HDR Prostate Brachytherapy Research Articles

Individualized Dose-Escalation of HDR Prostate Brachytherapy Implant to Decrease Required External Beam Radiation Dose: A Retrospective Feasibility Study

PurposeHigh-dose-rate brachytherapy (HDR-BT) is commonly combined with external beam radiation therapy (EBRT) for the treatment of localized prostate cancer. Escalating the HDR-BT dose as far as organ-at-risk (OAR) constraints allow, on a personalized basis, would allow for a reduction in EBRT dose while achieving similar total biologic equivalence. The primary objective of this study was to determine the dosimetric feasibility of escalating the HDR-BT dose from 15 Gy to 16 or 17 Gy while continuing to meet OAR constraints from the original 15 Gy plan on an individualized basis. Methods and materialsA total of 53 consecutive HDR-BT plans were retrospectively assessed to determine what percentage of plans could be reoptimized to deliver a dose of 16 Gy or 17 Gy, while meeting defined 15-Gy OAR constraints. Factors independently associated with dose escalation were examined. ResultsThirty-nine plans (74%) and 2 plans (4%) were successfully escalated to a dose of 16 Gy and 17 Gy, respectively. Rectum V80 and urethra Dmax were independently predictive of the ability to dose escalate to 16 Gy. ConclusionsIndividualized HDR-BT dose escalation beyond 15 Gy without compromising OAR constraints is dosimetrically feasible. This approach could allow for a corresponding reduction of EBRT fractions (ie, from 15 to 12 fractions) and would be beneficial in terms of resource savings for departments, convenience for patients, and potentially better tolerance of treatment with the expected reduction in biologically equivalent doses to OARs. A clinical trial is being developed to investigate the efficacy and tolerance of personalized HDR-BT/EBRT dose fractionation for localized intracapsular prostate cancer.

Individualized Dose-Escalation of HDR Prostate Brachytherapy Implant to Decrease Required External Beam Radiation Dose: A Retrospective Feasibility Study

Abstract Purpose High-dose-rate brachytherapy (HDR-BT) is commonly combined with external beam radiation therapy (EBRT) for the treatment of localized prostate cancer. Escalating the HDR-BT dose as far as organ-at-risk (OAR) constraints allow, on a personalized basis, would allow for a reduction in EBRT dose while achieving similar total biologic equivalence. The primary objective of this study was to determine the dosimetric feasibility of escalating the HDR-BT dose from 15 Gy to 16 or 17 Gy while continuing to meet OAR constraints from the original 15 Gy plan on an individualized basis. Methods and materials A total of 53 consecutive HDR-BT plans were retrospectively assessed to determine what percentage of plans could be reoptimized to deliver a dose of 16 Gy or 17 Gy, while meeting defined 15-Gy OAR constraints. Factors independently associated with dose escalation were examined. Results Thirty-nine plans (74%) and 2 plans (4%) were successfully escalated to a dose of 16 Gy and 17 Gy, respectively. Rectum V80 and urethra Dmax were independently predictive of the ability to dose escalate to 16 Gy. Conclusions Individualized HDR-BT dose escalation beyond 15 Gy without compromising OAR constraints is dosimetrically feasible. This approach could allow for a corresponding reduction of EBRT fractions (ie, from 15 to 12 fractions) and would be beneficial in terms of resource savings for departments, convenience for patients, and potentially better tolerance of treatment with the expected reduction in biologically equivalent doses to OARs. A clinical trial is being developed to investigate the efficacy and tolerance of personalized HDR-BT/EBRT dose fractionation for localized intracapsular prostate cancer.

A GPU-based multi-criteria optimization algorithm for HDR brachytherapy

Currently in HDR brachytherapy planning, a manual fine-tuning of an objective function is necessary to obtain case-specific valid plans. This study intends to facilitate this process by proposing a patient-specific inverse planning algorithm for HDR prostate brachytherapy: GPU-based multi-criteria optimization (gMCO).Two GPU-based optimization engines including simulated annealing (gSA) and a quasi-Newton optimizer (gL-BFGS) were implemented to compute multiple plans in parallel. After evaluating the equivalence and the computation performance of these two optimization engines, one preferred optimization engine was selected for the gMCO algorithm. Five hundred sixty-two previously treated prostate HDR cases were divided into validation set (100) and test set (462). In the validation set, the number of Pareto optimal plans to achieve the best plan quality was determined for the gMCO algorithm. In the test set, gMCO plans were compared with the physician-approved clinical plans.Our results indicated that the optimization process is equivalent between gL-BFGS and gSA, and that the computational performance of gL-BFGS is up to 67 times faster than gSA. Over 462 cases, the number of clinically valid plans was 428 (92.6%) for clinical plans and 461 (99.8%) for gMCO plans. The number of valid plans with target coverage greater than 95% was 288 (62.3%) for clinical plans and 414 (89.6%) for gMCO plans. The mean planning time was 9.4 s for the gMCO algorithm to generate 1000 Pareto optimal plans.In conclusion, gL-BFGS is able to compute thousands of SA equivalent treatment plans within a short time frame. Powered by gL-BFGS, an ultra-fast and robust multi-criteria optimization algorithm was implemented for HDR prostate brachytherapy. Plan pools with various trade-offs can be created with this algorithm. A large-scale comparison against physician approved clinical plans showed that treatment plan quality could be improved and planning time could be significantly reduced with the proposed gMCO algorithm.

Commissioning and Clinical Use of the Uronav Therapy System with the Electromagnetic Tracking Technology for Intra-Op US Guided Prostate HDR

To commission, evaluate and test clinical workflows for the new real-time prostate HDR brachytherapy treatment system Uronav Therapy from InVivo (Philips).

PO-1052 Is there a clinically meaningful change in anatomy during planning of US HDR prostate brachytherapy?

PO-1052 Is there a clinically meaningful change in anatomy during planning of US HDR prostate brachytherapy?

EP-2152 Pre-rectal spacing w/. Blood Patch in HDR Prostate Brachytherapy, Feasibility and Dosimetric Analysis

EP-2152 Pre-rectal spacing w/. Blood Patch in HDR Prostate Brachytherapy, Feasibility and Dosimetric Analysis

OC-0400 Are prostate contours affected by the RO's clinical experience in prostate HDR brachytherapy?

OC-0400 Are prostate contours affected by the RO's clinical experience in prostate HDR brachytherapy?

EP-1571 Pelvis Hypofractionarion in IMRT + IGRT:15 fractions and prostate HDR Brachytherapy. Toxicity analysis

EP-1571 Pelvis Hypofractionarion in IMRT + IGRT:15 fractions and prostate HDR Brachytherapy. Toxicity analysis

PO-1059 Separation and rectal dosimetry with a hydrogel spacer inserted during prostate HDR brachytherapy

PO-1059 Separation and rectal dosimetry with a hydrogel spacer inserted during prostate HDR brachytherapy

OC-0395 Bi-objective optimization of dosimetric indices for HDR prostate brachytherapy within 30 seconds

OC-0395 Bi-objective optimization of dosimetric indices for HDR prostate brachytherapy within 30 seconds

OC-0396 Robust HDR prostate brachytherapy planning accounting for organ reconstruction settings

OC-0396 Robust HDR prostate brachytherapy planning accounting for organ reconstruction settings

Robust Optimization of Dose-Volume Metrics for Prostate HDR-Brachytherapy Incorporating Target and OAR Volume Delineation Uncertainties

In radiation therapy planning, uncertainties in the definition of the target volume yield a risk of underdosing the tumor. The traditional corrective action in the context of external beam radiotherapy (EBRT) expands the clinical target volume (CTV) with an isotropic margin to obtain the planning target volume (PTV). However, the EBRT-based PTV concept is not directly applicable to brachytherapy (BT) since it can lead to undesirable dose escalation. Here, we present a treatment plan optimization model that uses worst-case robust optimization to account for delineation uncertainties in interstitial high-dose-rate BT of the prostate. A scenario-based method was developed that handles uncertainties in index sets. Heuristics were included to reduce the calculation times to acceptable proportions. The approach was extended to account for delineation uncertainties of an organ at risk (OAR) as well. The method was applied on data from prostate cancer patients and evaluated in terms of commonly used dosimetric performance criteria for the CTV and relevant OARs. The robust optimization approach was compared against the classical PTV margin concept and against a scenario-based CTV margin approach. The results show that the scenario-based margin and the robust optimization method are capable of reducing the risk of underdosage to the tumor. As expected, the scenario-based CTV margin approach leads to dose escalation within the target, whereas this can be prevented with the robust model. For cases where rectum sparing was a binding restriction, including uncertainties in rectum delineation in the planning model led to a reduced risk of a rectum overdose, and in some cases, to reduced targetcoverage. The online supplement is available at https://doi.org/10.1287/ijoc.2018.0815 .

On-line image-guided HDR brachytherapy (IGBT) for prostate cancer using ultrasound based real-time solution

A new solution exists for prostate HDR brachytherapy, allowing seamless real-time procedure based on ultrasound imaging, compared a conventional approach with separate sessions for catheter insertion, CT imaging, planning and verification before treatment. This introduces a new paradigm into HDR brachytherapy procedure – no requirement for patient transfer while enabling real-time image guidance throughout the procedure including ‘beam-on’ time. In this work a seamless integration of real-time workflow has been designed, which demonstrates the efficacy of ‘plan and treat’ solution, in particular, with minimising geometric miss via a new on-line image guidance protocol.

A simulation study of BrachyShade, a shadow-based internal source tracking system for HDR prostate brachytherapy

This paper presents a simulation study of BrachyShade, a proposed internal source-tracking system for real time quality assurance in high dose rate prostate brachytherapy. BrachyShade consists of a set of spherical tungsten occluders located above a pixellated silicon photodetector. The source location is estimated by minimising the mean squared error between a parametric model of the shadow image and acquired images of the shadows projected on the detector plane. A novel algorithm is finally employed to correct the systemic error resulting from Compton scattering in the medium. The worst-case error obtained with BrachyShade for a 13.5 ms image acquisition is less than 1.3 mm in the most distant part of the treatment volume, while for 75% of source locations an error of less than 0.42 mm was achieved.

A multi-criteria optimization approach for HDR prostate brachytherapy: II. Benchmark against clinical plans

The current iterative approach to inverse planning of high dose rate treatment planning can be time consuming. The purpose of this two-part study is to streamline the planning process while maintaining plan quality. In this second part, a multi-criteria optimization (MCO) planning algorithm is proposed and benchmarked against a standard planning algorithm.With a set of previously established regression models, a patient-specific valid solution space on the Pareto surface was predicted based on the anchor plans results. Alternative plans generated alongside the partial Pareto front were presented to the planner, and one plan was selected as the MCO plan. The dosimetric parameters results as well as the planning time were compared between the MCO plans and the physician-approved standard plans for 236 prostate cases.Results show that the urethra is better spared with MCO planning than with standard planning (a lower mean urethral D10 value of 2.25%). The overall MCO plan quality also outperforms the standard plan quality, since MCO planning is able to increase the frequency of clinically acceptable plans meeting all of RTOG criteria simultaneously without any human intervention (from 83.05% to 97.46%). Finally, the average MCO planning time is without any interventions of treatment planners.The presented MCO planning algorithm constitutes a robust and automated way to improve treatment quality in brachytherapy.

OA088] Prostate HDR brachytherapy: the experience of the team matters

Purpose To evaluate the learning curve of the BT-team performing prostate HDR brachytherapy (BT) at our Institution. Methods Since 2010, 108 prostate BT treatments were performed at our Institution by the same BT-team (2 Radiation Oncologists, 2 Medical Physicists), using transrectal ultrasound-guided real time treatment planning. To evaluate the learning curve of the BT-team, Dose Homogeneity Index (DHI) and Conformity Index (COIN) were evaluated. According to the experienced treatment planning difficulties, a new index called Optimal Plan Index (OPI) was also established and evaluated. OPI was defined as the dose to 95% of the prostate (D95%) divided by the dose to 0.1 cc of the urethra (D0.1 cc). The prescribed dose ( D prescr ) was 14 Gy to the prostate surface and the most difficult planning goals were: D95% > 95% D prescr and D0.1 cc 115% D prescr . The number of needles used for the procedure was also investigated. Results DHI and COIN didn’t show any correlation with the increasing experience of the BT team, whereas OPI resulted to be a good indicator of the learning curve. Average OPI values and number of needles used for the procedure, calculated for every group of 27 patients taken in chronological order, were 0.80 ± 0.05, 0.85 ± 0.06, 0.89 ± 0.03, 0.89 ± 0.02, and 17.6 ± 3.2, 19.4 ± 3.3, 17.2 ± 1.2, 16.8 ± 1.5, for group 1 (G1), 2 (G2), 3 (G3) and 4 (G4), respectively. OPI significantly increased with time (i.e., G1vsG2 p Conclusions The quality of HDR prostate BT is operator dependent and the proposed optimal plan index OPI is a good indicator of the learning curve of a BT-team. OPI and needle analysis, combined with a specific education of the involved clinical personnel, was useful to improve some treatment planning strategies at our Institution.

Development of a Surrogate Urethra for Real-Time Planning of High-Dose-Rate Prostate Brachytherapy

To develop a simple but realistic surrogate urethra that can be utilized for improved prediction of urethral dose during real-time HDR prostate brachytherapy (HDR-PB). The cross-sectional shape of the prostatic urethra was mapped in detail throughout the length of the prostate and used to create a clinically useful surrogate urethra cross-section that can be positioned using the visualized Foley catheter in real-time planning.

The Clinical Efficiency and Learning Curve of Ultrasound (us)-Based Planning in High Dose Rate (hdr) Prostate Brachytherapy

The Clinical Efficiency and Learning Curve of Ultrasound (us)-Based Planning in High Dose Rate (hdr) Prostate Brachytherapy

Late Toxicity after Single Dose HDR Prostate Brachytherapy and EBRT for Localized Prostate Cancer: Clinical and Dosimetric Predictors in a Prospective Cohort Study

Late Toxicity after Single Dose HDR Prostate Brachytherapy and EBRT for Localized Prostate Cancer: Clinical and Dosimetric Predictors in a Prospective Cohort Study

Changes In T2-Weighted Mri-Derived Radiomic Features in Patients Treated with Focal Salvage Hdr Prostate Brachytherapy for Local Recurrence after Previous External-Beam Radiotherapy

Changes In T2-Weighted Mri-Derived Radiomic Features in Patients Treated with Focal Salvage Hdr Prostate Brachytherapy for Local Recurrence after Previous External-Beam Radiotherapy