Comparison of Dose-Volume Histograms in Intracavitary Brachytherapy of Cervical Cancer using Manual Plan and Inverse Optimization Technique
Jory Alanazi*, Anysja Zuchora and Leanne Berriga
Department of Radiation Therapy, King Fahad Medical City, Saudi Arabia
*Corresponding Author: Jory Alanazi, Department of Radiation Therapy, King Fahad Medical City, Saudi Arabia.
February 15, 2023; Published: March 30, 2023
Introduction: Brachytherapy treatment planning with manual technique is a common method for high-dose-rate (HDR) cervical cancer. New methods performing inverse optimization technique of the dose distribution have been developed over the recent years. The purpose of this study is to test the feasibility of an inverse optimization technique and compare it to the manual technique in terms of speed and dose-volume histogram (DVH) parameters. The aim is to finding an optimum set of constraints that will produce an inverse optimization result. This will be comparable to a manual plan in terms of coverage for high-risk clinical target volume (HR-CTV) with a prescribed dose; simultaneously decreasing the dose to organs at risk (OARs) and planning process duration.
Materials and Methods: Thirty cervical cancer patients treated with an HDR brachytherapy were included in this study. Each patient had three treatment plans with manual technique, of which each was developed using an inverse optimization technique by an expert treatment planner. The plans were created using the inverse technique, that has constant constraints on the maximum doses of the target volume and different constraints on OARs.
Results: The resulting dose-volume histogram (DVH) were compared for the manual and inverse technique. Following parameters were used: dose covering 90% (D90) of high-risk clinical target volume (HR CTV), HR CTV V100%, dose to point A, and doses to 2cm3 (D2cc) were recorded for rectum, bladder, sigmoid, and bowel. In addition, the total treatment time, and the sum of the total reference air kerma (TRAK) was recorded for each patient. The result shows that the mean of the D90 and V100% of the HR CTV for the inverse plan was similar to the manual plan. This wasn’t statistically significant. However, the mean dose of point A in the inverse plan was greater than the mean dose in the manual plan and this difference was statistically significant. Furthermore, inverse plan has a statistically significant reduction of the dose in the all OARs. The TRAK and the total treatment time resulting statistically significant reduction in inverse planning.
Conclusion: Inverse optimization is not inferior to manual treatment planning in terms of high-risk clinical target volume (HR CTV) dose coverage, and offers excellent sparing of organs at risk structures (OARs). The planning time for Inverse optimization is faster than manual plan.
Keywords: Brachytherapy; Cervical Cancer; Inverse Optimization; Treatment Planning
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