Objective.调强放射治疗(IMRT)广泛应用于临床放射治疗,用适形剂量治疗不同的恶性肿瘤。作为临床翻译的测试领域,临床前小动物实验需要模拟人体放射治疗条件,包括IMRT。然而,小动物IMRT是一个系统的挑战,由于缺乏相应的硬件和软件的小型化目标。方法。基于直接矩形孔径优化(RAO)的稀疏正交准直器(SOC)实质上简化了用于小型化的硬件。本研究调查并评估了使用SOC进行复杂小鼠辐照的显着改进的RAO算法。由于矩形孔径的Kronecker乘积表示是计算性能的主要限制,我们使用与小矩阵相乘而不是剂量负荷矩阵的Kronecker乘积来重新表述数据保真度项中的矩阵乘法。使用快速迭代收缩阈值算法(FISTA)进一步加速了对优化问题的求解。主要结果。四只老鼠的情况下,包括肝脏,脑瘤,一个凹的U型靶,和一个复杂的全骨髓照射(TMI)病例,在这项研究中包括手动描绘的目标和OAR。将七个共面场SOCIMRT(sIMRT)计划与基于理想注量图的IMRT(iIMRT)计划进行了比较。对于目标更简单和更小的前三种情况,sIMRT计划和iIMRT计划在计划目标卷(PTV)统计中的差异在1%以内。对于TMI案例,sIMRT计划在减少PTV的热点(也称为Dmax)方面更优越,肾脏,肺,心,和肠道减少20.5%,31.5%,24.67%,20.13%,和17.78%,分别。平均而言,在这项研究的四个案例中,sIMRT计划符合性与iIMRT计划相当,R50和积分剂量略有增加2.23%和2.78%。意义。显着改进的sIMRT优化方法允许在1分钟内针对较小的目标快速创建计划,并使复杂的TMI计划可行,同时通过注量图优化实现了与理想IMRT可比的剂量测定。
Objective.Intensity-modulated radiotherapy (IMRT) is widely used in clinical radiotherapy, treating varying malignancies with conformal doses. As the test field for clinical translation, preclinical small animal experiments need to mimic the human radiotherapy condition, including IMRT. However, small animal IMRT is a systematic challenge due to the lack of corresponding hardware and software for miniaturized targets.Approach.The sparse orthogonal collimators (SOC) based on the direct rectangular aperture optimization (RAO) substantially simplified the hardware for miniaturization. This study investigates and evaluates a significantly improved RAO algorithm for complex mouse irradiation using SOC. Because the Kronecker product representation of the rectangular aperture is the main limitation of the computational performance, we reformulated matrix multiplication in the data fidelity term using multiplication with small matrices instead of the Kronecker product of the dose loading matrices. Solving the optimization problem was further accelerated using the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA).Main results.Four mouse cases, including a liver, a brain tumor, a concave U-target, and a complex total marrow irradiation (TMI) case, were included in this study with manually delineated targets and OARs. Seven coplanar-field SOC IMRT (sIMRT) plans were compared with idealistic fluence map based IMRT (iIMRT) plans. For the first three cases with simpler and smaller targets, the differences between sIMRT plans and iIMRT plans in the planning target volumes (PTV) statistics are within 1%. For the TMI case, the sIMRT plans are superior in reducing hot spots (also termedDmax) of PTV, kidneys, lungs, heart, and bowel by 20.5%, 31.5%, 24.67%, 20.13%, and 17.78%, respectively. On average, in four cases in this study, the sIMRT plan conformity is comparable to that of the iIMRT\'s with lightly increased R50 and Integral Dose by 2.23% and 2.78%.Significance.The significantly improved sIMRT optimization method allows fast plan creation in under 1 min for smaller targets and makes complex TMI planning feasible while achieving comparable dosimetry to idealistic IMRT with fluence map optimization.