強度調控放射治療於現今之放射技術上佔有很重要的地位，因爲此治療方式不僅可提供高密集之輻射劑量於病灶區。而且可根據臨床需要在同一照野內調整某些區域輻射照射的時間以便減低對敏感器官約傷害，由於此項技術高度運用數學和物理的技巧、再搭配機械硬體的特殊設計，強度調控放射治療克服了某些複雜且傳統治療方式無法執行的困難，進而逐漸取代順形治療成爲放射治療之治療計劃中的主要治療方式，而強度調控放射治療之執行首先必須在電腦治療計劃系統內將射束的組合經田數學和物理的精密計算所得到的輻射劑量分佈之結果透過直線加速器里多葉片準直儀(Multi-Leaf Collimator)根據電腦治療計劃系統計算的機械開合及射時間的組合把輻射劑量給與到病人之病灶區，所以劑量準確度的驗證就變的很重要，此篇主要是描述以偏移法提高陣列式測量板在強度調控放射治療輻射劑量測量之精密性。

Dose verification check in intensity modulation radiation therapy (IMRT) frequently use either AgBr film or GAF Chromic film and usually film procession consume a lot of time, besides, the comparison in-between planning desired dose and film result is too complex to impliment for every patient. This study describe how to use Seven29 2D array by shifting method to increase the accuracy and resolution for dose verification check in intensity modulation radiation therapy (IMRT). In this study we adopted the commercial ion chamber array and its performance in the verification of radiotherapy plans. The device was the 2D Array Seven29(superscript TM) model (PTW Freiburg, Germany). This is a two-dimensional detector array with 729 ionization chambers uniformly arranged in a 27�27 matrix with an active area of 27�27 cm^2. The detector central ion chamber was set to be irradiated to the Linac-Accelerator cross hair isocenter for IMRT dose measurements. Shift method was done by taking the board original chamber center to the machine isocenter and then shift the 2D array board 0.5 cm rightward, 0.5 cm toward couch and obliquely toward right-couch direction. All the reading was re-arranged by creating a new matrix for these three shift results. A new result assembly shifting reading then renormalized to the isocenter to get the new dose matrix for comparing with the original without shifting reading to analysis the difference. A better resolution and more precise dose distribution had been observed when using the shifting method in Seven29 2D array in IMRT dose verification.