Evaluation of deformable image registration algorithm for determination of accumulated dose for brachytherapy of cervical cancer patients

Reza Mohammadi; Seied Rabi Mahdavi; Ramin Jaberi; Zahra Siavashpour; Leila Janani; Ali Soleimani Meigooni; Reza Reiazi

doi:10.5114/jcb.2019.88762

Evaluation of deformable image registration algorithm for determination of accumulated dose for brachytherapy of cervical cancer patients

J Contemp Brachytherapy. 2019 Oct;11(5):469-478. doi: 10.5114/jcb.2019.88762. Epub 2019 Oct 30.

Authors

Reza Mohammadi^{1

2}, Seied Rabi Mahdavi¹, Ramin Jaberi³, Zahra Siavashpour⁴, Leila Janani⁵, Ali Soleimani Meigooni⁶, Reza Reiazi^{1

2}

Affiliations

¹ Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran.
² Medical Image and Signal Processing Research Core, Iran University of Medical Sciences, Tehran, Iran.
³ Radiation Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
⁴ Department of Medical Radiation Engineering, Shahid Beheshti University, Tehran, Iran.
⁵ Department of Biostatistics, Iran University of Medical Sciences, Tehran, Iran.
⁶ Comprehensive Cancer Centers of Nevada, Las Vegas, NV, United States.

Abstract

Purpose: This study was designed to assess the dose accumulation (DA) of bladder and rectum between brachytherapy fractions using hybrid-based deformable image registration (DIR) and compare it with the simple summation (SS) approach of GEC-ESTRO in cervical cancer patients.

Material and methods: Patients (n = 137) with cervical cancer treated with 3D conformal radiotherapy and three fractions of high-dose-rate brachytherapy were selected. CT images were acquired to delineate organs at risk and targets according to GEC-ESTRO recommendations. In order to determine the DA for the bladder and rectum, hybrid-based DIR was done for three different fractions of brachytherapy and the results were compared with the standard GEC-ESTRO method. Also, we performed a phantom study to calculate the uncertainty of the hybrid-based DIR algorithm for contour matching and dose mapping.

Results: The mean ± standard deviation (SD) of the Dice similarity coefficient (DICE), Jaccard, Hausdorff distance (HD) and mean distance to agreement (MDA) in the DIR process were 0.94 ±0.02, 0.89 ±0.03, 8.44 ±3.56 and 0.72 ±0.22 for bladder and 0.89 ±0.05, 0.80 ±0.07, 15.46 ±10.14 and 1.19 ±0.59 for rectum, respectively. The median (Q1, Q3; maximum) Gy_EQD2 differences of total D_2cc between DIR-based and SS methods for the bladder and rectum were reduced by -1.53 (-0.86, -2.98; -9.17) and -1.38 (-0.80, -2.14; -7.11), respectively. The mean ± SD of DICE, Jaccard, HD, and MDA for contour matching were 0.98 ±0.008, 0.97 ±0.01, 2.00 ±0.70 and 0.20 ±0.04, respectively for large deformation. Maximum uncertainty of dose mapping was about 3.58%.

Conclusions: The hybrid-based DIR algorithm demonstrated low registration uncertainty for both contour matching and dose mapping. The DA difference between DIR-based and SS approaches was statistically significant for both bladder and rectum and hybrid-based DIR showed potential to assess DA between brachytherapy fractions.

Keywords: HDR; brachytherapy; cervix; deformable image registration.