Dose Parameters Research Articles

A review on functional lung avoidance radiotherapy plan for lung cancer

Lung cancer is the most common malignant tumor in China. Its incidence and mortality rate increase year by year. In the synthesis treatment of lung cancer, radiotherapy (RT) plays a vital role, and radiation-induced lung injury(RILI) has become the major limiting factor in prescription dose escalation. Conventional RT is designed to minimize radiation exposure to healthy lungs without considering the inhomogeneity of lung function, which is significantly non-uniform in most patients. In accordance with the functional and structural heterogeneity of lung tissue, functional lung avoidance RT (FLART) can reduce radiation exposure to functional lung (FL), thus reducing RILI. Meanwhile, a dose-function histogram (DFH) was proposed to describe the dose parameters of the optimized image-guided RT plan. This paper reviews lung function imaging for lung cancer RT plans. It also reviews the clinical applications of function-guided RT plans and their current problems and research directions to provide better guidance for clinical selection.

Permanent alopecia after radiotherapy of primary brain tumours: The most influential factors

PurposeAlopecia is a distressing side effect of radiotherapy in patients undergoing treatment for primary brain tumours. This study aimed to investigate the most influential clinical, demographic, and dosimetric factors associated with permanent scalp alopecia in patients with brain tumours treated with intensity-modulated radiations. Patients and methodsEighty patients with brain tumors treated with intensity-modulated radiations were enrolled. Inclusion criteria were having a primary brain tumour and patients with at least 18 months of radiotherapy. Scalp alopecia was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0. The scalp location with hair loss was marked and delineated on their follow-up MRI, and the planning dosimetric parameters, including D0.1cm3 (as maximum dose), mean dose, and various volumetric parameters such as V16Gy-43Gy (with about 5Gy interval) were recorded. In addition, receiver operating characteristic (ROC) curve analysis was employed to identify predictive parameters for chronic alopecia. ResultsThe hair loss severity was grade 1 for 70 % of cases, and grade 2 for 30 %. Male gender, history of chemotherapy, and family history of hair loss were significantly associated with increased volume of hair loss follicles. The correlation and ROC analysis revealed that regions receiving doses of 30Gy or higher (i.e., V30Gy) were associated with a higher risk of developing grade 2 alopecia. The resulting areas under the curve of 0.694 were indicators for moderate correlations between the considered dose–volume histogram parameters and patients’ permanent alopecia. Even if these results were not statistically significant, these findings suggest that specific dosimetric parameters, such as V30Gy to V43Gy, maybe the strongest predictors of grade 2 chronic radiation-induced alopecia. The cut-off values were also about 13.5 to 8 cm3 for V30Gy to V43Gy, respectively, which can be played as an indicator of the dose–volume histogram threshold above which permanent alopecia will be expected after brain intensity-modulated radiotherapy. ConclusionThe incidence of permanent alopecia after intensity-modulated radiotherapy is influenced by demographic, dosimetric, and clinical factors such as gender, history of chemotherapy, and family history, and the skull follicle regions receiving doses of 30Gy or higher.

The influence of cardiac substructure dose on survival in a large lung cancer stereotactic radiotherapy cohort using a robust personalized contour analysis

Background/Purpose: Radiation-induced cardiac toxicity in lung cancer patients has received increased attention since RTOG 0617. However, large cohort studies with accurate cardiac substructure (CS) contours are lacking, limiting our understanding of the potential influence of individual CSs. Here, we analyse the correlation between CS dose and overall survival (OS) while accounting for deep learning (DL) contouring uncertainty, a/b uncertainty and different modelling approaches. Materials/Methods: This single institution, retrospective cohort study includes 730 patients (early-stage tumours (I or II). All treated: 2009–2019), who received stereotactic body radiotherapy (≥5 Gy per fraction). A DL model was trained on 70 manually contoured patients to create 12 cardio-vascular structures. Structures with median dice score above 0.8 and mean surface distance (MSD) <2 mm during testing, were further analysed. Patientspecific CS dose was used to find the correlation between CS dose and OS with elastic net and random survival forest models (with and without confounding clinical factors). The influence of delineation-induced dose uncertainty on OS was investigated by expanding/contracting the DL-created contours using the MSD ± 2 standard deviations. Results: Eight CS contours met the required performance level. The left atrium (LA) mean dose was significant for OS and an LA mean dose of 3.3 Gy (in EQD2) was found as a significant dose stratum. Conclusion: Explicitly accounting for input parameter uncertainty in lung cancer survival modelling was crucial in robustly identifying critical CS dose parameters. Using this robust methodology, LA mean dose was revealed as the most influential CS dose parameter.

Optimising the Dose of Static Stretching to Improve Flexibility: A Systematic Review, Meta-analysis and Multivariate Meta-regression.

Static stretching is widely used to increase flexibility. However, there is no consensus regarding the optimal dosage parameters for increasing flexibility. We aimed to determine the optimal frequency, intensity and volume to maximise flexibility through static stretching, and to investigate whether this is moderated by muscle group, age, sex, training status and baseline level of flexibility. Seven databases (CINAHL Complete, Cochrane CENTRAL, Embase, Emcare, MEDLINE, Scopus, and SPORTDiscus) were systematically searched up to June 2024. Randomised and non-randomised controlled trials investigating the effects of a single session (acute) or multiple sessions (chronic) of static stretching on one or more flexibility outcomes (compared to non-stretching passive controls) among adults (aged ≥ 18years) were included. A multi-level meta-analysis examined the effect of acute and chronic static stretching on flexibility outcomes, while multivariate meta-regression was used to determine the volume at which increases in flexibility were maximised. Data from 189 studies representing 6654 adults (61% male; mean [standard deviation] age = 26.8 ± 11.4years) were included. We found a moderate positive effect of acute static stretching on flexibility (summary Hedges' g = 0.63, 95% confidence interval 0.52-0.75, p < 0.001) and a large positive effect of chronic static stretching on flexibility (summary Hedges' g = 0.96, 95% confidence interval 0.84-1.09, p < 0.001). Neither effect was moderated by stretching intensity, age, sex or training status, or weekly session frequency and intervention length (chronic static stretching only) [p > 0.05]. However, larger improvements were found for adults with poor baseline flexibility compared with adults with average baseline flexibility (p = 0.01). Furthermore, larger improvements in flexibility were found in the hamstrings compared with the spine following acute static stretching (p = 0.04). Improvements in flexibility were maximised by a cumulative stretching volume of 4min per session (acute) and 10min per week (chronic). Static stretching improves flexibility in adults, with no additional benefit observed beyond 4min per session or 10min per week. Although intensity, frequency, age, sex and training status do not influence improvements in flexibility, lower flexibility levels are associated with greater improvement following both acute and chronic static stretching. These guidelines for static stretching can be used by coaches and therapists to improve flexibility. PROSPERO CRD42023420168.

Is model-based dose calculation based on cone-beam computed tomography suitable for adaptive treatment planning in brachytherapy?

Model-based dose calculation considering tissue compositions is increasingly being investigated in brachytherapy. The aim of this study was to assess the suitability of modern cone-beam computed tomography (CBCT) imaging compared to conventional computed tomography (CT) scans for this purpose. By means of aphantom study, we evaluated the CT numbers and electron densities measured using amodern CBCT device as well as aconventional CT scanner for various materials. Based on this, we compared dose calculations (using the TG-43 formalism as well as model-based collapsed cone calculations assuming uniform materials [ACEuniform] and considering CT numbers [ACECT#]) on planning CTs and control CBCTs for patients with cervical and breast cancer as well as phantom-simulated skin cancer cases. Assessing dosimetric deviations between the planning CTs and control CBCTs acquired during the treatment course served to estimate interfractional implant variations. The comparison of ACEuniform-ACECT# deviations between planning CTs and control CBCTs revealed no statistically significant difference for almost all examined dose parameters. Dosimetric deviations between model-based dose calculations and TG-43 were partly significant but of small magnitude (< 10 cGy per fraction). Interfractional dosimetric variations were substantially larger than the dosimetric differences found between the various dose calculation procedures. Model-based dose calculation based on modern CBCT imaging was suitable. However, the found differences between these calculations and the TG-43 formalism should be investigated in dose-outcome analyses. The observed interfractional dosimetric variations revealed the importance of performing treatment quality assurance.

Impact of deep inspiration breath hold, surface-guided radiotherapy, and daily CBCT on the organs at risk in breast cancer radiotherapy

The goal of the study was to assess the impact of deep inspiration breath hold technique (DIBH), surface-guided radiotherapy (SGRT), and daily kilovoltage cone-beam computed tomography (kV-CBCT) on the dose to organs at risk (OAR) in left-sided breast cancer radiotherapy. Twenty-six consecutive left-sided breast cancer patients treated using Volumetric Intensity Modulated Arc Therapy (VMAT), DIBH, SGRT, and a hypofractionated regimen were retrospectively evaluated in this study. Dose parameters were extracted from dose-volume histograms (DVH). The Wilcoxon Matched Pairs test was used to test dose parameters obtained in free breathing (FB) and DIBH for statistical significance. Multivariable analysis of variance (ANOVA) and receiver operating characteristics (ROC) analysis were used to identify parameters and cut-off points associated with the reduction of the mean heart dose (MHD) by DIBH. Based on published models, the risk of cardiac and lung toxicity (pneumonitis) using SGRT or daily kV-CBCT was estimated and compared. DIBH substantially reduced the MHD (median, 43.6%; range, 4.2% to 75.1%; P < 0.00001). The risk of cardiac toxicity using SGRT increased by 1%, compared to 3.6% to 20.5% using daily kV-CBCT. No significant difference in the risk of radiation-induced pneumonitis using SGRT versus daily kV-CBCT was detected. The ANOVA revealed the relative increase of the left lung volume by DIBH as the only significant impact factor for the MHD. The ROC analysis of this parameter showed an area under the curve (AUC) of 0.89 (95%CI, 0.71 to 0.98; P < 0.0001). DIBH can substantially reduce the MHD in left-sided breast cancer patients treated with modern radiotherapy techniques and hypofractionation. Patient setup using SGRT compared to daily kV-CBCT may be the preferred option for many patients. In our patient cohort, the relative reduction of the left lung volume by DIBH can be used as a predictor to select patients who benefit from DIBH.

Radiation dose assessment of pediatric computed tomography of the chest: the need to consider patient size.

To evaluate the radiation dose of chest computed tomography (CT) examinations of pediatric patients and the extent to which volume CT dose index (CTDIvol) underestimates radiation dose in comparison to size specific dose estimates (SSDE). Single-center, retrospective study of consecutive unenhanced pediatric (age<18years) chest CTs between October 2015 and October 2016. Radiation dose as well as demographic and clinical data were recorded from 133 chest CTs. Patients were grouped into 4 categories based on mean effective diameter of the chest. SSDE was generated for each patient according to the water equivalent and effective diameter and compared to CTDIvol. Factors associated with higher radiation doses were assessed. CTDIvol underestimated radiation dose by 54.7%, 47.6%, 40.2%, and 31.2% (P<.001) for effective diameter groups 1 to 4, respectively, when compared to SSDE (calculated according to the water equivalent). When calculated according to the effective diameter, CTDIvol underestimated radiation dose by 47.6%, 39.4%, 27%, and 12.3% (P<.001) for effective diameter groups 1 to 4, respectively, when compared to SSDE. CT dose parameters, age, weight, Dw, and mean effective diameter were variables associated with higher radiation doses. CTDIvol systematically underestimated radiation dose in comparison to SSDE in pediatric patients submitted to chest CT and should not be used as the primary parameter to monitor CT protocols in these patients. SSDE calculated according to effective diameter also underestimates the radiation dose compared to SSDE calculated based on water equivalent.

ESTIMATION OF PATIENT RADIATION DOSE WITH SIZE SPECIFIC DOSE ESTIMATE (SSDE) METHOD IN ABDOMEN CT-SCAN EXAMINATION AT SEMEN GRESIK HOSPITAL

CT-Scan abdomen is an examination to see the anatomy and pathology of the abdominal organs, and the scanning image results are in the form of three-dimensional axial images of the body. The radiation dose released from the CT-Scan examination is more significant than other radiology modalities. Therefore, it is very important to estimate the patient's dose accurately. Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) are dose parameters used in CT-Scan to describe the dose value received by the patient. However, these parameters are the output of the CT-Scan, not as the dose received by the patient. The Size Specific Dose Estimate (SSDE) method based on AAPM Report No. 204 is used to determine the estimated dose received by the CT-Scan Abdomen patient. Calculations are done manually and with IndoseCT software. The data used are secondary data of 60 patients, namely 21 females and 39 males, who were on the CT-Scan Abdomen examination without contrast from the Instalasi Radiologi Rumah Sakit Semen Gresik. The SSDE value is obtained from the multiplication between the conversion factor and CTDIvol, where the conversion factor is an effective diameter function. The analysis examined the error value in manual calculations and IndoseCT software in men and women, the relationship between effective diameter and scanning radiation output (CTDIvol), and dose estimation estimates (SSDE). The difference in SSDE values between manual calculations and IndoseCT software was insignificant. The highest error value in women was 3% and 3.2% in men. Meanwhile, the relationship between effective diameter (Deff) and scanning radiation output (CTDIvol) and dose estimation estimates (SSDE) showed that the correlation between effective diameter (Deff) and CTDIvol showed a stronger correlation, namely with R2 around 0.7 in women and men, compared to the correlation between effective diameter (Deff) and SSDE with R2 around 0.03 in women and 0.2 in men. Keywords: CT-Scan, Abdomen, Size Specific Dose Estimate (SSDE).

Predictive Model of the Effects of Skin Phototype and Body Mass Index on Photobiomodulation Therapy for Orofacial Disorders

Monte Carlo techniques have been extensively used for planning laser-based clinical procedures such as photobiomodulation. However, the effects of several biological tissue characteristics regarding its morphological structure and physiological parameters have not been carefully addressed in many applications. Specifically, many questions remain concerning the effect of skin phototype and body mass index on the effectiveness of photobiomodulation for extraoral therapies. To address these questions, a Monte Carlo simulation model of the effects of body mass index-dependent skin structure on different Fitzpatrick skin types was developed, specifically tailored for the morphological characteristics of cheek tissue. The model describes the settings of a typical oral photobiomodulation treatment protocol for pain relief, namely the use of 660 nm and 808 nm laser wavelengths and a therapeutic dose of 2.0J/cm2 on the masseter muscle. The simulations were used to train a machine learning predictive model aimed at accelerating the treatment planning stage and assessing the importance of patient-specific parameters. A multiple-regression approach was adopted to predict muscle dose and treatment time for effective delivered dose. Body mass index had little effect on epidermal energy deposition, but an important impact on muscle dose parameters. Phototype also influenced muscle dose, but to a lesser extent than body mass index. The results of this study can be used to develop customized dosimetry phototherapy protocols to promote more effective and safe clinical outcomes.

Minimum cochlear dose impacts hearing after radiosurgery for sporadic vestibular schwannoma.

It is uncertain which cochlear dose parameters significantly impact hearing after stereotactic radiosurgery (SRS) for sporadic vestibular schwannoma (VS). The objective of this study was to determine the impact of cochlear dose parameters on hearing outcomes for patients with serviceable hearing (SH). This was a historical cohort study performed at a single tertiary center that included patients with sporadic VS and SH who underwent single-session Gamma Knife radiosurgery treatment from 2007 to 2022. Associations of cochlear dose parameters with time to non-SH and rates of change in pure-tone average (PTA) and word recognition score (WRS) following SRS were assessed. A total of 205 patients with SH underwent SRS for a sporadic VS. At SRS, 54 (26%) tumors were confined to the internal auditory canal and 151 (74%) extended into the cerebellopontine angle. At 2, 5, and 10 years following SRS, 62%, 37%, and 15% of patients maintained SH, respectively. The median time to non-SH was 1.8 years. The median rates of change in PTA and WRS were 6.0 dB of hearing loss per year and -6.5% per year, respectively. In a multivariable analysis, each 1-Gy increase in minimum cochlear dose was significantly associated with time to non-SH (HR 1.5, 95% CI 1.2-1.9), rate of change in PTA decibel hearing loss per year (parameter estimate [PE] 3.4, 95% CI 0.6-6.2), and rate of change in WRS percentage per year (PE -6.4, 95% CI -11.2 to -1.5). The associations of each 1-Gy increase in mean cochlear dose with hearing outcomes were only significant among patients with class B hearing (time to non-SH HR 1.3, 95% CI 1.1-1.6; rate of change in PTA PE 3.6, 95% CI 1.2-5.9; and rate of change in WRS PE -5.7, 95% CI -9.7 to -1.7). The minimum cochlear dose impacts hearing outcomes after SRS for VS and should be considered in radiosurgical treatment planning. In this cohort, the mean cochlear dose was only associated with hearing outcomes in the subgroup of patients with class B hearing at SRS.

Evaluating the Photocatalytic Activity of Green Synthesized Iron Oxide Nanoparticles

Water pollution from dyes is a major environmental challenge, demanding advanced materials for efficient degradation. In this study, we synthesized iron oxide nanoparticles (IONPs) using an aqueous extract of Senegalia catechu leaves and evaluated their photocatalytic activity in methylene blue (MB) dye degradation under sunlight irradiation. The IONPs were characterized by UV-visible spectroscopy (UV–vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). XRD pattern showed a highly crystalline structure with an average crystallite size of 34.7 nm, while SEM images revealed predominantly spherical particles with uneven surface texture. Photocatalytic efficiency exceeded 80% MB dye degradation after 120 min of sunlight exposure. Optimization of catalyst dose, pH, dye concentration, and other parameters is essential for maximizing degradation efficiency. The IONPs demonstrated reusability over four degradation cycles, retaining effective photocatalytic performance. This study underscores the potential of green-synthesized IONPs as eco-friendly photocatalysts for wastewater treatment and environmental remediation.

Development of a nomogram for predicting radiation‑induced pneumonia in patients with lung cancer undergoing close‑range radiotherapy with radioactive 125I particles.

The most common and potentially fatal side effect of postoperative radiotherapy using radioactive 125I particles in the chest is radiation-induced pneumonia (RP). The present study aimed to develop a nomogram to accurately predict RP in patients with lung cancer following this type of radiotherapy. A retrospective analysis was conducted on data from 436 patients with advanced lung cancer who underwent close-range radiotherapy using radioactive 125I particles at the General Hospital of Northern Theater Command from January 2016 to December 2023 (Shenyang, China). Risk factors for RP were identified through least absolute shrinkage and selection operator logistic regression and multivariable logistic regression analysis. These factors were then used to construct a dynamic nomogram. The predictive performance of the nomogram was validated using receiver operating characteristic (ROC) curves, calibration plots, and decision curve analysis. Additionally, the grading of RP and Kaplan-Meier analysis were performed. Preoperative N and M staging, the maximum dose and whether chemotherapy was administered were identified as significant predictors of RP. A dynamic nomogram for predicting RP was developed based on these risk factors. The area under the ROC curve was 0.878 (95% CI, 0.814-0.942) for the training cohort and 0.828 (95% CI, 0.787-0.870) for the validation cohort, indicating favorable discriminatory ability. The nomogram demonstrated excellent calibration. In both cohorts, the maximum dose parameter provided the most significant clinical benefits, supporting its promising clinical utility. Patients staged as T1 and T3 preoperatively were more likely to develop RP compared with those staged as T2 (P<0.001). Likewise, patients staged as M1 preoperatively, those receiving a maximum dose above the mean, and those who had undergone chemotherapy exhibited a higher probability of developing RP (P<0.001). The developed nomogram offers a precise and user-friendly tool for clinical application in predicting the risk of RP in patients with lung cancer undergoing close-range radiotherapy with radioactive 125I particles.

Implementing the optimized hippo-avoidance prophylactic cranial irradiation for limited-stage small cell lung cancer by tomotherapy and volumetric modulated arc therapy.

Hippo-avoidance prophylactic cranial irradiation (HA-PCI) requires a hippocampal avoidance zone expanded from hippocampus to ensure dose fall-off and compensate for setup errors. Most studies recommend a 5-mm margin, while it could be optimized to a 2-mm expansion. Here, we showed the details of optimized HA-PCI for limited-stage small cell lung cancer (LS-SCLC). This cohort study reviewed patients with LS-SCLC receiving optimized HA-PCI from August 2014 to June 2020 in the National Cancer Center of China. The hippo-related dose parameters were summarized. The comparison of the Hopkins Verbal Learning Test-Revised (HVLT-R) scores in different time points was conducted. The Kaplan-Meier method was used to calculate the survival rates. A total of 112 patients were included. The average doses of hippocampus and hippocampal avoidance zone were 6.80 Gy (IQR: 6.40-7.44) and 7.63 Gy (IQR: 7.14-8.39). No differences were observed in the two radiation techniques (tomotherapy [TOMO] vs. volumetric-modulated arc therapy [VMAT]). The decline of HVLT-R score remained in a low level and not significant in assessable patients (p = 0.095). With a median follow-up of 52 months (95% CI: 47.2-56.7), the 2-year overall survival and progression-free survival were 74.1% and 50.0%, respectively. Two intracranial recurrence lesions (2.3%) located <2 mm from the hippocampus. Optimized HA-PCI could achieve similar dose limitation by TOMO and VMAT techniques with favorable efficacy and minor toxicity.

Nanofibrous 3D scaffolds capable of individually controlled BMP and FGF release for the regulation of bone regeneration

The current clinical applications of bone morphogenetic proteins (BMPs) are limited to only a few specific indications. Locally controlled delivery of combinations of growth factors can be a promising strategy to improve BMP-based bone repair. However, the success of this approach requires the development of an effective release system and the correct choice of growth factors capable of enhancing BMP activity. Basic fibroblast growth factor (bFGF, also known as FGF-2) has shown promise in promoting bone repair, although conflicting results have been reported. Considering the complex biological activities of FGF-2, we hypothesized that FGF-2 can promote BMP-induced bone regeneration only if the dosage and kinetic parameters of the two factors are individually tailored. In this study, we conducted systematic in vitro studies on cell proliferation, differentiation, and mineralization in response to factor dose, delivery mode (sequential or simultaneous), and release rate. Subsequently, we designed individually controlled BMP-7 and FGF-2 release poly(lactide-co-glycolide) (PLGA) nanospheres attached to the poly(l-lactic acid) (PLLA) nanofibrous scaffolds. The data showed that BMP-7-induced bone formation was accelerated by a relatively higher FGF-2 dose (100 ng/scaffold) delivered at a faster release rate, or by a relatively lower FGF-2 dose (10 ng/scaffold) at a slower release rate in an in vivo bone regeneration model. In contrast, a very high dose of FGF-2 (1000 ng/scaffold) inhibited bone regeneration under all conditions. In vitro and in vivo data suggest that FGF-2 improved BMP-7-induced bone regeneration by coordinating FGF-2 dosage and release kinetics to enhance stem cell migration, proliferation, and angiogenesis. Statement of significanceBone morphogenetic proteins (BMPs) are the most potent growth/differentiation factors in bone development and regeneration. However, the clinical applications of BMPs have been limited to only a few specific indications due to the required supraphysiological dosages with the current BMP products and their side effects. Locally controlled delivery of BMPs and additional growth factors that can enhance their osteogenic potency are highly desired. However, different growth factors act with different mechanisms. Here we report a nanofibrous scaffold that mimics collagen in size and geometry and is immobilized with biodegradable nanospheres to achieve local and distinct release profiles of BMP7 and FGF2. Systematic studies demonstrated low dose BMP7 and FGF2 with different temporal release profiles can optimally enhance bone regeneration.

Evaluation of Radiation Pneumonitis in a Phase 2 Study of Consolidation Immunotherapy With Nivolumab and Ipilimumab or Nivolumab Alone Following Concurrent Chemoradiation Therapy for Unresectable Stage IIIA/IIIB Non-Small Cell Lung Cancer

Purpose/Objective(s)The addition of immunotherapy (IO) after concurrent chemoradiation (CCRT) for unresectable non-small cell lung cancer (NSCLC) has become common practice in eligible patients. Approaches to further improve outcomes and reduce treatment-related toxicity for these patients are needed. This study evaluates the risk of radiation pneumonitis after CCRT and its correlation with the radiation dose distribution, immunotherapy regimen (nivolumab vs nivolumab plus ipilimumab), and patient demographics across BTCRC-LUN16-081. Materials/MethodsPatients with unresectable stage III NSCLC after completion of CCRT were enrolled on BTCRC-LUN16-081, a randomized phase II trial to assess efficacy and tolerability of consolidative nivolumab versus nivolumab plus ipilimumab for six months. Radiation dose parameters, patient demographics, and toxicity events were evaluated among treatment arms for risk and severity of pneumonitis. ResultsOne-hundred and five patients were enrolled into two treatment arms, 54 patients received nivolumab alone and 51 patients received nivolumab plus ipilimumab. Of these, 104 patients had dose volume histogram (DVH) information available. Within this cohort, 65 patients (62.5%) had stage IIIA and 39 patients (37.5%) had stage IIIB NSCLC disease per AJCC 7th edition. During the study, 29 patients (27.9%) were diagnosed with grade 2 or greater pneumonitis. Utilizing logistic regression and evaluating different cut-offs for lung V20, patients with V20 >23% demonstrated significantly higher grade 2 or greater pneumonitis rates (37.1% vs. 16.2%, P = .031). No significant difference in rates of pneumonitis between arms were identified. Traditional lung DVH cut-offs (V5 of >65%, V20 of >35%, mean >20 Gy) were not associated with pneumonitis. ConclusionIn patients receiving nivolumab or nivolumab plus ipilimumab after definitive CCRT, lung V20 of >23% was associated with an increased risk of grade 2 or greater pneumonitis. Radiation dose constraints for lungs in patients receiving consolidative IO after CCRT should continue to be evaluated and optimized when feasible.

Optimization of the Adjustable Screw Dosing Parameters of a Grain Seeder Designed for Agricultural Dryland

Optimization of the Adjustable Screw Dosing Parameters of a Grain Seeder Designed for Agricultural Dryland

Particle Shape-Based Evaluation of the Leaching of Sphalerite Ore in Dilute Acid Solutions

In this study, the effects of changes in particle shapes on dissolution efficiencies in zinc (Zn) recovery from a lead-zinc (Pb-Zn) ore by acid leaching method were investigated. In the experiments with nitric acid (HNO3), sulfuric acid (H2SO4), and hydrochloric acid (HCl), particle size (75-106-150 µm), solids ratio (5-10-15-20-25%), leaching time (30-60-120-180-240 min), acid dosage (0.25-0.5-1-2-5 M) and pulp temperature (30-40-50-60-70 oC) parameters were analyzed. Optimum results were obtained under the conditions of 75 µm particle size, 15% solids ratio, 120 min leaching time, 0.5 M acid dosage, and 50°C pulp temperature for H2SO4; 106 µm particle size, 25% solids ratio, 60 min leaching time, 0.5 M acid dosage, and 70°C pulp temperature for HCl; 75 µm particle size, 20% solids ratio, 60 min leaching time, 1 M acid dosage, and 50°C pulp temperature for HNO3. As a consequence of the tests performed under these optimized conditions, 97.32%, 96.38% and 96.06% Zn dissolution efficiencies were obtained. Within the context of particle shape factor research, microscope images of the leaching residues were obtained from the experiments in which the pulp temperature, acid dosage, and leaching time parameters were examined. The samples obtained from the experiments with all three acids were compared with the ore samples, and the impacts of changes in circularity, roundness, and solidity values on dissolution efficiencies were interpreted.

Effect of diode pumping solid state laser with wavelength 589 nm on gene expression of interlukine-2 and interferon-γ in human T-lymphocytes.

To evaluate the impact of laser irradiation of human T-cell lymphocyte in culture to determine the photobiomodulatory effects of such irradiation on gene expression, and the release of growth factors and cytokines. The experimental study was conducted from November 2021 to April 2022 at the Postgraduate Anatomy Laboratory, Mustansiriyah University, Baghdad, Iraq, and comprised human blood samples T-cell lymphocytes were extracted and irradiated, followed by the extraction of ribonucleic acid to assess the effect of laser on gene expression of cytokines, interlukine-2 and interferon-gamma. A 589nm yellow light low-level laser beam from a diode pumping solid state laser was used at doses 30J/cm2, 50J/cm2 and 70J/cm2 for an exposure time of 15 minutes. Reverse transcriptase-polymerase chain reaction was used to measure gene expression. Data was analysed using GraphPad Prism 9. Cellular gene expression of the mediators changed significantly in response to laser irradiation at a variety of dosage parameters, and these effects depended on the wavelength and radiation exposure (p<0.05). The laser light may photobiomodulate the production of cytokines by human cells in vitro.

Is clinical target volume necessary for locally advanced non-small cell lung cancer treated with 4D-CT intensity-modulated radiation therapy

BackgroundA dosimetric evaluation is still lacking in terms of clinical target volume (CTV) omission in stage III patients treated with 4D-CT Intensity-Modulated Radiation Therapy (IMRT).Methods49 stage III NSCLC patients received 4D-CT IMRT were reviewed. Target volumes and organs at risk (OARs) were re-delineated. Four IMRT plans were conducted retrospectively to deliver different prescribed dose (74 Gy–60 Gy), and with or without CTV implementation. Dose and volume histogram (DVH) parameters were collected and compared.ResultsIn the PTV-g 60 Gy plan (PTV-g refers to the PTV generated from the internal gross tumor volume), only 5 of 49 patients had the isodose ≥ 50 Gy line covering at least 95% of the PTV-c (PTV-c refers to the PTV generated from the internal CTV) volume. When the prescribed dose was elevated to 74 Gy to the PTV-g, 33 of 49 patients could have the isodose ≥ 50 Gy line covering at least 95% of the PTV-c volume. In terms of OARs protection, the SIB-IMRT plan showed the lowest value of V5, V20, and mean dose of lung, had the lowest V55 of esophagus, and the lowest estimated radiation doses to immune cells (EDIC). The V20, V30, and mean dose of heart was lower in the simultaneous integrated boost (SIB) IMRT (SIB-IMRT) plan than that of the PTV-c 60 Gy plan.ConclusionsCTV omission was not suitable for stage III patients when the prescribed dose to PTV-g was 60 Gy in the era of 4D-CT IMRT. CTV omission plus high dose to PTV-g (74 Gy for example) warranted further exploration. The SIB-IMRT plan had the best protection to normal tissue including lymphocytes, and might be the optimal choice.

Dosimetric Evaluation of Hippocampus Sparing Intensity Modulated Radiation Therapy in Patients With Stage T1-T2 and Stage T3-T4 Nasopharyngeal Carcinoma

PurposeTo compare the hippocampus (HPC) dose reduced by HPC-sparing IMRT plans between nasopharyngeal carcinoma (NPC) patients of stages T1-T2 and T3-T4, and to investigate the correlation between the dose of the hippocampus and the volume of PTVnx70 (the planning target volume of the primary tumor in the nasopharynx received 70 Gy). Methods and MaterialsFifty-eight NPC patients were retrospectively evaluated. HPC non-sparing IMRT or sparing IMRT for each patient was designed according to the protocol for NPC. Dose-volume histogram (DVH) was used to evaluate the IMRT plans for each patient. The difference values of HPC parameters (e.g., Dmin[NS] - Dmin[S]) between HPC sparing and non-sparing plans in stage T1-T2 Group and stage T3-T4 Group were compared. The correlations between the dose of the hippocampus and the volume of PTVnx70 were analyzed. ResultsThere was no significance between HPC-sparing and non-sparing IMRT plans. Compared with the HPC non-sparing plans, the HPC sparing plans significantly decreased both dosimetric and volumetric parameters for the HPC (P < 0.05), except for Dmin, D98%, and V5. The medians of Dmedian[NS] - Dmedian[S], Dmean[NS] - Dmean[S], D40%[NS] - D40%[S], V30[NS] - V30[S], V40[NS] - V40[S] and V50[NS] - V50[S] in the T1-T2 Group were significantly lower than in the T3-T4 Group (P < 0.05), respectively. Both dosimetric and volumetric parameters for the HPC were positively correlated with the volume of PTVnx70 in HPC-sparing and non-sparing plans (P < 0.05). The volume of PTVnx70 was positively correlated with Dmedian[NS] - Dmedian[S], Dmean[NS] - Dmean[S], D40%[NS] - D40%[S], V40[NS] - V40[S] and V50[NS] - V50[S] (P < 0.05). ConclusionsHPC-sparing IMRT plans may play a more significant role in decreasing Dmedian, Dmean, D40%, and V30 ∼ V50 of HPC in NPC patients with stages T3-T4 than those in stages T1-T2. PTVnx70 volume of NPC patients are positively correlated with all dosimetric and volumetric parameters of HPC and the reduction of specific dosage parameters by HPC-sparing IMRT plans.