Two-dimensional inverse planning and delivery for precision preclinical radiobiological investigations

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

Stewart, J.M.P.^1,2 ; Lindsay, P.E.^2,3 ; Jaffray, D.A.^1,2,3,4,5

Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada^1

Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada^2

Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada^3

Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada^4

Techna Institute for the Advancement of Technology for Health, Toronto, ON, Canada^5

关键词: Dose distributions;    Inverse planning;    Kernel distribution;    Optimization algorithms;    Optimization framework;    Radiochromic film;    Sequential quadratic programming;    Targeting accuracy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012061/pdf
DOI  :  10.1088/1742-6596/489/1/012061

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Advances in preclinical radiotherapy systems have provided the technical foundations for delivering highly heterogeneous dose distributions for unique radiobiological experiments, but methods to deliver arbitrary dose distributions are in their infancy. This study developed a method to optimize and automatically deliver planar dose distributions on a recently developed preclinical radiotherapy platform. The method was based on empirically determined dose kernel distributions from radiochromic film measurements. These kernels were used to determine optimal animal stage positions and beam weights to deliver a desired dose distribution at a given depth using a sequential quadratic programming optimization algorithm. The method was validated by end-to-end delivery of two dosimetric challenges designed to quantify targeting and dosimetric accuracy. The results revelead an overall targeting accuracy of 112 μm and a dosimetric delivery error, calculated along four line profiles in radiochromic film measurements, of 6.8%. Mean absolute delivery error across a linear dose gradient between 0 and 1 Gy over 7.5 mm was 0.03 Gy. These results confirm the optimization framework is an effective platform for delivery of millimetre scale heterogeneous dose distributions with sub-millimetre accuracy.