強度調控放射治療的假說(Inadequate loco-regional control of tumors is a significant barrier to cancer survival.以及Better dose distribution translate into better clinical outcomes. )由Herman Suit Credo 提出。治療計劃的宗旨是要提昇腫瘤控制機率(TCP)，與降低正常組織產生併發症機率(NTCP)，亦即將醫師所給的處方劑量(Prescription Dose)傳輸至腫瘤，同時限制周圍正常組織或危急器官(Organ at risk)的最大劑量或體積劑量。但通常要將足夠劑量給予到表淺位置的腫瘤並不容易(尤其是頭頸部腫瘤)。因此，對於這類病患在臨床上，較佳的劑量分佈與均勻性很難共存，且最佳化(Optimization)通常也費時。在此本實驗提出一種方法，藉由加上概念性的環狀似組織物來達到同時改善腫瘤的包覆性與均勻度的目標。本研究目的在於發展一套方法，藉由環狀似組織物(ring bolus)的應用，在沒有對器官造成更多傷害下，來增加腫瘤的包覆性與均勻度。

Hypothesis for Intensity Modulation Radiation Therapy : “Inadequate loco-regional control of tumors is a significant barrier to cancer survival.” and ”Better dose distribution translate into better clinical outcomes.” from Herman Suit Credo.The goal of a treatment plan is to deliver a prescribed amount of radiation to the tumor, while limiting the amount absorbed by the surrounding healthy and critical organs. But it is usually difficult or impossible to deliver a sufficient dose to a
superficial tumor , especially for tumors in head and neck. In such kinds of clinical cases, a better dose coverage and homogeneity does not coexist. The optimizations are usually time-consuming. Now, a method of simultaneously improving tumor coverage and decreasing the volume of dose above 110 % of prescription dose. This facilitates the existence of
conceptual “ring bolus”. The purpose of this study is to develop a method to improve tumor coverage and increase the tumor homogeneity without more toxicity to organs at risk by using a conceptual “ring bolus”.