open access

Vol 19, No 6 (2014)
Original research articles
Published online: 2014-11-01
Submitted: 2013-05-28
Get Citation

Implementation of a dose gradient method into optimization of dose distribution in prostate cancer 3D-CRT plans

Marta K. Giżyńska, Paweł F. Kukołowicz, Paweł Kordowski
DOI: 10.1016/j.rpor.2014.04.007
·
Rep Pract Oncol Radiother 2014;19(6):385-391.

open access

Vol 19, No 6 (2014)
Original research articles
Published online: 2014-11-01
Submitted: 2013-05-28

Abstract

Aim

The aim of this work is to present a method of beam weight and wedge angle optimization for patients with prostate cancer.

Background

3D-CRT is usually realized with forward planning based on a trial and error method. Several authors have published a few methods of beam weight optimization applicable to the 3D-CRT. Still, none on these methods is in common use.

Materials and methods

Optimization is based on the assumption that the best plan is achieved if dose gradient at ICRU point is equal to zero. Our optimization algorithm requires beam quality index, depth of maximum dose, profiles of wedged fields and maximum dose to femoral heads. The method was tested for 10 patients with prostate cancer, treated with the 3-field technique. Optimized plans were compared with plans prepared by 12 experienced planners. Dose standard deviation in target volume, and minimum and maximum doses were analyzed.

Results

The quality of plans obtained with the proposed optimization algorithms was comparable to that prepared by experienced planners. Mean difference in target dose standard deviation was 0.1% in favor of the plans prepared by planners for optimization of beam weights and wedge angles. Introducing a correction factor for patient body outline for dose gradient at ICRU point improved dose distribution homogeneity. On average, a 0.1% lower standard deviation was achieved with the optimization algorithm. No significant difference in mean dose–volume histogram for the rectum was observed.

Conclusions

Optimization shortens very much time planning. The average planning time was 5[[ce:hsp sp="0.25"/]]min and less than a minute for forward and computer optimization, respectively.

Abstract

Aim

The aim of this work is to present a method of beam weight and wedge angle optimization for patients with prostate cancer.

Background

3D-CRT is usually realized with forward planning based on a trial and error method. Several authors have published a few methods of beam weight optimization applicable to the 3D-CRT. Still, none on these methods is in common use.

Materials and methods

Optimization is based on the assumption that the best plan is achieved if dose gradient at ICRU point is equal to zero. Our optimization algorithm requires beam quality index, depth of maximum dose, profiles of wedged fields and maximum dose to femoral heads. The method was tested for 10 patients with prostate cancer, treated with the 3-field technique. Optimized plans were compared with plans prepared by 12 experienced planners. Dose standard deviation in target volume, and minimum and maximum doses were analyzed.

Results

The quality of plans obtained with the proposed optimization algorithms was comparable to that prepared by experienced planners. Mean difference in target dose standard deviation was 0.1% in favor of the plans prepared by planners for optimization of beam weights and wedge angles. Introducing a correction factor for patient body outline for dose gradient at ICRU point improved dose distribution homogeneity. On average, a 0.1% lower standard deviation was achieved with the optimization algorithm. No significant difference in mean dose–volume histogram for the rectum was observed.

Conclusions

Optimization shortens very much time planning. The average planning time was 5[[ce:hsp sp="0.25"/]]min and less than a minute for forward and computer optimization, respectively.

Get Citation

Keywords

3D-CRT; Prostate; Beam weights; Wedges

About this article
Title

Implementation of a dose gradient method into optimization of dose distribution in prostate cancer 3D-CRT plans

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 19, No 6 (2014)

Pages

385-391

Published online

2014-11-01

DOI

10.1016/j.rpor.2014.04.007

Bibliographic record

Rep Pract Oncol Radiother 2014;19(6):385-391.

Keywords

3D-CRT
Prostate
Beam weights
Wedges

Authors

Marta K. Giżyńska
Paweł F. Kukołowicz
Paweł Kordowski

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