.9% beams were less than±2.5%. The differences between absolute doses for 85.7% beams were less than±2% and the biggest deviation was -4.75%. Conclusion Verification of IMRT plans for the radiotherapy quality assurance using 2-Dimensional detector arrays in 0 degree gantry angle is safe and reliable.
引用本文： 徐慶豐,周莉,李濤,彭光,傅玉川,柏森. 重力對二維探測器陣列驗(yàn)證靜態(tài)調(diào)強(qiáng)計(jì)劃的影響. 華西醫(yī)學(xué), 2010, 25(12): 2143-2146. doi: 復(fù)制
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- 2. Letourneau D, Gulam M, Yan D, et al. Evaluation of a 2D diode array for IMRT quality assurance[J]. Radiother Oncol, 2004, 70(2): 199-206.
- 3. Low DA, Harms WB, Mutic S, et al. A technique for the quantitative evaluation of dose distributions[J]. Med Phys, 1998, 25(5): 656-661.
- 4. Low DA, Dempsey JF. Evaluation of the gamma dose distribution comparison method[J]. Med Phys, 2003, 30(9): 2455-2464.
- 5. Nelms BE, Simon JA. A survey on planar IMRT QA analysis[J]. J Appl Clin Med Phys, 2007, 8(3): 2448-2463.