Investigating the role of constrained CVT and CVT in HIPO inverse planning for HDR brachytherapy of prostate cancer

Sachpazidis, Ilias; Hense, Jürgen; Mavroidis, Panayiotis; Gainey, Mark; Baltas, Dimos

doi:10.1002/mp.13564

Cited by 4 publications

(10 citation statements)

References 48 publications

(160 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The current work has shown similar increases in coverage in the anterior sector of the prostate to the work of Sachpazidis et al 25 …”

Section: Discussionsupporting

confidence: 87%

“…In the current study, the anterior sector V100 was increased by 5.4% for freehand and 5.8% for template. In the result published by Sachpazidis et al., 25 the initial V100 of the U‐P region for CVT using 16 catheters is close to 75%, but in our case the initial V100 of the anterior sector is 89.4% ± 4.1%. Also, the anterior sector is bigger than the U‐P region by Sachpazidis et al 25 .…”

Section: Discussionsupporting

confidence: 55%

“…cancer is also found in this region. 28 In the article by Sachpazidi et al, 25 it was shown that CVT was undercovering this region. In order to evaluate the impact of our modification to CVT on the region above the urethra, the difference in dose in the anterior region is evaluated.…”

Section: Anterior Regionmentioning

confidence: 99%

“…CVT is a quick and efficient method used to optimize catheter insertion on a given geometry. 7,24,25 The CVT optimization is purely geometrical and involves a number of generators equal to the number of catheters. Each generator has a Voronoi region that corresponds to the region closest to each generator.…”

Section: Cvtmentioning

confidence: 99%

See 3 more Smart Citations

Catheters and dose optimization using a modified CVT algorithm and multi‐criteria optimization in prostate HDR brachytherapy

et al. 2022

View full text Add to dashboard Cite

Purpose: Currently, in high-dose rate (HDR) brachytherapy planning, the catheter's positions are often selected by the planner, which involves the planner's experience. The catheters are then inserted using a template that helps to guide the catheters. For certain applications, it is of interest to choose the optimal location and number of catheters needed for dose coverage and potential decrease of the treatment's toxicity. Hence, it is of great importance to develop patient-specific algorithms for catheters and dose optimization. Methods: A modified Centroidal Voronoi tessellation (CVT) algorithm is implemented and merged with a graphics processing unit (GPU)-based multi-criteria optimization algorithm (gMCO). The CVT algorithm optimizes the catheters' positions,and the gMCO algorithm optimizes the dwell times and dwell positions. The CVT algorithm can be used simultaneously for insertion with or without a template. Some improvements to the CVT algorithm are presented such as a new way of considering the area that needs to be covered. One hundred eight previously treated prostates HDR cases using real-time ultrasound are used to evaluate the different optimization procedures. The plan robustness is evaluated using two types of errors:deviations (random) in the insertion and deviation (systematic) in the reconstruction of the catheters. Results: Using gMCO on clinically inserted catheter increases the acceptance rate by 37% for Radiation Therapy Oncology Group (RTOG) criteria. Our results show that all the patients respect RTOG criteria with 11 catheters using CVT+gMCO with a template of 5 mm. The number of catheters needed for all patients to respect RTOG criteria with the freehand technique is 10 catheters using CVT+gMCO. When deviations are introduced, using a template, the acceptance rate goes to 85% with 3 mm deviations using 11 catheters. This decrease is less significant when the number of catheters is higher, decreasing by less than 5% with a 3 mm deviation using 13 catheters or more. In conclusion, it is feasible to decrease the number of catheters needed to treat most patients. Conclusions: Some cases still need a high number of catheters to reach the plan's criteria. Using gMCO allows an increase in the plan quality, while using CVT reduces the number of catheters. A higher number of catheters equates to plans that are more robust to deviations.

show abstract

“…The current work has shown similar increases in coverage in the anterior sector of the prostate to the work of Sachpazidis et al 25 …”

Section: Discussionsupporting

confidence: 87%

Section: Discussionsupporting

confidence: 55%

Section: Anterior Regionmentioning

confidence: 99%

Section: Cvtmentioning

confidence: 99%

See 2 more Smart Citations

Catheters and dose optimization using a modified CVT algorithm and multi‐criteria optimization in prostate HDR brachytherapy

et al. 2022

View full text Add to dashboard Cite

show abstract

“…P + is an overall parameter for evaluation of complex dose distributions and treatment localisations and is suggested to support decision on treatment plan selection and treatment adaptation (46,(51)(52)(53)(54)(55)(56).…”

Section: Complication Free Tumour Control Probability P+mentioning

confidence: 99%

Influence of Urethra Sparing on Tumor Control Probability and Normal Tissue Complication Probability in Focal Dose Escalated Hypofractionated Radiotherapy: A Planning Study Based on Histopathology Reference

et al. 2021

Self Cite

View full text Add to dashboard Cite

PurposeMultiparametric magnetic resonance tomography (mpMRI) and prostate specific membrane antigen positron emission tomography (PSMA-PET/CT) are used to guide focal radiotherapy (RT) dose escalation concepts. Besides improvements of treatment effectiveness, maintenance of a good quality of life is essential. Therefore, this planning study investigates whether urethral sparing in moderately hypofractionated RT with focal RT dose escalation influences tumour control probability (TCP) and normal tissue complication probability (NTCP).Patients and Methods10 patients with primary prostate cancer (PCa), who underwent 68Ga PSMA-PET/CT and mpMRI followed by radical prostatectomy were enrolled. Intraprostatic tumour volumes (gross tumor volume, GTV) based on both imaging techniques (GTV-MRI and -PET) were contoured manually using validated contouring techniques and GTV-Union was created by summing both. For each patient three IMRT plans were generated with 60 Gy to the whole prostate and a simultaneous integrated boost up to 70 Gy to GTV-Union in 20 fractions by (Plan 1) not respecting and (Plan 2) respecting dose constraints for urethra as well as (Plan 3) respecting dose constraints for planning organ at risk volume for urethra (PRV = urethra + 2mm expansion). NTCP for urethra was calculated applying a Lyman-Kutcher-Burman model. TCP-Histo was calculated based on PCa distribution in co-registered histology (GTV-Histo). Complication free tumour control probability (P+) was calculated. Furthermore, the intrafractional movement was considered.ResultsMedian overlap of GTV-Union and PRV-Urethra was 1.6% (IQR 0-7%). Median minimum distance of GTV-Histo to urethra was 3.6 mm (IQR 2 – 7 mm) and of GTV-Union to urethra was 1.8 mm (IQR 0.0 – 5.0 mm). The respective prescription doses and dose constraints were reached in all plans. Urethra-sparing in Plans 2 and 3 reached significantly lower NTCP-Urethra (p = 0.002) without significantly affecting TCP-GTV-Histo (p = p > 0.28), NTCP-Bladder (p > 0.85) or NTCP-Rectum (p = 0.85), resulting in better P+ (p = 0.006). Simulation of intrafractional movement yielded even higher P+ values for Plans 2 and 3 compared to Plan 1.ConclusionUrethral sparing may increase the therapeutic ratio and should be implemented in focal RT dose escalation concepts.

show abstract

Simultaneous catheter and multicriteria optimization for HDR cervical cancer brachytherapy with a complex intracavity/interstitial applicator

Bélanger,

Aubin,

Lavallée

et al. 2023

Medical Physics

View full text Add to dashboard Cite

BackgroundComplex intracavity and interstitial (IC/IS) applicators, such as the Venezia applicator, can improve the HR‐CTV coverage while adequately protecting organs at risk in the treatment of cervical cancer with high‐dose‐rate (HDR) brachytherapy. Although the Venezia applicator offers more choice for catheter selection, commercially available catheter and dose optimization algorithms are still missing for complex applicators. Moreover, studies on catheter and dose optimization for IC/IS implants in the treatment of cervical cancer are still limited.PurposeThis work aims to combine a GPU‐based multi‐criteria optimization (gMCO) algorithm with a sparse catheter (SC) optimization algorithm for the Venezia applicator.MethodsFifty‐eight cervical cancer patients who received 28 Gy in 4 fx of HDR brachytherapy with the Venezia applicator (combination to external beam radiation therapy) are retrospectively revisited. The modelization of the applicator is done by virtually reconstructing all the IS catheters passing through the ring. Template catheters are reconstructed using an in‐house python script. To perform simultaneous MCO and SC optimization (SC+MCO), the objective function includes aggregated dose objectives in a weighted sum and a group sparsity term that individually penalizes the contribution of IS catheters. Plans generated with the SC+MCO algorithm are compared with plans generated with MCO using clinical catheters (CC+MCO) and the clinical plans (CP). The EMBRACE II soft constraints (planning aims) and hard constraints (limits for prescribed dose) are used as plan evaluation criteria.ResultsCC+MCO gives the most important gain with an increase up to 20.7% in meeting all EMBRACE II soft constraints compared with CP. The SC+MCO algorithm (adding catheter optimization to MCO) provides a second order increase (up to 12.1% with total acceptance rate of 60.3% or 35/58) in the acceptance rate versus CC+MCO (total increase of 32.8% vs. CP). Acceptance rate in EMBRACE II hard constraints is 98.3% (57/58) for both CC+MCO and SC+MCO versus 91.4% (53/58) for CP. The median SC+MCO optimization time is 11 s to generate a total of 5000 Pareto‐optimal plans with different catheter configurations (position and number) for each fraction.ConclusionsSimultaneous catheter and MCO optimization is clinically feasible for HDR cervical cancer brachytherapy using the Venezia applicator. Clinical catheter configurations could be improved and/or the catheter number could be reduced without decreasing plan quality using SC+MCO compared with the CP.

show abstract

Investigating the role of constrained CVT and CVT in HIPO inverse planning for HDR brachytherapy of prostate cancer

Cited by 4 publications

References 48 publications

Catheters and dose optimization using a modified CVT algorithm and multi‐criteria optimization in prostate HDR brachytherapy

Catheters and dose optimization using a modified CVT algorithm and multi‐criteria optimization in prostate HDR brachytherapy

Influence of Urethra Sparing on Tumor Control Probability and Normal Tissue Complication Probability in Focal Dose Escalated Hypofractionated Radiotherapy: A Planning Study Based on Histopathology Reference

Simultaneous catheter and multicriteria optimization for HDR cervical cancer brachytherapy with a complex intracavity/interstitial applicator

Contact Info

Product

Resources

About