Target Delineation Research Articles

Recent strategies in target identification of natural products: Exploring applications in chronic inflammation and beyond.

Natural products are a treasure trove for drug discovery, especially in the areas of infection, inflammation and cancer, due to their diverse bioactivities and complex, and varied structures. Chronic inflammation is closely related to many diseases, including complex diseases such as cancer and neurodegeneration. Improving target identification for natural products contributes to elucidating their mechanism of action and clinical progress. It also facilitates the discovery of novel druggable targets and the elimination of undesirable ones, thereby significantly enhancing the productivity of drug discovery and development. Moreover, the rise of polypharmacological strategies, considered promising for the treatment of complex diseases, will further increase the demand for target deconvolution. This review underscores strategies for identifying natural product targets (NPs) in the context of chronic inflammation over the past 5 years. These strategies encompass computational methodologies for early target discovery and the anticipation of compound binding sites, proteomics-driven approaches for target delineation and experimental biology techniques for target validation and comprehensive mechanistic exploration.

AUDIT TO EVALUATE CURRENT RADIOTHERAPY (RT) PLANNING PATHWAY: COULD CURRENT PRACTICE BE IMPROVED BY THE TIMING OF MAGNETIC RESONANCE IMAGING (MRI)?

Abstract AIMS To evaluate the current guidance for glioblastoma (GBM) and primary brain radiotherapy (RT) planning. Current practice in this centre utilises pre and post-surgical MRI for RT target delineation. This study aims to explore the practicality and impact of scheduling an RT planning-specific MRI no more than 2 weeks before RT treatment start date (TSD). Time from surgery to RT TSD will also be explored. METHOD Fifty GBM patients, treated between August 2022 and October 2023, were audited retrospectively. Included patients were treated with radical intent and must have had surgery or biopsy. Age, gender or performance status (PS) were excluded from audit criteria. Age of MRI used for RT planning and surgery to TSD was noted. RESULTS Early results showed that the average age of MRI used for RT planning was 7 weeks old and Surgery to TSD was 7 weeks. A new pathway was introduced after 37 patients as these results were considered unacceptable. The new pathway included 1 reserved MRI appointment and one reserved RT Mask/CT appointment per week. 13 patients’ pathways were audited after introduction of the new pathway. The results showed that the average age of MRI used for RT planning was 2 weeks old and surgery to TSD was 6 weeks. CONCLUSION Limitations of the audit included disparity between number of patients before and after introduction of the new pathway. This was because of the time limitation for completion of the study. Improvement was seen in timing of MRI to TSD. However, the small improvement in timing of surgery to TSD was impacted by human factors rather than organisational influence, for example, surgical deconditioning, delays for wound healing and patient choice. This study has shown that the ideal timing of MRI can be achieved.

The Implementation of a MOOC-Based Flipped Classroom Teaching Method in the Context of Oncology Radiotherapy Residency Training.

The objective of this study is to examine the efficacy of the flipped classroom blended teaching method in the context of massive open online courses (MOOCs) for implementing standardized training and teaching of residents in oncology radiotherapy. A total of 48 junior residents who received standardized training at the Oncology Radiology Department of Harbin Medical University Cancer Hospital between September 2021 and August 2023 were randomly divided into two groups-i.e., the research group (24 cases) and the control group (24 cases)-using the random number table method. The control group received conventional didactic training, whereas the research group participated in a blended learning approach based on the MOOC model. The assessment results, along with the evaluations of teaching effectiveness, self-learning ability, and teaching satisfaction questionnaires, were observed and compared for the two groups of students. Compared with the control group, the research group presented significantly higher scores on theoretical foundations, skill operation, and case analysis (P < 0.05). The research group also showed greater outcomes than the control group in terms of improved theoretical knowledge, problem-solving skills, self-learning ability, teamwork, and communication (P < 0.05). The students in the research group presented significantly higher scores on measures of self-motivation beliefs, task analysis, self-monitoring and adjustment, and self-evaluation than those in the control group (P < 0.05). The research group also demonstrated significantly higher levels of satisfaction than the control group in terms of improvements in learning interest and initiative, clinical thinking ability, problem-solving ability, team cooperation ability, and the level of radiotherapy target delineation (P < 0.05). The implementation of MOOC-based flipped classroom blended teaching was shown to have positive effects on the standardized training and teaching of residents in the field of oncology radiotherapy. This approach can undoubtedly enhance students' academic performance, problem-solving abilities, and self-learning aptitudes while effectively stimulating their learning interests and initiative. Therefore, MOOC-based flipped classroom blended teaching is a valuable candidate for clinical application and promotion.

ESTRO-EANO guideline on target delineation and radiotherapy for IDHmutant WHO CNS grade 2 and 3 diffuse glioma

PurposeThis guideline will discuss radiotherapeutic management of IDH mutant grade 2 and grade 3 diffuse glioma, using the latest 2021 WHO (5th) classification of brain tumours focusing on: imaging modalities, tumour volume delineation, irradiation dose and fractionation. MethodsThe ESTRO Guidelines Committee, CNS subgroup, nominated 15 European experts who identified questions for this guideline. Four working groups were established addressing specific questions concerning imaging, target volume delineation, radiation techniques and fractionation. A literature search was performed, and available literature was discussed. A modified two-step Delphi process was used with majority voting resulted in a decision or highlighting areas of uncertainty. ResultsKey issues identified and discussed included imaging needed to define target definition, target delineation and the size of margins, and technical aspects of treatment including different planning techniques such as proton therapy. ConclusionsThe GTV should include any residual tumour volume after surgery, as well as the resection cavity. Enhancing lesions on T1 imaging should be included if they are indicative of residual tumour. In grade 2 tumours, T2/FLAIR abnormalities should be included in the GTV. In grade 3 tumours, T2/FLAIR abnormalities should also be included, except areas that are considered to be oedema which should be omitted from the GTV. A GTV to CTV expansion of 10 mm is recommended in grade 2 tumours and 15 mm in grade 3 tumours. A treatment dose of 50.4 Gy in 28 fractions is recommended in grade 2 tumours and 59.4 Gy in 33 fractions in grade 3 tumours. Radiation techniques with IMRT are the preferred approach.

Optimizing target and diaphragmatic configuration, and dosimetric benefits using continuous positive airway pressure in stereotactic ablative radiotherapy for lung tumors.

This study aimed to evaluate the impact of facilitating target delineation of continuous positive airway pressure (CPAP) in patients undergoing stereotactic ablative radiation therapy (SABR) for lung tumors by lung expansion and respiratory motion management. We performed a prospective single-institutional trial of patients who were diagnosed with either primary lung cancer or lung metastases and received SABR with a dose of 40 to 60 Gy in 4 fractions. Four-dimensional computed tomography simulations were conducted for each patient: once without CPAP and again with CPAP. Thirty-two patients with 39 tumors were analyzed, after the withdrawal of five patients due to discomfort. For 26 tumors separated from the diaphragm, CPAP significantly increased the superoinferior distance between the tumor and the diaphragm (5.96 cm vs. 8.06 cm; p < 0.001). For 13 tumors located adjacent to the diaphragm, CPAP decreased the overlap of planning target volume (PTV) with the diaphragm significantly (6.32 cm3 vs. 4.09 cm3; p = 0.002). PTV showed a significant reduction with CPAP (25.06 cm3 vs. 22.52 cm3, p = 0.017). In dosimetric analyses, CPAP expanded lung volume by 58.4% with a significant reduction in mean dose and V5 to V40. No more than grade 2 adverse events were reported. This trial demonstrated significant improvement of CPAP in target delineation uncertainties for lung SABR, with dosimetric benefits, a favorable safety profile and tolerability. Further investigation is warranted to explore the role of CPAP as a novel strategy for respiratory motion management.

The Systemic Inflammation Response Index Efficiently Discriminates between the Failure Patterns of Patients with Isocitrate Dehydrogenase Wild-Type Glioblastoma Following Radiochemotherapy with FLAIR-Based Gross Tumor Volume Delineation.

The objective of this study was to assess the connection between the systemic inflammation response index (SIRI) values and failure patterns of patients with IDH wild-type glioblastoma (GB) who underwent radiotherapy (RT) with FLAIR-based gross tumor volume (GTV) delineation. Seventy-one patients who received RT at a dose of 60 Gy to the GTV and 50 Gy to the clinical target volume (CTV) and had documented recurrence were retrospectively analyzed. Each patient's maximum distance of recurrence (MDR) from the GTV was documented in whichever plane it extended the farthest. The failure patterns were described as intra-GTV, in-CTV/out-GTV, distant, and intra-GTV and distant. For analytical purposes, the failure pattern was categorized into two groups, namely Group 1, intra-GTV or in-CTV/out-GTV, and Group 2, distant or intra-GTV and distant. The SIRI was calculated before surgery and corticosteroid administration. A receiver operating characteristic (ROC) curve analysis was used to determine the optimal SIRI cut-off that distinguishes between the different failure patterns. Failure occurred as follows: intra-GTV in 40 (56.3%), in-CTV/out-GTV in 4 (5.6%), distant in 18 (25.4%), and intra-GTV + distant in 9 (12.7%) patients. The mean MDR was 13.5 mm, and recurrent lesions extended beyond 15 mm in only seven patients. Patients with an SIRI score ≥ 3 demonstrated a significantly higher incidence of Group 1 failure patterns than their counterparts with an SIRI score < 3 (74.3% vs. 50.0%; p = 0.035). The present results show that using the SIRI with a cut-off value of ≥3 significantly predicts failure patterns. Additionally, the margin for the GTV can be safely reduced to 15 mm when using FLAIR-based target delineation in patients with GB.

Abdominal MR Multitasking for radiotherapy treatment planning: A motion-resolved and multicontrast 3D imaging approach.

Radiotherapy treatment planning (RTP) using MR has been used increasingly for the abdominal site. Multiple contrast weightings and motion-resolved imaging are desired for accurate delineation of the target and various organs-at-risk and patient-tailored planning. Current MR protocols achieve these through multiple scans with distinct contrast and variable respiratory motion management strategies and acquisition parameters, leading to a complex and inaccurate planning process. This study presents a standalone MR Multitasking (MT)-based technique to produce volumetric, motion-resolved, multicontrast images for abdominal radiotherapy treatment planning. The MT technique resolves motion and provides a wide range of contrast weightings by repeating a magnetization-prepared (saturation recovery and T2 preparations) spoiled gradient-echo readout series and adopting the MT image reconstruction framework. The performance of the technique was assessed through digital phantom simulations and in vivo studies of both healthy volunteers and patients with liver tumors. In the digital phantom study, the MT technique presented structural details and motion in excellent agreement with the digital ground truth. The in vivo studies showed that the motion range was highly correlated (R2 = 0.82) between MT and 2D cine imaging. MT allowed for a flexible contrast-weighting selection for better visualization. Initial clinical testing with interobserver analysis demonstrated acceptable target delineation quality (Dice coefficient = 0.85 ± 0.05, Hausdorff distance = 3.3 ± 0.72 mm). The developed MT-based, abdomen-dedicated technique is capable of providing motion-resolved, multicontrast volumetric images in a single scan, which may facilitate abdominal radiotherapy treatment planning.

Impact of the Novel MRI Contrast Agent Gadopiclenol on Radiotherapy Decision Making in Patients With Brain Metastases.

The aim of this study was to assess the effect of gadopiclenol versus gadobenate dimeglumine contrast-enhanced magnetic resonance imaging (MRI) on decision-making between whole-brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) for treatment of brain metastases (BMs). Patients with BMs underwent 2 separate MRI examinations in a double-blind crossover phase IIb comparative study between the MRI contrast agents gadopiclenol and gadobenate dimeglumine, both administered at 0.1 mmol/kg. The imaging data of a single site using identical MRI scanners and protocols were included in this post hoc analysis. Patients with 1 or more BMs in any of both MRIs were subjected to target volume delineation for treatment planning. Two radiation oncologists contoured all visible lesions and decided upon SRS or WBRT, according to the number of metastases. For each patient, SRS or WBRT treatment plans were calculated for both MRIs, considering the gross target volume (GTV) as the contrast-enhancing aspects of the tumor. Mean GTVs and volume of healthy brain exposed to 12 Gy (V12), as well as Dice similarity coefficient scores, were obtained. The Spearman rank (ρ) correlation was additionally calculated for assessing linear differences. Three different expert radiation oncologists blindly rated the contrast enhancement for contouring purposes. Thirteen adult patients were included. Gadopiclenol depicted additional BM as compared with gadobenate dimeglumine in 7 patients (54%). Of a total of 63 identified metastatic lesions in both MRI sets, 3 subgroups could be defined: A, 48 (24 pairs) detected equal GTVs visible in both modalities; B, 13 GTVs only visible in the gadopiclenol set (mean ± SD, 0.16 ± 0.37 cm3); and C, 2 GTVs only visible in the gadobenate dimeglumine set (mean ± SD, 0.01 ± 0.01). Treatment indication was changed for 2 (15%) patients, 1 from no treatment to SRS and for 1 from SRS to WBRT. The mean GTVs and brain V12 were comparable between both agents (P = 0.694, P = 0.974). The mean Dice similarity coefficient was 0.70 ± 0.14 (ρ = 0.82). According to the readers, target volume definition was improved in 63.9% of cases (23 of 36 evaluations) with gadopiclenol and 22.2% with gadobenate dimeglumine (8 of 36), whereas equivalence was obtained in 13.9% (5 of 36). Gadopiclenol-enhanced MRI improved BM detection and characterization, with a direct impact on radiotherapy treatment decision between WBRT and SRS. Additionally, a more exact target delineation and planning could be performed with gadopiclenol. A prospective evaluation in a larger cohort of patients is required to confirm these findings.

HYPCON trial: A phase II randomized study evaluating hypofractionated versus conventional adjuvant radiation therapy in head and neck malignancies.

143 Background: Hypofractionated RT has been established as standard of care at many cancer sites but there is limited data on use of hypofractionated RT for head and neck carcinomas (HNC). The HYPCON trial (CTRI/2023/02/049804) tested to reduce 10 fractions of PORT by delivery of hypofractionated PORT. Methods: Patients of HNC after radical surgery, with intermediate risk factors, were randomized based on site, T and N stage to either standard fractionation arm A (60Gy/30 fractions/6 weeks) or hypofractionated arm B (50Gy/20 fractions/4 weeks) in a 1:2 manner. The minimum sample size for the study was estimated based on a non-inferiority trial design as 120 considering a 10% clinical effectiveness margin and 5% attrition. Treatment allocation was done based on T stage, N stage &amp; HNC subsite. Target delineation included tumour bed with adequate margins (CTV_P) and microscopic lymph nodal (CTV_N) basin at risk. Organ delineation included all DARS. A double arc swallowing-sparing IMRT was used in both arms. The primary endpoint was locoregional control (LRC) at 1 year. Compliance, RT time (RTT), overall treatment time (OTT), progression-free survival (PFS) and overall survival (OS) were calculated in all patients. Acute &amp; late toxicities were recorded as per RTOG scale. Results: 135 patients were enrolled, 45 in Arm A &amp; 90 in Arm B. Majority of patients (96.9%) had oral cavity primary. Most of patients 74.8 % had early-stage disease. Compliance to PORT was 91.1% in Arm A versus 100% in Arm B. Median RTT for Arm A was 43 days (25-73 days) and 28 days (25-43 days) for Arm B (p&lt;0.0001). Median OTT in Arm A was 91 days (70-126 days) and 77 days (57-119 days) in Arm B (p&lt;0.0001). Median follow-up was 12.7 (2.73-23.87) months. One year, LRC was 72.9% vs 91.6% (p=0.007); PFS was 70.6% vs 90.5% (p=0.009) and OS was 88.7% vs 94.5% (p 0.02) Arm A versus Arm B respectively. Grade 3 or higher acute toxicity was seen in 39% in Arm A and 31.1% in Arm B (p=0.374). Grade 3 or higher late toxicity events were noted in 29.2% and 32.2% in arms A and B respectively (p= 0.671). Conclusions: Hypofractionated PORT reduced RTT &amp; OTT and was associated with improved treatment compliance, treatment outcomes (LRC, PFS, OS), and similar acute and late toxicity profile. This is the first study to demonstrate the superiority of hypofractionated compared to conventional PORT delivery for HNC. Clinical trial information: CTRI/2023/02/049804 .

238 Clinician experience with an AI-enhanced target delineation workflow: a mixed-methods pilot study

238 Clinician experience with an AI-enhanced target delineation workflow: a mixed-methods pilot study

Cardiac SABR: Image matching techniques for accurate treatment delivery

BackgroundVentricular tachycardia is an irregular heartbeat conventionally treated using invasive cardiac catheter ablation and medication. However, when standard treatments have been exhausted, cardiac SABR provides a final treatment option to this high-mortality condition. Complex diagnostic mapping and planning scans enable multi-disciplinary target delineation for a 25Gy single fraction. However, organs at risk (OAR) near the target make this treatment challenging to plan and deliver. Publications from cardiologists report the efficacy of cardiac SABR, however there is limited data on the treatment delivery and image matching of this complex procedure. MethodsFour specialist therapeutic radiographers experienced in cardiac SABR reviewed 40 CBCTs from 10 patients treated in the UK. Each therapeutic radiographer conducted five image matches: a manual match (manual), an automatic match to the heart structure (auto) and the auto match followed by manual adjustment to the PTV (PTV), all using three degrees of freedom (DoF) only. The auto and PTV matches were also repeated using 6DoF. Inter-observer variability was quantified using 95% limits of agreement from a modified Bland-Altman analysis. ResultsThe limits of agreement were smallest in the automatic matches suggesting the algorithm is reliable. A manual adjustment from the auto match to the PTV is clinically appropriate to optimise target coverage. The limits of agreement were smaller in the 6DoF PTV match 1.06 mm, 1.24 mm, 1.68 mm than the 3DoF PTV match 1.57 mm, 2.06 mm, 2.11 mm (lateral, vertical, longitudinal). ConclusionThe 6DoF CBCT image match has less variability and therefore suggest using a 6DoF couch for treatment delivery. Implications for practiceCardiac SABR CBCT image matching at treatment delivery is complex, optimisation of CBCT acquisition parameters and therapeutic radiographer training is essential prior to implementation.

AutoCorNN: An Unsupervised Physics-Aware Deep Learning Model for Geometric Distortion Correction of Brain MRI Images Towards MR-Only Stereotactic Radiosurgery.

Geometric distortions in brain MRI images arising from susceptibility artifacts at air-tissue interfaces pose a significant challenge for high-precision radiation therapy modalities like stereotactic radiosurgery, necessitating sub-millimeter accuracy. To achieve this goal, we developed AutoCorNN, an unsupervised physics-aware deep-learning model for correcting geometric distortions. Two publicly available datasets, the MPI-Leipzig Mind-Brain-Body with 318 subjects, and the Vestibular Schwannoma-SEG dataset, encompassing 242 patients were utilized. AutoCorNN integrates two 2D convolutional encoder-decoder neural networks with the forward physical model of MRI signal generation to predict undistorted MR and field map images from distorted MR input. The network is trained in an unsupervised manner by minimizing the mean absolute error between the measured and estimated k-space data, without requiring ground truth images during training or deployment. The model was evaluated on vestibular schwannoma cases. AutoCorNN achieved a peak signal-to-noise ratio (PSNR) of 41.35 ± 0.02dB, a root mean square error (RMSE) of 0.02 ± 0.003, and a structural similarity index (SSIM) of 0.99 ± 0.02 outperforming uncorrected and B0-mapping correction methods. Geometric distortions of about 1.6mm were observed at the air-tissue interfaces at the air canal and nasal cavity borders. Geometrically, distortion correction increased the target volume from 3.12 ± 0.52cc to 3.84 ± 0.54cc. Dosimetrically, AutoCorNN improved target coverage (0.96 ± 0.01 to 0.97 ± 0.02), conformity index (0.92 ± 0.03 to 0.94 ± 0.03), and reduced dose gradients outside the target. AutoCorNN achieves accurate geometric distortion correction comparable to conventional iterative methods while offering substantial computational acceleration, enabling precise target delineation and conformal dose delivery for improved radiation therapy outcomes.

Evaluating stereotactic accuracy with patient-specific MRI distortion corrections for frame-based radiosurgery.

This study examines how MRI distortions affect frame-based SRS treatments and assesses the need for clinical distortion corrections. The study included 18 patients with 80 total brain targets treated using frame-based radiosurgery. Distortion within patients' MRIs were corrected using Cranial Distortion Correction (CDC) software, which utilizes the patient's CT to alter planning MRIs to reduce inherent intra-cranial distortion. Distortion was evaluated by comparing the original planning target volumes (PTVORIG) to targets contoured on corrected MRIs (PTVCORR). To provide an internal control, targets were also re-contoured on uncorrected (PTVRECON) MRIs. Additional analysis was done to assess if 1mm expansions to PTVORIG targets would compensate for patient-specific distortions. Changes in target volumes, DICE and JACCARD similarity coefficients, minimum PTV dose (Dmin), dose to 95% of the PTV (D95%), and normal tissue receiving 12Gy (V12Gy), 10Gy (V10Gy), and 5Gy (V5Gy) were calculated and evaluated. Student's t-tests were used to determine if changes in PTVCORR were significantly different than intra-contouring variability quantified by PTVRECON. PTVRECON and PTVCORR relative changes in volume were 6.19%±10.95% and 1.48%±32.92%. PTVRECON and PTVCORR similarity coefficients were 0.90±0.08 and 0.73±0.16 for DICE and 0.82±0.12 and 0.60±0.18 for JACCARD. PTVRECON and PTVCORR changes in Dmin were -0.88%±8.77% and -12.9±17.3%. PTVRECON and PTVCORR changes in D95% were -0.34%±5.89 and -8.68%±13.21%. The 1mm expanded PTVORIG targets did not entirely cover 14 of the 80 PTVCORR targets. Normal tissue changes (V12Gy, V10Gy, V5Gy) calculated with PTVRECON were (-0.09%±7.39%, -0.38%±5.67%, -0.08%±2.04%) and PTVCORR were (-2.14%±7.34%, -1.42%±5.45%, -0.61%±1.93%). Except for V10Gy, all PTVCORR changes were significantly different (p<0.05) than PTVRECON. MRIs used for SRS target delineation exhibit notable geometric distortions that may compromise optimal dosimetric accuracy. A uniform 1mm expansion may result in geometric misses; however, the CDC algorithm provides a feasible solution for rectifying distortions, thereby enhancing treatment precision.

Optimized target delineation procedure for the radiosurgery treatment of ventricular tachycardia: observer-independent accuracy.

Part of the current stereotactic arrythmia radioablation (STAR) workflow is transfer of findings from the electroanatomic mapping (EAM) to computed tomography (CT). Here, we analyzed inter- and intraobserver variation in a modified EAM-CT registration using automatic registration algorithms designed to yield higher robustness. This work is based on data of 10 patients who had previously undergone STAR. Two observers participated in this study: (1) an electrophysiologist technician (cardiology) with substatial experience in EAM-CT merge, and (2) a clinical engineer (radiotherapy) with minimum experience with EAM-CT merge. EAM-CT merge consists of 3 main steps: segmentation of left ventricle from CT (CT LV), registration of the CT LV and EAM, clinical target volume (CTV) delineation from EAM specific points. Mean Hausdorff distance (MHD), Dice Similarity Coefficient (DSC) and absolute difference in Center of Gravity (CoG) were used to assess intra/interobserver variability. Intraobserver variability: The mean DSC and MHD for 3 CT LVs altogether was 0.92 ± 0.01 and 1.49 ± 0.23 mm. The mean DSC and MHD for 3 CTVs altogether was 0,82 ± 0,06 and 0,71 ± 0,22 mm. Interobserver variability: Segmented CT LVs showed great similarity (mean DSC of 0,91 ± 0,01, MHD of 1,86 ± 0,47 mm). The mean DSC comparing CTVs from both observers was 0,81 ± 0,11 and MHD was 0,87 ± 0,45 mm. The high interobserver similarity of segmented LVs and delineated CTVs confirmed the robustness of the proposed method. Even an inexperienced user can perform a precise EAM-CT merge following workflow instructions.

Integrating soil geochemistry and machine learning for enhanced mineral exploration at the dayu gold deposit, south China block

Combining traditional geochemical methods with advanced analytical techniques is a hallmark of contemporary exploration efforts. This study explores the intricate geological dynamics of the Dayu gold deposit, located in the Dayao Uplift of the South China Block. Using a multidisciplinary approach that includes soil geochemistry, conventional geochemical methods and advanced computational techniques such as machine learning and Discriminant Projection Analysis (DPA), we aim to uncover the deposit formation information. Our results reveal a complex pattern of element anomalies, which serve as a geochemical fingerprint of the Au mineralization processes that shaped the deposit over geological time. Principal Component Analysis (PCA) and cluster analysis on soil samples highlight significant correlation among Au and its pathfinder elements. By leveraging the predictive capabilities of machine learning algorithms, particularly Convolutional Neural Networks (CNN), we improve exploration strategies, enhance the precision of target delineation and guide sampling efforts. DPA further identifies distinct discriminant functions, aiding in group differentiation and providing insights into prospective mineralization zones. This study exemplifies the integration of traditional and innovative methodologies, offering a pathway to a deeper understanding of mineralization processes and improving the effectiveness of exploration in complex geological terrains. The findings advance our knowledge of the Dayu gold deposit and demonstrate the potential of these integrated approaches in similar geological settings.

Fundamentals of Targeted Integrative Program Development for Rural Labor Market Growth in Surplus Regions

This article introduces a systematic approach for developing a targeted comprehensive program aimed at enhancing the rural labor market (TCPDRLM) in labor-surplus regions of the Republic of Uzbekistan, within a socially oriented market economy. The paper outlines key interconnected principles for the development of TCPDRLM, including target orientation, complexity, integration, specificity, variability, realism, optimality, priority, delineation of powers and functions, limitations, targeting, controllability, and interconnectedness. Based on these principles, the article proposes interrelated sections for the program’s development, covering analytical and problematic aspects, target delineation, scientific and methodological frameworks, information management, modeling, software development, resource allocation, organizational and economic structuring, summary formulation, and legal considerations. Additionally, the article details the primary stages of TCPDRLM development, including setting objectives for the rural labor market (RLM), developing methodological and modeling frameworks for RLM analysis and forecasting, collecting statistical, marketing, and sociological data, compiling the TCPDRLM subprograms, obtaining approval for the RLM development program, and establishing organizational, economic, and legal mechanisms for program implementation and adjustment. The article's scientific contribution lies in the formulated methodology for TCPDRLM development in the rural labor market.

Stereotactic Body Radiation Therapy for Primary Renal Cell Carcinoma: A Case-Based Radiosurgery Society Practice Guide

Traditionally, renal cell carcinoma (RCC) was considered a radioresistant tumor, thereby limiting definitive radiation therapy management options. However, several recent studies have demonstrated that stereotactic body radiation therapy (SBRT) can achieve high rates of local control for the treatment of primary RCC. In the setting of expanding use of SBRT for primary RCC, it is crucial to provide guidance on practical considerations such as patient selection, fractionation, target delineation, and response assessment. This is particularly important in challenging scenarios where a paucity of evidence exists, such as in patients with a solitary kidney, bulky tumors, or tumor thrombus. The Radiosurgery Society endorses this case-based guide to provide a practical framework for delivering SBRT to primary RCC, exemplified by 3 cases. This article explores topics of tumor size and dose fractionation, impact on renal function and treatment in the setting of a solitary kidney, and radiation's role in the management of inferior vena cava tumor thrombus. Additionally, we review existing evidence and expert opinion on target delineation, advanced techniques such as magnetic resonance imaging guided SBRT, and SBRT response assessment.

A Pilot Clinical and Technical Validation of an Immersive Virtual Reality Platform for 3D Anatomical Modeling and Contouring in Support of Surgical and Radiation Oncology Treatment Planning.

The aim of this study was to validate a novel medical virtual reality (VR) platform used for medical image segmentation and contouring in radiation oncology and 3D anatomical modeling and simulation for planning medical interventions, including surgery. The first step of the validation was to verify quantitatively and qualitatively that the VR platform can produce substantially equivalent 3D anatomical models, image contours, and measurements to those generated with existing commercial platforms. To achieve this, a total of eight image sets and 18 structures were segmented using both VR and reference commercial platforms. The image sets were chosen to cover a broad range of scanner manufacturers, modalities, and voxel dimensions. The second step consisted of evaluating whether the VR platform could provide efficiency improvements for target delineation in radiation oncology planning. To assess this, the image sets for five pediatric patients with resected standard-risk medulloblastoma were used to contour target volumes in support of treatment planning of craniospinal irradiation, requiring complete inclusion of the entire cerebral-spinal volume. Structures generated in the VR and the commercial platforms were found to have a high degree of similarity, with dicesimilarity coefficient ranging from 0.963 to 0.985 for high-resolution images and 0.920 to 0.990 for lower resolution images. Volume, cross-sectional area, and length measurements were also found to be in agreement with reference values derived from a commercial system, with length measurements having a maximum difference of 0.22mm, angle measurements having a maximum difference of 0.04°, and cross-sectional area measurements having a maximum difference of 0.16 mm2. The VR platform was also found to yield significant efficiency improvements, reducing the time required to delineate complex cranial and spinal target volumes by an average of 50% or 29min.

Comparative Analysis of Recurrent Glioblastoma Target Contours via 11C-Methionine, 68Ga-Prostate-Specific Membrane Antigen Positron Emission Tomography, and Magnetic Resonance Imaging: Implications for Precision Radiotherapy Planning

PurposeGlioblastoma (GBM) recurrence poses challenges in radiotherapy treatment planning as reirradiation has limited leeway needing for precise target delineation. Though effective radiotracers are emerging for treatment planning, comparisons of 11C-methionine positron emission tomography (MET-PET), 68Ga-prostate-specific membrane antigen PET (PSMA-PET), and magnetic resonance imaging (MRI) for contouring recurrent GBMs are lacking in the literature. This case study aims to highlight the differences and similarities in target contours delineated from three examinations, aiming to raise doubts about the adequacy of current radiotherapy planning practices. Methods and MaterialsA 37-year-old female patient with recurrent IDH1/2 wild-type GBM underwent MRI, MET-PET, and PSMA-PET scans. Target delineations were performed, and volumes were compared using the Dice Similarity Coefficient (DSC), Conformity Index (CI), and Overlap Volume (OV), considering different planning target volume (PTV) margins. ResultsWe found that MET-PET and MRI volumes showed superior agreement compared to PSMA-PET across all similarity parameters, indicating a more marked discrepancy between PSMA-PET and other modalities. Increasing PTV margins demonstrated progressive convergence in inter-volume discrepancies. Notably, PSMA-PET delineated larger volumes extending beyond MRI-based volumes. ConclusionsThus, MRI alone may not suffice for target delineation in recurrent GBMs. PET imaging modalities offer complementary insights. Combined PET-MRI guidance could improve tumor boundary detection in target delineation for reirradiation. Prospective trials are necessary to ascertain its impact on patient outcomes.

Influence of intensity-modulated radiation therapy on long-term survival and late injury in patients with nasopharyngeal carcinoma after induction chemotherapy.

e24048 Background: To retrospectively analyze the effect of nasopharyngeal primary tumor (GTVnx) target delineation after induction chemotherapy on the long-term survival and late injury of patients after intensity-modulated radiotherapy, so as to provide a reference for the optimal treatment of nasopharyngeal carcinoma. Methods: Retrospective analysis was performed on 52 patients with nasopharyngeal carcinoma who underwent target delineation and radiotherapy after induction chemotherapy in our department from December 2011 to October 2013. All patients underwent long-term survival follow-up and analysis of late injury. The survival rate was calculated by Kaplan-Meier method and log-rank test, Univariate prognostic analysis was performed. Cox model was used to conduct multivariate prognostic analysis. The late radiation toxicity was Evaluation by RTOG/EORTC. Results: From December 2011 to October 2013,52 patients were enrolled in the study group. The follow-up period was up to December 2020. Among them, 23 patients died and the mortality rate was 44.23%, the recurrence rate was 0.38%. Serious adverse reactions occurred in 7 cases (13.2%). The 1,3,5,8 year survival rates were as follows: OS was 94.2%, 82.7%, 65.4%, 49.6%, LRFS was 96.2%, 82.7%, 63.5%, 46.2%, the survival rates of DMFS were 94.2%, 78.8%, 59.6% and 44.2%. Conclusions: The 5 and 8-years OS, LRFS and DMFS of NPC after induction chemotherapy patients treated with IMRT was relatively high, Distant metastasis was the main cause of treatment failure, The main late injuries include grade Ⅰ / Ⅱ hearing impairment, dysphagia dental, caries, xerostomia, the grade Ⅲ and Ⅳ late radiation injury was lower.