The purpose of this study was to compare two inverse planning algorithms for cervical cancer brachytherapy and a conventional manual treatment planning according to the MUW (Medical University of ...Vienna) protocol.
For 20 patients, manually optimized, and, inversely optimized treatment plans with Hybrid Inverse treatment Planning and Optimization (HIPO) and with Inverse Planning Simulated Annealing (IPSA) were created. Dosimetric parameters, absolute volumes of normal tissue receiving reference doses, absolute loading times of tandem, ring and interstitial needles, Paddick and COIN conformity indices were evaluated.
HIPO was able to achieve a similar dose distribution to manual planning with the restriction of high dose regions. It reduced the loading time of needles and the overall treatment time. The values of both conformity indices were the lowest. IPSA was able to achieve acceptable dosimetric results. However, it overloaded the needles. This resulted in high dose regions located in the normal tissue. The Paddick index for the volume of two times prescribed dose was outstandingly low.
HIPO can produce clinically acceptable treatment plans with the elimination of high dose regions in normal tissue. Compared to IPSA, it is an inverse optimization method which takes into account current clinical experience gained from manual treatment planning.
Conducting life cycle assessments (LCA) of complex multi-line, multi-product manufacturing facilities can be challenging. There is no standard method to assign or allocate resource use and ...environmental impacts to the individual products. The Industrial Process System Assessment method is presented to address this gap in current approaches for LCA allocation by making use of a multiscale model of process systems. Algorithms for the allocation procedure rectify process, ancillary, and non-process data from a facility such that inputs (e.g., raw materials) and outputs (e.g., emissions) can be assigned to a particular product from a particular line. The allocation approach demonstrates systematic multiscale process model development to avoid arbitrary allocation assumptions. This standardized method will enable LCA practitioners and process engineers to more clearly differentiate resource use and environmental impacts of co-products from complex facilities. The model could be further extended to provide product allocation based on individual unit operations when data are available.
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•The Industrial Process System Assessment (IPSA) is introduced.•IPSA bridges multiple process system scales (production line to facility).•IPSA provides more accurate allocation of inputs and outputs for LCA.•IPSA is applicable to a particular product in multi-product systems.•IPSA is extendable to other scales of a manufacturing system.
Graphical optimization (GrO) is a common method for high-dose-rate/pulsed-dose-rate (PDR) prostate brachytherapy treatment planning. New methods performing inverse optimization of the dose ...distribution have been developed over the past years. The purpose is to compare GrO and two established inverse methods, inverse planning simulated annealing (IPSA) and hybrid inverse treatment planning and optimization (HIPO), and one new method, enhanced geometric optimization-interactive inverse planning (EGO-IIP), in terms of speed and dose-volume histogram (DVH) parameters.
For 26 prostate cancer patients treated with a PDR brachytherapy boost, an experienced treatment planner optimized the dose distributions using four different methods: GrO, IPSA, HIPO, and EGO-IIP. Relevant DVH parameters (prostate-V100%, D90%, V150%; urethra-D(0.1cm3) and D(1.0cm3); rectum-D(0.1cm3) and D(2.0cm3); bladder-D(2.0cm3)) were evaluated and their compliance to the constraints. Treatment planning time was also recorded.
All inverse methods resulted in shorter planning time (mean, 4-6.7 min), as compared with GrO (mean, 7.6 min). In terms of DVH parameters, none of the inverse methods outperformed the others. However, all inverse methods improved on compliance to the planning constraints as compared with GrO. On average, EGO-IIP and GrO resulted in highest D90%, and the IPSA plans resulted in lowest bladder D2.0cm3 and urethra D(1.0cm3).
Inverse planning methods decrease planning time as compared with GrO for PDR/high-dose-rate prostate brachytherapy. DVH parameters are comparable for all methods.
The American child welfare system intrudes on, separates, and permanently severs Black and Indigenous families at significantly higher rates than white families. It is profoundly troubling that the ...well-established harms associated with taking children from their homes are inflicted disproportionately on families of color. In light of the long and shameful American history of separating non-white children from their families, child welfare professionals have begun addressing racial bias in decision-making. But implicit bias training (the favored response of child welfare agencies) and efforts to make policies colorblind are not enough. True redress of the longstanding racial harms of the child welfare system requires scrutinizing the legal rules that too often stack the deck against innocent parents. Often the legal rules that cause the most harm have no explicit markers of racism. Because one of the critical aspects of addressing structural racism is recognizing that it is embedded in ways that make racist outcomes appear to be the result of neutral processes, we must vigorously reassess existing legal doctrine that disproportionately harms non-white litigants.
To compare five inverse treatment plans with one conventional manually-optimized plan for cervical cancer brachytherapy (BT) using radiobiological parameters combined with dosimetric and volumetric ...parameters.
Five inverse treatment plans were calculated using an inverse planning simulated annealing (IPSA) algorithm for each of four fractions for 12 cervical cancer patients treated with high-dose-rate (HDR) brachytherapy. The inverse treatment plans were compared to a manually-optimized plan used for the actual treatment of the patients. The comparison of the plans was performed with respect to the probability of cure without complication (P+).
Overall, the manually optimized plan scored the best results; however, the probability of cure without complication is within an acceptable clinical range for all the plans.
Although there are still considerable uncertainties in the radiobiological parameters, the radiobiological plan evaluation method presents itself as a potential complement to physical dosimetric methods.
Inverse planning simulated annealing (IPSA) optimized brachytherapy treatment plans are characterized with large isolated dwell times at the first or last dwell position of each catheter. The ...potential of catheter shifts relative to the target and organs at risk in these plans may lead to a more significant change in delivered dose to the volumes of interest relative to plans with more uniform dwell times.
This study aims to determine if the Nucletron Oncentra dwell time deviation constraint (DTDC) parameter can be optimized to improve the robustness of high-dose-rate (HDR) prostate brachytherapy plans to catheter displacements. A set of 10 clinically acceptable prostate plans were re-optimized with a DTDC parameter of 0 and 0.4. For each plan, catheter displacements of 3, 7, and 14 mm were retrospectively applied and the change in dose volume histogram (DVH) indices and conformity indices analyzed.
The robustness of clinically acceptable prostate plans to catheter displacements in the caudal direction was found to be dependent on the DTDC parameter. A DTDC value of 0 improves the robustness of planning target volume (PTV) coverage to catheter displacements, whereas a DTDC value of 0.4 improves the robustness of the plans to changes in hotspots.
The results indicate that if used in conjunction with a pre-treatment catheter displacement correction protocol and a tolerance of 3 mm, a DTDC value of 0.4 may produce clinically superior plans. However, the effect of the DTDC parameter in plan robustness was not observed to be as strong as initially suspected.
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