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Jeffrey V Siebers

Profession: Medical Physics and Engineering

Specialty: External beam radiation therapy dose evaluation

 

Robust optimization

The aim of robust optimization is to create radiation therapy treatment plans which are capable of the treatment prescription for the range of conditions which can occur during treatment delivery.  That is, the optimization is robust to uncertainties inherent to patient setup, tissue motion and deformation, target and organ delineation, and radiation dose delivery.  As such, robust optimization can also be termed “uncertainty informed” optimization. 

In addition to publications on robust optimization (also known as probabilistic treatment planning or coverage optimized planning), 3-6,10,11,19 my research group has investigated quantifying errors and uncertainties in robust-optimization sub-processes, such as deformable dose mapping13-17,20-24 and dose calculation and optimization (See CV). 

Treatment delivery quality control

My research group is advancing methods for treatment delivery quality control including use of electronic portal imaging devices (EPIDs) for pre- and during-treatment quality control and characterizing the sensitivity and specificity of both the detector system and the error detection metric for prevention of clinically significant beam delivery errors. 1,2,7-9,12,18

Radiation therapy process automation

My research often requires consistent evaluation of the processes under study for a large number of cases in order to demonstrate statistical significance.  Consistency has been achieved via creation and execution of automated processes and scripts.  We are now extending the automation to clinical treatment planning and quality assurance.

As individual patient characteristics should influence the treatment decision, our automated systems are being designed to plan several treatment options, permitting the physician and patient to individualize the treatment decision.  To ease decision making, we are studying decision support systems to assist decision space navigation.

References

1J. Gordon and J. Siebers, "Addressing a gap in current IMRT quality assurance," Int J Radiat Oncol Biol Phys 87 (1), 20-1 (2013),

2J. J. Gordon, J. K. Gardner, S. Wang, and J. V. Siebers, "Reliable detection of fluence anomalies in EPID-based IMRT pretreatment quality assurance using pixel intensity deviations," Med Phys 39 (8), 4959-75 (2012),

3J. J. Gordon, N. Sayah, E. Weiss, and J. V. Siebers, "Coverage optimized planning: probabilistic treatment planning based on dose coverage histogram criteria," Med Phys 37 (2), 550-63 (2010), 2816984.

4J. J. Gordon and J. V. Siebers, "Evaluation of dosimetric margins in prostate IMRT treatment plans," Med Phys 35 (2), 569-75 (2008), PMC2663592.

5J. J. Gordon and J. V. Siebers, "Coverage-based treatment planning: optimizing the IMRT PTV to meet a CTV coverage criterion," Med Phys 36 (3), 961-73 (2009),

6J. J. Gordon, E. Weiss, O. K. Abayomi, J. V. Siebers, and N. Dogan, "The effect of uterine motion and uterine margins on target and normal tissue doses in intensity modulated radiation therapy of cervical cancer," Physics in medicine and biology 56 (10), 2887-901 (2011), In Process.

7P. J. Keall, A. D. Todor, S. S. Vedam, C. L. Bartee, J. V. Siebers, V. R. Kini, and R. Mohan, "On the use of EPID-based implanted marker tracking for 4D radiotherapy," Medical Physics 31, 3492 (2004),

8L. Ko, J. O. Kim, and J. V. Siebers, "Investigation of the optimal backscatter for an aSi electronic portal imaging device," Phys Med Biol 49 (9), 1723-38 (2004),

9W. Li, J. V. Siebers, and J. A. Moore, "Using fluence separation to account for energy spectra dependence in computing dosimetric a-Si EPID images for IMRT fields," Medical Physics 33 (12), 4468-4480 (2006),

10J. A. Moore, J. J. Gordon, M. Anscher, J. Silva, and J. V. Siebers, "Comparisons of treatment optimization directly incorporating systematic patient setup uncertainty with a margin-based approach," Med Phys 39 (2), 1102-11 (2012), 3293365.

11J. A. Moore, J. J. Gordon, M. S. Anscher, and J. V. Siebers, "Comparisons of treatment optimization directly incorporating random patient setup uncertainty with a margin-based approach," Med Phys 36 (9), 3880-90 (2009), PMC2738738.

12J. A. Moore and J. V. Siebers, "Verification of the optimal backscatter for an aSi electronic portal imaging device," Phys Med Biol 50 (10), 2341-50 (2005),

13M. J. Murphy, F. J. Salguero, J. V. Siebers, D. Staub, and C. Vaman, "A method to estimate the effect of deformable image registration uncertainties on daily dose mapping," Med Phys 39 (2), 573-80 (2012), 3267790.

14N. K. Saleh-Sayah, E. Weiss, F. J. Salguero, and J. V. Siebers, "A distance to dose difference tool for estimating the required spatial accuracy of a displacement vector field," Medical Physics 38 (5), 2318-23 (2011), 3098891.

15F. J. Salguero, N. K. Saleh-Sayah, C. Yan, and J. V. Siebers, "Estimation of three-dimensional intrinsic dosimetric uncertainties resulting from using deformable image registration for dose mapping," Medical Physics 38 (1), 343-53 (2011), 3021560.

16M. Sharma, E. Weiss, and J. V. Siebers, "Dose deformation-invariance in adaptive prostate radiation therapy: Implication for treatment simulations," Radiother Oncol 105 (2), 207-13 (2012),

17J. V. Siebers and H. Zhong, "An energy transfer method for 4D Monte Carlo dose calculation," Med Phys 35 (9), 4096-105 (2008), PMC2663593.

18S. Wang, J. K. Gardner, J. J. Gordon, W. Li, L. Clews, P. B. Greer, and J. V. Siebers, "Monte Carlo-based adaptive EPID dose kernel accounting for different field size responses of imagers," Med Phys 36 (8), 3582-95 (2009), PMC2724176.

19H. Xu, J. J. Gordon, and J. V. Siebers, "Sensitivity of postplanning target and OAR coverage estimates to dosimetric margin distribution sampling parameters," Medical Physics 38 (2), 1018-27 (2011), PMC3045415.

20C. Yan, G. Hugo, F. J. Salguero, N. Saleh-Sayah, E. Weiss, W. C. Sleeman, and J. V. Siebers, "A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations," Med Phys 39 (4), 2119-28 (2012), 3326071.

21C. Yan, H. Zhong, M. Murphy, E. Weiss, and J. V. Siebers, "A pseudoinverse deformation vector field generator and its applications," Med Phys 37 (3), 1117-28 (2010), 2837727.

22H. Zhong, T. Peters, and J. V. Siebers, "FEM-based evaluation of deformable image registration for radiation therapy," Phys Med Biol 52 (16), 4721-38 (2007),

23H. Zhong and J. V. Siebers, "Monte Carlo dose mapping on deforming anatomy," Phys Med Biol 54 (19), 5815-5830 (2009), PMC2849146.

24H. Zhong, E. Weiss, and J. V. Siebers, "Assessment of dose reconstruction errors in image-guided radiation therapy," Phys Med Biol 53 (3), 719-36 (2008), PMC2819061.