Optimal Radiation Dose Research Articles

Screening the optimal dose of gamma radiation for Tuta absoluta sterility: paving the way for sterile insect technique programs

Screening the optimal dose of gamma radiation for Tuta absoluta sterility: paving the way for sterile insect technique programs

Combination of proton- or X-irradiation with anti-PDL1 immunotherapy in two murine oral cancers

Combining radiation therapy with immunotherapy is a strategy to improve both treatments. The purpose of this study was to compare responses for two syngeneic head and neck cancer (HNC) tumor models in mice following X-ray or proton irradiation with or without immune checkpoint inhibition (ICI). MOC1 (immunogenic) and MOC2 (less immunogenic) tumors were inoculated in the right hind leg of each mouse (C57BL/6J, n = 398). Mice were injected with anti-PDL1 (10 mg/kg, twice weekly for 2 weeks), and tumors were treated with single-dose irradiation (5–30 Gy) with X-rays or protons. MOC2 tumors grew faster and were more radioresistant than MOC1 tumors, and all mice with MOC2 tumors developed metastases. Irradiation reduced the tumor volume in a dose-dependent manner. ICI alone reduced the tumor volume for MOC1 with 20% compared to controls, while no reduction was seen for MOC2. For MOC1, there was a clear treatment synergy when combining irradiation with ICI for radiation doses above 5 Gy and there was a tendency for X-rays being slightly more biologically effective compared to protons. For MOC2, there was a tendency of protons being more effective than X-rays, but both radiation types showed a small synergy when combined with ICI. Although the responses and magnitudes of the therapeutic effect varied, the optimal radiation dose for maximal synergy appeared to be in the order of 10–15 Gy, regardless of tumor model.

Wireless sequential dual light delivery for programmed PDT in vivo

Using photodynamic therapy (PDT) to treat deep-seated cancers is limited due to inefficient delivery of photosensitizers and low tissue penetration of light. Polymeric nanocarriers are widely used for photosensitizer delivery, while the self-quenching of the encapsulated photosensitizers would impair the PDT efficacy. Furthermore, the generated short-lived reactive oxygen spieces (ROS) can hardly diffuse out of nanocarriers, resulting in low PDT efficacy. Therefore, a smart nanocarrier system which can be degraded by light, followed by photosensitizer activation can potentially overcome these limitations and enhance the PDT efficacy. A light-sensitive polymer nanocarrier encapsulating photosensitizer (RB-M) was synthesized. An implantable wireless dual wavelength microLED device which delivers the two light wavelengths sequentially was developed to programmatically control the release and activation of the loaded photosensitizer. Two transmitter coils with matching resonant frequencies allow activation of the connected LEDs to emit different wavelengths independently. Optimal irradiation time, dose, and RB-M concentration were determined using an agent-based digital simulation method. In vitro and in vivo validation experiments in an orthotopic rat liver hepatocellular carcinoma disease model confirmed that the nanocarrier rupture and sequential low dose light irradiation strategy resulted in successful PDT at reduced photosensitizer and irradiation dose, which is a clinically significant event that enhances treatment safety.

Development of a sterile insect technique as a control strategy for the Asian citrus psyllid: establishing the effect of sterilizing X-rays on fecundity, fertility, and survival.

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a major pest of citrus due to its role as the vector of the bacterium that causes huanglongbing. In commercial citrus, ACP control currently relies on the application of insecticides, which may not be sustainable long-term, nor practical in urban areas. The sterile insect technique (SIT) is an alternative strategy in which large numbers of pests are reared, sterilized using radiation, and then released into the field to compete with wild individuals for matings, suppressing population growth. As a fundamental step toward the development of SIT for ACP, this study sought to identify the optimum radiation dose required to sterilize ACP without affecting their survival and mating capacity. Virgin adult ACP of both sexes were subjected to doses of X-ray irradiation ranging from 40 to 480 Gy, then paired with a nonirradiated mate and allowed to produce offspring. Fecundity was estimated as the number of eggs laid, and fertility as the proportion of those eggs that hatched. Females were more radio-sensitive than males, exhibiting a major drop in fecundity at even the lowest dose and 100% sterility at 80 Gy. In contrast, a fivefold higher dose (400 Gy) did not achieve complete sterility in males, with around 5% offspring survival. However, F1 progeny of males exposed to 320 Gy or higher were subsequently found to be 100% sterile. This confirmation of inherited sterility suggests that balancing the sterilizing effects of radiation against its mortality-inducing effects may warrant further evaluation.

Effect of arm position on image quality and radiation dose during thorax and abdomen computed tomography scans

IntroductionDuring Computed Tomography (CT) scans of the Thorax-Abdomen-Pelvis (TAP) the patient's arms should be positioned above the head to obtain optimal image quality and expose the patient to the lowest possible radiation dose. This may be impossible with patients with shoulder problems leading to arms being positioned in other ways. This study aimed to investigate differences in objective image quality and estimated effective dose (E), when positioning the arms below shoulder level in CT-TAP. MethodsAn anthropomorphic phantom with cadaver arms was used. Four arm positions were tested: Along the torso (A), on the pelvis (B), on a pillow on the pelvis (C), and one arm on pillow on the pelvis and the other arm on the pelvis (D). A Siemens SOMATOM Definition Flash CT-scanner with CareDose 4D was used. The dose length product was read to estimate E. Image quality was assessed objectively by measuring noise within the region of interest in the liver and urinary bladder. ResultsSignificant differences in E between all arm positions were seen (p = 0.005). The lowest E was obtained in position C, reducing E by 8.42%. Position A provided the best image quality but the highest E. ConclusionThis study showed no unequivocal optimal positioning of arms in CT-TAP. Position A provided the best object image quality, while position C yielded the lowest E. These results may impact the planning of diagnostic CT where positioning of arms may influence optimal image quality and radiation dose. Implication for practiceThis study illustrates tendencies for objective image quality and E when arms are positioned below shoulder level. Further research is needed to assess the clinical relevance with the diagnostic potential.

Total dose, fraction dose and respiratory motion management impact adrenal SBRT outcome

Purpose/Objective(s)Stereotactic body radiotherapy (SBRT) is an effective treatment for oligometastatic disease in multiple sites. However, the optimal radiation dose for long-term local control of adrenal metastases has yet to be determined. The aim of this study is to evaluate outcomes of adrenal SBRT and to evaluate factors that correlate with local control. Materials/MethodsAfter IRB approval, a retrospective data review of patients treated with SBRT for adrenal metastases at a medical center in Israel between 2015 and 2021 was conducted. A biological effective dose was calculated using an alpha beta ratio of 10. Kaplan Meier and Cox regression were calculated using SPSS software to describe the hazard ratio for local control and survival. Results83 cases of adrenal SBRT were identified. The average age was 67 (range 42–92 years old). Non-small cell lung cancer was the primary site in 44 % of patients. A total of 70 % of the patients had oligometastatic disease (less than five lesions), and the rest were polymetastatic, responding to systemic therapy with oligo progression in the adrenal. The average gross tumor volume (GTV) was 42 ml. Respiratory control was applied in 88 % of cases; 49.3 % used 4-D/ITV, and 38.5 % used breath-hold or continuous positive airway pressure (CPAP) with free breathing. On multivariable analysis, Dose above 75 Gy (biological effective Dose) (HR = 0.41, p = 0.031), Dose above 8 Gy per fraction (HR = 0.53p = 0.038), and breath-holds or CPAP (HR = 0.65, p = 0.047) were significant for local control. From multivariable analysis, we computed a predicted nomogram curve using seven clinical parameters to evaluate local control odds. ConclusionIn this single institution series reported to date, we found unilateral adrenal SBRT safe, yet bilateral treatment harbors a risk of adrenal insufficiency. Biological effective Dose > 75 Gy (BED), motion management with breath-hold or CPAP, and Dose per fraction > 8 Gy were the enhanced local controls. We propose a nomogram to help in decision-making regarding total Dose and Dose per fraction when treating adrenal SBRT.

Radiation Dose Optimization in Radiology: A Comprehensive Review of Safeguarding Patients and Preserving Image Fidelity.

Radiation dose optimization in radiology is a critical aspect of modern healthcare, aimed at balancing the necessity of diagnostic imaging with the imperative of patient safety. This comprehensive review explores the fundamental principles, techniques, and considerations in optimizing radiation dose to safeguard patients while preserving image fidelity. Beginning with acknowledging the inherent risks associated with medical radiation exposure, the review highlights strategies such as the As Low as Reasonably Achievable (ALARA) principle, technological advancements, and quality assurance measures to minimize radiation dose without compromising diagnostic accuracy. Regulatory guidelines and the importance of patient education and informed consent are also discussed. Through a synthesis of current knowledge and emerging trends, the review underscores the pivotal role of radiation dose optimization in radiology practice. Furthermore, it emphasizes the need for ongoing research and collaboration to advance dose reduction strategies, establish standards for radiation safety, and explore personalized dose optimization approaches. By prioritizing radiation dose optimization, healthcare providers can ensure the highest standards of patient care while minimizing potential risks associated with medical radiation exposure.

Advanced Computational Methods for Radiation Dose Optimization in CT.

In planning radiotherapy treatments, computed tomography (CT) has become a crucial tool. CT scans involve exposure to ionizing radiation, which can increase the risk of cancer and other adverse health effects in patients. Ionizing radiation doses for medical exposure must be kept "As Low As Reasonably Achievable". Very few articles on guidelines for radiotherapy-computed tomography scans are available. This paper reviews the current literature on radiation dose optimization based on the effective dose and diagnostic reference level (DRL) for head, neck, and pelvic CT procedures used in radiation therapy planning. This paper explores the strategies used to optimize radiation doses, and high-quality images for diagnosis and treatment planning. A cross-sectional study was conducted on 300 patients with head, neck, and pelvic region cancer in our institution. The DRL, effective dose, volumetric CT dose index (CTDIvol), and dose-length product (DLP) for the present and optimized protocol were calculated. DRLs were proposed for the DLP using the 75th percentile of the distribution. The DLP is a measure of the radiation dose received by a patient during a CT scan and is calculated by multiplying the CT dose index (CTDI) by the scan length. To calculate a DRL from a DLP, a large dataset of DLP values obtained from a specific imaging procedure must be collected and can be used to determine the median or 75th-percentile DLP value for each imaging procedure. Significant variations were found in the DLP, CTDIvol, and effective dose when we compared both the standard protocol and the optimized protocol. Also, the optimized protocol was compared with other diagnostic and radiotherapy CT scan studies conducted by other centers. As a result, we found that our institution's DRL was significantly low. The optimized dose protocol showed a reduction in the CTDIvol (70% and 63%), DLP (60% and 61%), and effective dose (67% and 62%) for both head, neck, and pelvic scans. Optimized protocol DRLs were proposed for comparison purposes.

An investigation of internal scatter during computed tomography using an anthropomorphic phantom

BackgroundThe general practice for all radiographic procedures is to use Lead Shielding to optimise radiation dose to the patient. The American Association of Physicists (AAPM) in Medicine in 2019 however, made a recommendation on the use of gonad and foetal shielding. The authors have noticed that very few papers on this topic come from developing countries, hence this study embarked on. The aim of our study was to evaluate internal scatter with Lead and without Lead Shielding in an anthropomorphic phantom during Computed Tomography of the brain, chest, abdomen, and pelvis.MethodsThe methodology was based on examinations of a RANDO phantom brain, chest, abdomen and pelvis on a General Electric Optima 660 scanner; which had a 128-channel multidetector row. Examinations were performed with Lead and without Lead Shielding equivalence of 0.35 mm, and the internal scatter measured using Thermoluminescent Dosimeters. The collected data was analysed descriptively to determine the mean and standard deviation. The T-tests and two-way analysis of variance (ANOVA) were used to compare the means.ResultsThe findings of this study revealed that internal scatter was highest closest to the exposed area with higher internal scatter observed for thicker areas of the phantom. Although slightly higher readings were recorded without Pb shielding, a non-statistical significance was observed for all internal scatter measurements regardless of whether Lead Shielding was used or not.ConclusionsA non-statistical significance for Computed Tomography examinations with and without Lead Shielding in confirmation with the AAPM positional statement.

Habitat escalated adaptive therapy (HEAT): a phase 2 trial utilizing radiomic habitat-directed and genomic-adjusted radiation dose (GARD) optimization for high-grade soft tissue sarcoma

BackgroundSoft tissue sarcomas (STS), have significant inter- and intra-tumoral heterogeneity, with poor response to standard neoadjuvant radiotherapy (RT). Achieving a favorable pathologic response (FPR ≥ 95%) from RT is associated with improved patient outcome. Genomic adjusted radiation dose (GARD), a radiation-specific metric that quantifies the expected RT treatment effect as a function of tumor dose and genomics, proposed that STS is significantly underdosed. STS have significant radiomic heterogeneity, where radiomic habitats can delineate regions of intra-tumoral hypoxia and radioresistance. We designed a novel clinical trial, Habitat Escalated Adaptive Therapy (HEAT), utilizing radiomic habitats to identify areas of radioresistance within the tumor and targeting them with GARD-optimized doses, to improve FPR in high-grade STS.MethodsPhase 2 non-randomized single-arm clinical trial includes non-metastatic, resectable high-grade STS patients. Pre-treatment multiparametric MRIs (mpMRI) delineate three distinct intra-tumoral habitats based on apparent diffusion coefficient (ADC) and dynamic contrast enhanced (DCE) sequences. GARD estimates that simultaneous integrated boost (SIB) doses of 70 and 60 Gy in 25 fractions to the highest and intermediate radioresistant habitats, while the remaining volume receives standard 50 Gy, would lead to a > 3 fold FPR increase to 24%. Pre-treatment CT guided biopsies of each habitat along with clip placement will be performed for pathologic evaluation, future genomic studies, and response assessment. An mpMRI taken between weeks two and three of treatment will be used for biological plan adaptation to account for tumor response, in addition to an mpMRI after the completion of radiotherapy in addition to pathologic response, toxicity, radiomic response, disease control, and survival will be evaluated as secondary endpoints. Furthermore, liquid biopsy will be performed with mpMRI for future ancillary studies.DiscussionThis is the first clinical trial to test a novel genomic-based RT dose optimization (GARD) and to utilize radiomic habitats to identify and target radioresistance regions, as a strategy to improve the outcome of RT-treated STS patients. Its success could usher in a new phase in radiation oncology, integrating genomic and radiomic insights into clinical practice and trial designs, and may reveal new radiomic and genomic biomarkers, refining personalized treatment strategies for STS.Trial registrationNCT05301283.Trial statusThe trial started recruitment on March 17, 2022.

Replace the Linear No-threshold Model with a Risk-informed Targeted Approach to Radiation Protection.

The linear no-threshold (LNT) model may be useful as a simple basis for developing radiation protection regulations and standards, but it bears little resemblance to scientific reality and is probably overly conservative at low doses and low dose rates. This paper is an appeal for a broader view of radiation protection that involves more than just optimization of radiation dose. It is suggested that the LNT model should be replaced with a risk-informed, targeted approach to limitation of overall risks, which include radiation and other types of risks and accidents/incidents. The focus should be on protection of the individual. Limitation of overall risk does not necessarily always equate to minimization of individual or collective doses, but in some cases it might. Instead, risk assessment (hazards analysis) should be performed for each facility/and or specific job or operation (straightforward for specialized work such as radiography), and this should guide how limited resources are used to protect workers and the public. A graded approach could be used to prioritize the most significant risks and identify exposure scenarios that are unlikely or non-existent. The dose limits would then represent an acceptable level of risk, below which no further reduction in dose would be needed. Less resources should be spent on ALARA and tracking small individual and collective doses. Present dose limits are thought to be conservative and should suffice in general. Two exceptions are possibly the need for a lower (lifetime) dose limit for lens of the eye for astronauts and raising the public limit to 5 mSv y -1 from 1 mSv y -1 . This would harmonize the public limit with the current limit for the embryo fetus of the declared pregnant worker. Eight case studies are presented that emphasize how diverse and complex radiation risks can be, and in some cases, chemical and industrial risks outweigh radiation risks. More focus is needed on prevention of accidents and incidents involving a variety of types of risks. A targeted approach is needed, and commitments should be complied with until they are changed or exemptions are granted. No criticism of regulators or nuclear industry personnel is intended here. Protection of workers and the public is everyone's goal. The question is how best to accomplish that.

Optimization of radiation doses for open lumbar spinal fusion using C-arm fluoroscopy and impact on radiation-induced cancer: a pilot study.

Intraoperative fluoroscopy use is essential during spinal fusion procedures. The amount of radiation dose should always be minimized. This study aimed to determine the feasibility of halving the frame rate from 12.5 to 6.25 frames per second (fps) and to quantify the reduction in the risk of developing radiation-induced cancer. This pilot study included 34 consecutive patients operated for open lumbar posterolateral fusion (PLF) with or without transforaminal lumbar interbody fusion (TLIF). C-arm modes were changed from half-dose (12.5 frames per second (fps), group I) to quarter-dose (6.25fps, group II). Age, body mass index, surgical procedure, number of treated levels, and complications were collected. Kerma area product (KAP), cumulative air kerma (CAK), and fluoroscopy time were compared. Effective dose and radiation-induced cancer risk were estimated. Eighteen and 16 patients were, respectively, included in group I and II. Demographic, surgical data, and fluoroscopy time were similar in both groups. However, CAK, KAP, and effective dose were significantly lower in group II, respectively, 0.56 versus 0.41mGy (p = 0.03), 0.09 versus 0.06Gycm2 (p = 0.04), and 0.03 versus 0.02mSv (p = 0.04). Radiation-induced cancer risk decreased by 47.7% from 1.49 × 10-6 to 7.77 × 10-7 after optimization. No complications were recorded in either group. This study demonstrates the feasibility of setting 6.25fps for TLIF with and without PLF. By halving the fps, radiation-induced cancer risk could be almost divided by two, without compromising surgical outcome. Finally, after optimization, the risk of developing radiation-induced cancer was less than one in a million.

Impact of implementing national diagnostic reference levels on radiation dose optimization in adult chest CT scans: a comparative analysis

The management and optimization of radiation dose in computed tomography (CT) examinations is of paramount importance, especially when the safety of patients is concerned. This study evaluated the effect of implementing national diagnostic reference levels (NDRLs) for radiation dose optimization in 1991 adult chest CT scans at a major Saudi hospital. Data was analyzed before and after NDRL implementation, with 21.5% of scans using contrast and 78.5% without. Before implementation, 11.1% used contrast and 36.7% did not; after implementation, 10.4% used contrast and 41.7% did not. The majority (83.5%) of scans passed NDRL criteria [CTDIvol and DLP are set at 12 (mGy) and 430 (mGy · cm)], with higher pass rates for contrast (91.8%) versus non-contrast (81.5%) scans. Effective dose (ED) was compared before and after NDRL implementation. For non-contrast scans, ED declined 2.43% from 12.37 ± 5.25 mSv to 12.07 ± 4.99 mSv after implementation (non-significant, p > 0.05). For contrast scans, ED declined more substantially, 6.77% from 9.6 ± 4.61 mSv to 8.95 ± 4.44 mSv (non-significant, p > 0.05). The findings highlight higher NDRL compliance in procedures with contrast and show areas for dose optimization improvement in procedures without contrast. Results suggest NDRLs provide guidance for optimizing radiation dose, but other factors like patient characteristics, protocol settings, and quality assurance programs should also be considered to ensure doses are as low as reasonably achievable (ALARA) without compromising diagnostic quality. Regular monitoring and review of CT protocols is recommended to avoid unintended consequences of dose reduction. Continued optimization is encouraged to reduce dose while ensuring quality.

Radiation exposure in routine mammography screening: a large observational cross-sectional study in Morocco

This observational cross-sectional study aims to assess the exposure levels during mammography examinations in Morocco and provide an international comparative analysis. Patient data from 1100 mammographic examinations conducted in five units, comprising both digital radiography (DR) and computed radiography (CR) systems from various brands and models in the Rabat-Salé-Zemmour-Zaër region, were collected. The mean glandular dose (MGD) and technical parameters, including exposure factors and breast thickness, were analyzed. The collected data were compared with findings from international studies to provide valuable context. The overall median MGD was 1.34 ± 0.36 mGy for craniocaudal (CC) and 1.48 ± 0.38 mGy for mediolateral oblique (MLO) incidences. It’s essential to note that these values were calculated based on the median compressed breast thickness. The MGD varied among different units and anode/filter combinations. The Rh/Rh anode/filter combination was most commonly used, resulting in the lowest radiation dose. The study findings also highlighted the relationship between MGD and breast thickness, with higher doses observed for thicker breasts. This study provides valuable insights into radiation exposure during mammography breast cancer screening in Morocco. The results underscore the importance of future dose optimization strategies to ensure patient safety without compromising diagnostic image quality. Implementing optimized technical parameters, conducting regular quality assurance programs, and promoting education and awareness are essential in achieving dose reduction and minimizing radiation risks. Collaboration among healthcare professionals, regulatory bodies, and international organizations is crucial for sharing best practices and advancing radiation dose optimization in mammography.

Evaluation of cultivated gladiolus varieties of Bangladesh and radio sensitivity test for varietal improvement

The study was conducted at the research field of Nalitabari Sub-station, BINA, Sherpur during the period November 2019 to May 2020 to characterize, evaluate and select promising gladiolus varieties suitable for Bangladesh and to determine the optimum dose of radiation for LD50 for varietal improvement. The parameters studies were plant height, days to 1st flowering, number of leaves per plant, leaf length, leaf breadth, length of spike, length of rachis, number of flower per spike, flower diameter, number of corms per plant, weight of single corm, vase life, per cent germination, per cent survivability, shoot length and root length. The longest plant (154.2 cm) was observed in White Prosperity, while the shortest plant (101.7 cm) was in Regency. The longest leaf (70.3 cm) was found in Red Cascade and the shortest leaf (48.0 cm) was found in Her Majesty. The highest number of floret per spike was produced by Red Cascade (17.3) followed by White Prosperity (17.0). The Regency produced the lowest number (8.0) of floret per spike. The longest vase life (9.3 days) was observed in American Beauty followed by (8.7 days) Red Cascade, while the shortest vase life (5.7 days) was recorded in Wine and Roses. In radio sensitivity test, 30-40 Gy of gamma irradiation would be the optimal dose for inducing useful mutation in gladiolus. Bangladesh J. Nuclear Agric, 37(2): 43-56, 2023

Dynamics of a diffusive model for cancer stem cells with time delay in microRNA-differentiated cancer cell interactions and radiotherapy effects

Understand the dynamics of cancer stem cells (CSCs), prevent the non-recurrence of cancers and develop therapeutic strategies to destroy both cancer cells and CSCs remain a challenge topic. In this paper, we study both analytically and numerically the dynamics of CSCs under radiotherapy effects. The dynamical model takes into account the diffusion of cells, the de-differentiation (or plasticity) mechanism of differentiated cancer cells (DCs) and the time delay on the interaction between microRNAs molecules (microRNAs) with DCs. The stability of the model system is studied by using a Hopf bifurcation analysis. We mainly investigate on the critical time delay τc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ au _{c}$$\\end{document}, that represents the time for DCs to transform into CSCs after the interaction of microRNAs with DCs. Using the system parameters, we calculate the value of τc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ au _{c}$$\\end{document} for prostate, lung and breast cancers. To confirm the analytical predictions, the numerical simulations are performed and show the formation of spatiotemporal circular patterns. Such patterns have been found as promising diagnostic and therapeutic value in management of cancer and various diseases. The radiotherapy is applied in the particular case of prostate model. We calculate the optimum dose of radiation and determine the probability of avoiding local cancer recurrence after radiotherapy treatment. We find numerically a complete eradication of patterns when the radiotherapy is applied before a time t<τc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$t < \ au _{c}$$\\end{document}. This scenario induces microRNAs to act as suppressors as experimentally observed in prostate cancer. The results obtained in this paper will provide a better concept for the clinicians and oncologists to understand the complex dynamics of CSCs and to design more efficacious therapeutic strategies to prevent the non-recurrence of cancers.

Factors associated with non-completion of palliative radiotherapy for spinal metastasis in patients with terminal cancer: a retrospective study.

Predictors of non-completion of radiotherapy (RT) should be identified to determine the optimal RT dose. Therefore, this study aimed to explore factors associated with non-completion of palliative RT in patients with terminal cancer. In this retrospective study, patients with terminal cancer who received RT (not including single-fraction RT) for relief of pain caused by spinal metastasis were categorized into complete and incomplete groups. Baseline characteristics, hematologic test data [e.g., total lymphocyte count (TLC)], performance status, palliative performance scale (PPS) score, psoas muscle index (PMI), Charlson comorbidity index, and age-adjusted Charlson comorbidity index of the patients were compared between the two groups. The complete group comprised 58 patients (median age: 68 years; female/male: 17/41; number of irradiation fractions: ≥2 to <10, 20 patients; 10, 34 patients; and >10, 4 patients), and the incomplete group comprised 9 patients (median age: 68 years; female/male: 3/6; number of irradiation fractions: ≥2 to <10, 2 patients; 10, 7 patients; and >10, 0 patient). The proportion of patient death within 1 week or 1 month was higher in the incomplete group than in the complete group. Compared with that in the incomplete group, TLC measured 1 week before RT (pre-TLC) and PMI recorded before RT were significantly higher in the complete group (P=0.013 and P=0.012, respectively). In multivariable analyses, pre-TLC was significantly associated with the incomplete group (P=0.048). Compared with the complete group, the incomplete group included several patients whose PPS scores rapidly decreased. Pre-TLC can predict non-completion of palliative RT in patients with terminal cancer.

Exploring sterile pollen technique as a novel tool for management of Palmer amaranth (Amaranthus palmeri)

AbstractThe success of the insect sterile technique (IST) in managing insect pests raised the hypothesis that a similar approach could be employed to control weed populations. Here, we investigated the feasibility of employing irradiated sterile pollen as a means to disrupt seed production in dioecious weeds, specifically focusing on Palmer amaranth (Amaranthus palmeri S. Watson). Our goal was to determine the optimal irradiation dose that strikes a balance between inducing sterility and preserving competitiveness, as excessive doses could result in pollen mortality, while low doses may retain fertility. Plants were grown in a greenhouse during the summer of 2020 and spring of 2021. Once they reached the flowering stage, male and female individuals were isolated. Mature pollen samples were collected and exposed to varying dosages (0, 100, 200, 300, 400, and 500 Gy) of gamma rays. These irradiated and non-irradiated pollen samples were used in pollen viability assessments and hand-pollination experiments. In the hand-pollination study conducted in 2020, we employed six pollination treatments using different irradiation doses. The results showed that 300 Gy was the most effective dose, resulting in a maximum reduction of 30% in seed set compared with open pollination when irradiated pollen had prior access to the stigma through artificial pollination before open pollination. In 2021, to simulate real field conditions, three additional treatments were introduced into the study, further confirming the effectiveness of the optimal 300 Gy dose. Our findings indicate that the sterile pollen technique (SPT) using irradiated pollen can be a valuable approach for reducing weed seed production. SPT also holds potential for broad-spectrum weed control by mixing sterile pollen from multiple weed species in a single application. Additionally, it could aid in managing herbicide-resistant weeds that have survived in-season control efforts. This research contributes to the development of novel and sustainable weed management strategies.

Exploring the impact of gamma rays and electron beam irradiation on physico-mechanical properties of polymers & polymer composites: A comprehensive review

Ionizing radiations are a unique and powerful means of modifying physico-mechanical properties of various polymers and composites. Modification of properties by irradiation technique has become a pioneer area of research due to its extraordinary results and toxic-free route. Many studies revealed that radiations act differently on polymers and composites. At the optimal radiation dose; various mechanical properties such as tensile, compression, impact and flexural strength/modulus were improved upto some extent. This paper gives a clear overview of different types of radiations used for altering the properties of polymers and its composites reinforced with natural and synthetic fillers. Furthermore, the current area of research has been documented in this review. In nutshell, high-energy gamma rays and electron beam act a promising technology and bettter alternative of traditionally used chemical methods to modify various chemical and physico-mechanical aspects of commerical available polymers and composites.

Near-Infrared Fluorescence Imaging Sensor with Laser Diffuser for Visualizing Photoimmunotherapy Effects under Endoscopy.

The drug efficacy evaluation of tumor-selective photosensitive substances was expected to be enabled by imaging the fluorescence intensity in the tumor area. However, fluorescence observation is difficult during treatments that are performed during gastrointestinal endoscopy because of the challenges associated with including the fluorescence filter in the camera part. To address this issue, this study developed a device that integrates a narrow camera and a laser diffuser to enable fluorescence imaging through a forceps port. This device was employed to demonstrate that a laser diffuser with an NIR fluorescence imaging sensor could be delivered through a 3.2 mm diameter port. In addition, fluorescence images of Cetuximab-IR700 were successfully observed in two mice, and the fluorescence intensity confirmed that the fluorescence decayed within 330 s. This device is expected to have practical application as a tool to identify the optimal irradiation dose for tumor-selective photosensitive substances under endoscopy.