Irradiation Dose Research Articles

GCT-23. LONG-TERM FOLLOW-UP AND SURVIVALS OF PATIENTS WITH LOCALIZED CENTRAL NERVOUS SYSTEM NON-GERMINOMATOUS GERM CELL TUMORS (NGGCT) ENROLLED ON ACNS1123: A CHILDREN’S ONCOLOGY GROUP (COG) STUDY

Abstract BACKGROUND ACNS1123 was a Phase 2 study to determine whether irradiation could be safely reduced without impacting survival in a subgroup of NGGCT patients. METHODS Patients with localized disease who achieved a complete (CR) or partial response (PR) to induction chemotherapy were eligible to receive reduced dose/volume of irradiation to 30.6Gy whole ventricular field with 54Gy tumor-bed boost. RESULTS 107 eligible NGGCT patients were accrued. The median age of patients at enrollment was 11 years (3.7-21.6). Eighty patients (75%) were male. Location was pineal in 58 (55%), suprasellar in 37 (35%), ventricles in 6 (6%), and bifocal in 6 patients (6%). Sixty-six (61.7%) patients achieved a CR/PR post-induction and were eligible and evaluable for the primary objective and received reduced dose and volume of irradiation. Eight patients progressed; 6 had a distant spinal relapse (outside the irradiation field) and 2 had a local plus distant relapse. As of December 31, 2023, the median follow-up time for eligible and evaluable patients was 5.6 years (0.9-7.9) from enrollment. Except for an unrelated death due to SARS-CoV-2 at 5.5 years from enrollment, there were no grade 3 or higher adverse events at the 60-month follow-up timepoint and no disease progressions beyond 2 years. The 5-year progression-free and overall survival for all eligible and evaluable patients are 87.9% (95% CI:79%-94.8%) and 92.4% (95% CI:82.8%- 96.8%), respectively. CONCLUSION Although the study was closed prematurely due to the concern of increased spinal relapse, the current data suggest that most patients with localized NGGCT and a CR/PR to chemotherapy will survive long-term, and, in fact, have similar survival (PFS and OS) to patients enrolled on ACNS0122 who received full dose craniospinal irradiation. The key to future biologic studies and clinical trials is identifying at diagnosis those patients at high risk for relapse.

The effect of incidental dose to pelvic nodes in bladder-only irradiation in the era of IMRT: adosimetric study.

While three-dimensional radiotherapy (RT) causes high incidental nodal doses in bladder-only irradiation for muscle-invasive bladder cancer (MIBC), the impact on pelvic lymphatics is unclear in the era of intensity-modulated RT (IMRT). This study evaluates incidental doses to pelvic lymphatics in MIBC patients treated with IMRT. The data of 40MIBC patients treated with bladder-only IMRT and concurrent chemotherapy were retrospectively evaluated. The pelvic lymphatics were contoured on initial simulation images and incidental nodal doses were evaluated. The Statistical Package for the Social Sciences (SPSS) version23.0 (IBM, Armonk, NY, USA) was used for statistics. Median RT dose to the bladder was 60 Gy in 30fractions. In dosimetric analysis, median values of mean dose (Dmean) of the obturator, presacral, external iliac, internal iliac, and distal common iliac lymphatics were 33 Gy (range 4-50 Gy), 3 Gy (range 1-28 Gy), 9.5 Gy (range 3-41 Gy), 7.5 Gy (range 2-14 Gy), and 1 Gy (range 0-15 Gy), respectively. The Dmean of the obturator lymphatics was significantly higher (p < 0.001) and the Dmean of the distal common iliac lymphatics was significantly lower (p < 0.001) than all remaining lymphatic stations. The Dmean of the external iliac lymphatics was significantly higher than that of the presacral lymphatics (p < 0.001), but the difference with the internal iliac lymphatics was not statistically significant (p = 0.563). The incidental nodal doses with bladder-only IMRT are heterogeneous and remain below the generally accepted doses for microscopic disease eradication for bladder cancer.

GCT-18. GERMINOMAS OF THE CENTRAL NERVOUS SYSTEM (CNS): 20 YEARS EXPERIENCE WITH WHOLE VENTRICULAR IRRADIATION (WVI) AT FONDAZIONE IRCCS ISTITUTO NAZIONALE DEI TUMORI, MILAN

Abstract BACKGROUND Intracranial germ cell tumors account for 1-3% of pediatric CNS tumors, with germinomas constituting up to 65%, their prognosis being favourable compared to the non-germinomatous counterpart. METHODS After an unsuccessful experience with focal irradiation, from 2001 to 2021 we treated 68 patients (51 males/17 females, median age at diagnosis 16 years) with 4 PEB cycles (cisplatin 25 mg/sqm days 1-4, etoposide125 mg/sqm days 1-4, bleomycin 18 mg/sqm day 2, cycles every 21 days) followed by whole ventricular irradiation (WVI) 30,6 Gy/36Gy if CR/PR-SD. Patients with metastatic disease received craniospinal irradiation only (CSI 24 Gy+16Gy TB-tumor bed/WVI). RESULTS Fifty-nine patients had localized disease: 23 pineal, 22 suprasellar, 13 bifocal, 1 in the basal ganglia and 9 were metastatic. Suprasellar localization was associated with longer diagnostic delay. Five, 10 and 20 years OS and EFS were 100%, 97.5%, 97.5% and 95.3%, 92.8%.92.8% respectively. There was no statistical difference according to age at diagnosis, site and metastatic/bifocal disease. During follow-up 13/59 patients (22%) revealed moderate (2)/slight (11) impairment of the pulmonary function at spirometry assessment. Audiometric tests were available for 59 patients: 42 were normal (71%), 11 had a slight deficit, 4 moderate and 2 severe. Neurocognitive homogeneous evaluations were available only for 9 patients, so no clear correlation can be done, except observing the lowest scores in the patient with basal ganglia involvement. New endocrine deficits appeared in 9 patients after the treatment. CONCLUSIONS WVI tailored on response to chemotherapy proved effective in curing children CNS germinoma. Cisplatin and bleomycin-containing regimens induce high-response rates with known but in our experience limited sides effects. New collaborative protocols will investigate the reduction of the doses of irradiation and the use of less toxic drugs in order to achieve the same cure rates with less side effects.

EPID-04. CAUSES AND LONG-TERM COURSE OF OTOTOXICITY IN PEDIATRIC MEDULLOBLASTOMA AND EPENDYMOMA PATIENTS – CUMULATIVE PLATINUM AND COCHLEAR IRRADIATION DOSE MATTER

Abstract BACKGROUND Ototoxicity is a well-known side effect of treatment with platinum-containing chemotherapy and radiotherapy (RT). Nevertheless, precise dose-effect relationships are still lacking. METHODS Patients from the HIT2000 trial receiving first-line treatment for medulloblastoma (MB) or ependymoma (EPN) who were alive at last follow-up and had at least one audiogram prior to and after administration of chemotherapy with cisplatinum and radiotherapy were included into this study. Treatment details (incl. cochlear irradiation dose [CID]) and audiological outcome were analyzed. The ototoxicity was graded using the HIT scoring. RESULTS Courses of 101 patients were analyzed. Median audiology follow-up was 6 years [range: 1.0–18.1 years]. Ototoxicity grade ≥1 was documented for n=66 patients (65.4%). For n=27 this resulted in treatment modification. Univariable analyses revealed different proportions of ototoxicity (grade ≥1) regarding histology (CMB: 50/65, LCAMB: 3/3, DMB/MBEN: 8/12, EPN: 5/21; p&amp;lt;0.001), tumor location (supratentorial: 3/9, infratentorial: 63/92; p&amp;lt;0.001), metastatic status at diagnosis (M0: 46/77, M+: 20/24; p=0.003), radiation field (CSI: 59/75, local RT: 6/21, no RT: 1/5; p&amp;lt;0.001), CID (continuous variable, p=0.001) and cumulative cisplatinum dose (continuous variable, p&amp;lt;0.001). Certainly, disease specific parameters (histology/staging) were related to treatment intensity (cisplatinum/irradiation dose). Multivariable analyses confirmed the impact of cumulative cisplatinum dose (p=0.01) and CID (p=0.04). ROC-analyses allowed the definition of cut-offs for high risk of ototoxicity grade ≥1 (cisplatinum: 70mg/m2 BSA, CID: 37.5 Gy) and ototoxicity risk estimation, when applying doses above the respective cut-offs (cisplatinum dose increase by 1mg/m2 BSA results in 4% higher risk for ototoxicity grade ≥1; CID dose increase by 1 Gy results in 4.6% higher risk for ototoxicity grade ≥1). CONCLUSIONS Ototoxicity affects a majority of children receiving adjuvant treatment for MB and EPN. To avoid disabilities and negative effect on quality of live, dosage of cisplatinum and radiotherapy should be scrutinized and reduced whenever possible.

Grain boundary migration and mechanical properties altering in Fe – 10Ni – 20Cr alloy under irradiation

Mechanisms of ∑5(210)[001] and ∑5(310)[001] symmetrical tilled grain boundaries migration in bicrystall Fe – 10Ni – 20Cr samples under irradiation were investigated by means of molecular dynamics. The density of radiation defects grows quite quickly up to a dose of ~0.02 dpa and then reaches saturation. This is due to balancing of the radiation defects generation and annihilation rates. It is shown that at the early stage of irradiation, grain boundaries began to deviate stochastically from their initial positions due to interaction with cascades of atomic displacements and absorption of structural defects. During irradiation, the grain boundary region thickened and became rough. With an increase in the radiation dose, size of the clusters of point defects (tetrahedrons of stacking faults and dislocation loops) increased. Interaction with large clusters of point defects led to the formation of bends on initially flat surfaces of grain boundaries. At small distances between the boundaries, the high driving force between the curved surfaces of grain boundaries significantly increased the rates of their approach. The average migration rates of grain boundaries before their direct interaction with each other were approximately 0.8 m/s. As a result of their approach, the grain boundaries were annihilated, the potential energy of the sample decreased abruptly, and the grains merged. The annihilation of grain boundaries ∑5(310)[001] required twice the radiation dose compared to the grain boundary ∑5(210)[001]. The direct interaction of grain boundaries with each other abruptly increased the velocity of their migration due to the emergence of a driving force from the curved sections of the grain boundary surfaces. Influence of the radiation dose on deformation behavior features of the samples under uniaxial strains was studied. With an increase in the radiation dose, the elastic limit decreased rapidly and reached saturation at an irradiation dose of ~0.01 dpa.

A comparative study of the mechanical and thermal properties of EPDM rubber/cement kiln dust composite cured by ionizing radiation

In this work, cement kiln dust (CKD) will be studied as an unconventional filler for ethylene-propylene-diene terpolymer (EPDM) rubber as an alternative to silica, which is widely used as filler for many types of rubber. (EPDM)/CKD rubber composites were fabricated using ionizing radiation. EPDM rubber was blended with different portions of cement-kiln dust 5, 10, 15, 20, 25, and 30 phr (phr = parts per hundred rubber). The prepared composites were cured by exposing to different doses of gamma rays up to 150 kGy to enhance the crosslinking of the EPDM rubber. The thermo-mechanical properties of the EPDM/CKD and EPDM/Si composites were investigated as a function of irradiation dose. The results showed a significant improvement in elongation and tensile strength by incorporating cement dust into EPDM rubber up to 20 phr, which is not significantly different from composites incorporated with silica. Gamma irradiation significantly improved the properties of all formulations.

Nano-modifications of edible materials using ionizing radiation for potential application in active food safety

Active food packaging films from Carboxy methyl cellulose and starch (CMC-g-Starch) reinforced with Magnesium-oxide (MgO) NPs are created and characterized. The effect of different particle sizes, MgO NPs concentrations and different gamma irradiation doses on the preparation of (CMC-g-Starch-MgO) edible nanocomposite films were investigated to determine their properties. Several analytical methods, such as swelling behavior, FT-IR, TEM, TGA, and mechanical characteristics, are represented to investigate different characteristics of the prepared (CMC-g-Starch-MgO) edible nanocomposite films. Also, the prepared (CMC-g-Starch-MgO) edible nanocomposite films and their coating were subjected to the fresh Peaches fruits. Their effect on the Peach fruits' lifespan was evaluated. The anti-microbial property of the edible (CMC-g-Starch-MgO) nanocomposite films of gram (+ve) and gram (–ve) bacteria was reported. Results represented the thermal and mechanical characteristics of (CMC-g-Starch-MgO) edible nanocomposite films, which were enhanced by γ irradiation. Also, the irradiated (CMC-g-Starch-MgO) edible nanocomposite films and their coating extend the lifespan of Peaches fruits and exhibit resistance to pathogenic microorganisms. In conclusion, (CMC-g-Starch-MgO) edible nanocomposite films fulfilled the required behaviors for the application in the nanofood packaging era.

Defects analysis in low displacement damage neutron-irradiated austenitic stainless steels

Analysis of neutron irradiation-induced defects is carried out using Transmission Electron Microscope (TEM) on three variants of austenitic stainless steels, SS 304 L(N), SS 316 L(N), and SS 316 grid plate material irradiated in the Indian Fast Breeder Test Reactor at Kalpakkam to low displacement damage levels of 1.76–6.75 dpa at an irradiation temperature of 380 °C-400 °C and dpa rate in the order of 10−7dpa/s. There is a significant variation in the faulted dislocation loop size distribution and number density as a function of irradiation dose among these stainless steels due to their different stacking fault energies which is evident from the quantified defects data presented. At ∼5.08 dpa, SS 304 L(N), SS 316 L(N) and SS 316 exhibited faulted dislocation loop number densities of 2.3 × 1022/m3, 4.8 × 1021/m3, and 1.2 × 1022/m3 with mean loop sizes of 15.5 ± 6.3 nm, 35.4 ± 13.7 nm, and 16.1 ± 5.6 nm respectively. Thus, at an identical dpa level, SS 304 L(N) and SS 316 L(N) have the highest and the lowest faulted loop number densities respectively. The general size-distribution behaviour, the increment in the loop size with enhanced size distribution as a function of dpa is observed only for SS 316 L(N). The dislocation density data previously determined using X-ray diffraction analysis is correlated to the number density of dislocation loops along with their size distribution determined using TEM analysis. Finally, the change in the yield strength due to the increment in the faulted dislocation loop number density is determined.

Flexible Solid-Electrolyte-Gated-Dielectric Carbon Nanotube Thin Film Transistors and Integrated Circuits with the Recorded Radiation Tolerance and Reparability.

Radiation-tolerance and repairable flexible transistors and integrated circuits (ICs) with low power consumption have become hot topics due to their wide applications in outer space, nuclear power plants, and X-ray imaging. Here, we designed and developed novel flexible semiconducting single-walled carbon nanotube (sc-SWCNT) thin-film transistors (TFTs) and ICs. Sc-SWCNT solid-electrolyte-gate dielectric (SEGD) TFTs showcase symmetric ambipolar characteristics with flat-band voltages (VFB) of ∼0 V, high ION/IOFF ratios (>105), and the recorded irradiation resistance (up to 22 Mrad). Moreover, flexible sc-SWCNT ICs, including CMOS-like inverters and NAND and NOR logic gates, have excellent operating characteristics with low power consumption (≤8.4 pW) and excellent irradiation resistance. Significantly, sc-SWCNT SEGD TFTs and ICs after radiation with a total irradiation dose (TID) ≥ 11 Mrad can be repaired after thermal heating at 100 °C. These outstanding characteristics are attributed to the designed device structures and key core materials including SEGD and sc-SWCNT.

High adsorption of Cu(II) in novel thiacalix[4]arene/acrylic polymer/diatomite fast fabricated by electron beam irradiation: Controllable microstructures, adsorption performance and mechanism

Chemical grafting of calix[4]arene is a common method to prepare high-performance calix[4]arene adsorbents for heavy metals, however, the chemical grafting process consumes much time and a large amount of heating energy due to the tedious steps. Herein, a thiacalix[4]arene/acrylic polymer/diatomite (TC4A/PAA/diatomite) adsorbent was fast fabricated by electron beam irradiation induced grafting, polymerization and crosslinking technique only in one-pot for the removal of Cu(II) as an important form of heavy metal pollution. Characterization by Fourier transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), diffuse reflectance UV–visible spectra and positron annihilation lifetime spectra (PALS) disclosed that the eco-friendly and low-cost TC4A/PAA/diatomite irradiated at 90 kGy namely TC4A/PAA/diatomite (90 kGy) with strong complexing ability owing to many functional groups such as carboxyl, hydroxyl etc in it. The effects of electron beam irradiation dose, initial solution pH, and initial concentration of Cu(II) on the adsorption performance of TC4A/PAA/diatomite were investigated. The isotherm adsorption data of Cu(II) in TC4A/PAA/diatomite (90 kGy) are more suitable for the Langmuir model with the maximum adsorption capacity of 123.30 mg/g. In addition, the bifunctional TC4A/PAA/diatomite (90 k Gy) can efficiently remove Cu(II) and display excellent reusability properties. The adsorption mechanism was further analyzed by FTIR, SEM, X-ray photoelelctron spectroscopy (XPS), diffuse reflectance UV–visible spectra and PALS. This study provides a fast, efficient and eco-friendly synthesis method of calix[4]arene adsorbent, conducing to the design of material innovation. Meanwhile, TC4A/PAA/diatomite (90 kGy) has potential application prospects in the treatment of practical Cu(II) contaminated wastewater.

Еffect of Radiation Therapy on Breast Reconstruction in Breast Cancer Patients

Background. The surgical stage remains the main one in the combined and complex treatment of breast cancer. Radical mastectomy and reconstructive plastic surgery are the main option for surgical treatment of vast majority patients. Radiation therapy can lead to the development of complications after breast reconstruction, and vice versa, the reconstructed mammary gland can cause technical difficulties for the radiologist to properly adjust the required dose of irradiation. Aim — to choose the optimal method of breast reconstruction using various implants, as well as endoprostheses to minimize post-radiation complications and maintain a high level of quality of life for patients after breast cancer treatment. Methods. The retrospective study was conducted in the department of oncology and reconstructive plastic surgery of the breast and skin in the P.A. Herzen Moscow Research Oncology Institute from June 2013 to November 2017. There were performed 132 operations: 111 subcutaneous mastectomy with one-stage reconstruction with an endoprothesis and 21 mastectomy with a one-stage reconstruction with an endoprothesis. The distribution by stages: I — 57, IIA — 39, IIB — 17, IIIA — 13, IIIC 4; 2 cases of breast sarcoma. Prophylactic mastectomy of the contralateral gland was performed in 22 patients, mastopexy in 8, augmentation in 20. Polyurethane implants were applied in 82 cases (62%). Radiation therapy was performed in 47 patients with total dose 45 Gy. Bilateral reconstruction was performed in 22 patients. Results. The mean follow-up period was 28.44 ± 14.66 months (from 6 to 48 months). The most frequent complication in the postoperative period was the development of capsular contracture: seroma — 20 patients, hematoma — 2, edge necrosis — 6, protrusion — 6, infection — 2 patients. The most common capsular contracture by Baker was III degree, n = 18. The average period of development of capsular contracture was 7.6 ± 11.65 months. Conclusion. Despite the greater number of complications during the one-stage reconstruction, the implants remain in advantage in choosing a method of treating breast cancer by both the patient and the surgeon.

Geriatric assessment with management for older patients with cancer receiving radiotherapy: a cluster-randomised controlled pilot study

BackgroundGeriatric assessment and management (GAM) improve outcomes in older patients with cancer treated with surgery or chemotherapy. It is unclear whether GAM may provide better function and quality of life (QoL), or be cost-effective, in a radiotherapy (RT) setting.MethodsIn this Norwegian cluster-randomised controlled pilot study, we assessed the impact of a GAM intervention involving specialist and primary health services. It was initiated in-hospital at the start of RT by assessing somatic and mental health, function, and social situation, followed by individually adapted management plans and systematic follow-up in the municipalities until 8 weeks after the end of RT, managed by municipal nurses as patients’ care coordinators. Thirty-two municipal/city districts were 1:1 randomised to intervention or conventional care. Patients with cancer ≥ 65 years, referred for RT, were enrolled irrespective of cancer type, treatment intent, and frailty status, and followed the allocation of their residential district. The primary outcome was physical function measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (QLQ-C30). Secondary outcomes were overall quality of life (QoL), physical performance, use and costs of health services. Analyses followed the intention-to-treat principle. Study registration at ClinicalTrials.gov ID NCT03881137.ResultsWe included 178 patients, 89 in each group with comparable age (mean 74.1), sex (female 38.2%), and Edmonton Frail Scale scores (mean 3.4 [scale 0–17], scores 0–3 [fit] in 57%). More intervention patients received curative RT (76.4 vs 61.8%), had higher irradiation doses (mean 54.1 vs 45.5 Gy), and longer lasting RT (mean 4.4 vs 3.6 weeks). The primary outcome was completed by 91% (intervention) vs 88% (control) of patients. No significant differences between groups on predefined outcomes were observed. GAM costs represented 3% of health service costs for the intervention group during the study period.ConclusionsIn this heterogeneous cohort of older patients receiving RT, the majority was fit. We found no impact of the intervention on patient-centred outcomes or the cost of health services. Targeting a more homogeneous group of only pre-frail and frail patients is strongly recommended in future studies needed to clarify the role and organisation of GAM in RT settings.

Effectiveness of cell therapy of acute radiation syndrome in mice with intravenous and intraperitoneal administration of a cellular product

The therapeutic effect of fibroblast-like cells obtained from the stromal vascular fraction of subcutaneous adipose tissue of mice and cultured for the treatment of bone marrow form of acute radiation syndrome was studied on a mouse experimental model. The cells were identified as multipotent mesenchymal stem (stromal) cells, owing to adhesion to plastic, confluent monolayer formation during cultivation, and the fact that osteogenic differentiation in vitro resulted in osteoblast maturation and calcium deposit formation, which indicated their multipotent nature. Irradiation of laboratory rodents was conducted using theX-ray therapy unit “RUM-17”. Stromal cells were obtained from subcutaneous adipose tissue of a mouse and grown in a culture of 3–4 passages and used as a cell product. Cell transplantation was performed 24 h after uniformX-ray irradiation of mice at a dose of 7.8 Gy. This is the first study to compare the therapeutic efficacy of allogeneic transplantation of multipotent mesenchymal stem cells with the different routes (intravenous and intraperitoneal) of cell suspension administration. A significant increase was found in the survival rate of mice during the 30-day follow-up period after lethal dose irradiation, which depended on the number of injected cells and delivery method of the biomedical cell product. Thus, with intravenous administration of 30 and 60 × 103multipotent mesenchymal stem cells, the 30-day survival rate of mice after irradiation at a dose of 7.8 Gy increased by 54.5% and 40%, respectively, compared with that of untreated animals (p= 0.03). An increase in the number of cells in the cell product to 120 × 103/mouse led to a decrease in therapy effectiveness. In intraperitoneal administration, the protection of animals from death was 57% after transplantation of 30 and 60 × 103cells (p= 0.039) and 50% after application of 120 × 103cells. On day 30 after irradiation, in the introduction of a cellular product in different schemes, 70%–80% of animals showed restoration of the values of the main indicators of the hematopoiesis system to initial levels. Thus, cell therapy using multipotent mesenchymal stem cells isolated from adipose tissue with intravenous and intraperitoneal delivery routes of the cellular product to the irradiated body protects mice from death after exposure toX-ray radiation in lethal doses, decreasing the severity of radiation damage to the hematopoietic system in mice, and provides prospects for further research as an effective and safe treatment for acute radiation sickness.

Synthesis and Characterization of Low Molecular Weight Irradiated Chitosan in Various Water Levels and Gamma-Ray Doses

Chitosan is a biopolymer derived from marine animal shell waste that exhibits numerous pharmacological activities. However, its high molecular weight limits the application in various fields due to its low solubility. Therefore, this study aims to synthesize low molecular weight chitosan using varying water content and doses of gamma irradiation. To initiate chitosan degradation, H2O (5 and 10 mL) was added, followed by gamma ray irradiation at doses of 5 and 10 kGy. The Molecular Weight (MW) of degraded chitosan was determined using Gel Permeation Chromatography (GPC), while Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize the functional groups and degree of deacetylation of chitosan. The study found that the molecular weight of irradiated chitosan decreased as the irradiation dose and H2O addition increased. The addition of 10 mL of water and gamma irradiation at a dose of 10 kGy has been found to reduce the molecular weight of chitosan to 118 kDa, with a high deacetylation degree of 86.78%. The FTIR analysis showed no significant changes in the functional groups, indicating that gamma irradiation did not affect the structure of chitosan.

Protective effects of tauroursodeoxycholate against radiation-induced intestinal injury in a mouse model

In patients with high-level radiation exposure, gastrointestinal injury is the main cause of death. Despite the severity of damage to the gastrointestinal tract, no specific therapeutic option is available. Tauroursodeoxycholic acid (TUDCA) is a conjugated form of ursodeoxycholic acid that suppresses endoplasmic reticulum (ER) stress and regulates various cell-signaling pathways. We investigated the effect of TUDCA premedication in alleviating intestinal damage and enhancing the survival of C57BL/6 mice administered a lethal dose (15Gy) of focal abdominal irradiation. TUDCA was administered to mice 1 h before radiation exposure, and reduced apoptosis of the jejunal crypts 12 h after irradiation. At later timepoint (3.5 days), irradiated mice manifested intestinal morphological changes that were detected via histological examination. TUDCA decreased the inflammatory cytokine levels and attenuated the decrease in serum citrulline levels after radiation exposure. Although radiation induced ER stress, TUDCA pretreatment decreased ER stress in the irradiated intestinal cells. The effect of TUDCA indicates the possibility of radiation therapy for cancer in tumor cells. TUDCA did not affect cell proliferation and apoptosis in the intestinal epithelium. TUDCA decreased the invasive ability of the CT26 metastatic colon cancer cell line. Reduced invasion after TUDCA treatment was associated with decreased matrix metalloproteinase (MMP)-7 and MMP-13 expression, which play important roles in invasion and metastasis. This study shows a potential role of TUDCA in protecting against radiation-induced intestinal damage and inhibiting tumor cell migration without any radiation and radiation therapy effect.

Radiation-Induced DNA Damage in Uveal Melanoma Is Influenced by Dose Delivery and Chromosome 3 Status.

The purpose of this study was to analyze the extent of DNA breaks in primary uveal melanoma (UM) with regard to radiotherapy dose delivery (single-dose versus fractionated) and monosomy 3 status. A total of 54 patients with UM were included. Stereotactic radiotherapy (SRT) was performed in 23 patients, with 8 undergoing single-dose SRT (sdSRT) treatment and 15 receiving fractionated SRT (fSRT). DNA breaks in the enucleated or endoresected tumors were visualized by a TUNEL assay and quantified by measuring the TUNEL-positive area. Protein expression was analyzed by immunohistochemistry. Co-detection of chromosome 3 with proteins was performed by immuno-fluorescent in situ hybridization. The amount of DNA breaks in the total irradiated group was increased by 2.7-fold (P < 0.001) compared to non-irradiated tissue. Tumors treated with fSRT were affected more severely, showing 2.1-fold more DNA damage (P = 0.007) compared to the cases after single (high) dose irradiation (sdSRT). Monosomy 3 tumors showed less DNA breaks compared to disomy 3 samples (P = 0.004). The presence of metastases after radiotherapy correlated with monosomy 3 and less DNA breaks compared to patients with non-metastatic cancer in the combined group with fSRT and sdSRT (P < 0.05). Fractionated irradiation led to more DNA damage than single-dose treatment in primary UM. As tumors with monosomy 3 showed less DNA breaks than those with disomy 3, this may indicate that they are less radiosensitive, which may influence the efficacy of irradiation.

Single atoms and metal nanoclusters anchored to graphene vacancies

Fabricating dispersed single atoms and size-controlled metal nanoclusters remains a difficult challenge due to sintering. Here, we demonstrate that atoms and clusters can be immobilized using atomically clean defect-engineered graphene as the matrix. The graphene is first cleaned of surface contamination with laser heating, after which low-energy Ar irradiation is used to create spatially well-separated vacancies into it. Metal atoms are then evaporated either via thermal or ebeam evaporation onto graphene, where they diffuse until being trapped into a vacancy. The density of embedded structures can be controlled through irradiation dose, and the size of the structures through evaporation time. The resulting structures are confirmed through atomic-resolution scanning transmission electron microscopy and electron energy loss spectroscopy. We demonstrate here incorporation of Al, Ti, Fe, Ag and Au single atoms or nanoclusters, but the method should work equally well for other elements.

Reflected shear wave computed tomography for elasticity imaging of 3D cell cultures using a single-element transducer

Shear wave elasticity imaging (SWEI) has long been used to quantify tissue stiffness in clinical diagnoses. In comparison with conventional bulk-based measurement methods, SWEI offers the distinct advantage of nondestructive sampling, thereby enabling the spatiotemporal monitoring of stiffness variations. However, applying SWEI to assessing millimeter-scale three-dimensional (3D) cell environments has faced limitations despite its potential in mechanobiology, and the existing techniques are insufficient for imaging inhomogeneous media environments. In this study, we investigated a computed tomography technique specifically designed for reflected SWEI (called R-SWCT) by rotational scanning in a sample using a 20-MHz ultrasound single-element transducer. We focused on samples containing a single inclusion with higher stiffness than the surrounding medium, mimicking the situation of a tumor sphere embedded in a 3D gel. Our method reconstructs the stiffness distribution using a curve-fitting method, wherein coefficients of Gaussian curves are fitted to the wavefronts of simulated signals. This reconstruction method yielded coefficients that closely approximated the wavefronts obtained experimentally, with a maximum difference between the measured and predicted shear wave speeds of only 0.1 m/s for phantom samples and 0.2 m/s for cell samples. The system and methodologies proposed in this research have demonstrated the feasibility of employing R-SWCT to study the remodeling dynamics of a cell group within its surrounding matrix in an in vitro setting. This noninvasive method also facilitates an exploration of how irradiation dosage used in radiation therapy can induce temporal alterations in the shear wave speed in 3D cancer cell cultures.

Effect of Gamma Irradiation Dose on the Interface and Tribological Properties of Acrylonitrile–Butadiene–Styrene

Effect of Gamma Irradiation Dose on the Interface and Tribological Properties of Acrylonitrile–Butadiene–Styrene

Chloroquine degradation in aqueous solution under electron beam irradiation

Abstract Pharmaceutically active compounds are the most widely produced and consumed consumer products that pose a substantial threat to the environment and living organisms owing to their pharmacokinetics, side effects, and contraindications. In this study, the degradation of chloroquine (CQ), a popular antimalarial and recently proposed COVID-19 drug, was investigated under electron beam (EB) irradiation of aqueous solutions. Both the hydroxyl radical and hydrated electron generated in the radiolysis of water contribute to the degradation of CQ in aqueous solution. The overall removal efficiency for 125 mg·L-1 of the CQ solution under EB treatment is reported to be &gt;80% at neutral pH at a maximum irradiation dose of 7 kGy. Removal efficiency is further favored by acidic and slightly alkaline conditions where reactions with hydroxyl radicals and hydrated electrons are favored, respectively. Additionally, increments in the applied dose resulted in the increased removal efficiency for the same concentration of CQ. Conversely, the removal efficiency decreased with increasing concentration of CQ at the same irradiation dose. The initial solution pH, applied irradiation dose, and initial pollutant concentration play an important role in the EB-induced degradation of CQ by influencing the available oxidizing and reducing species. The chemical oxygen demand (COD) and total organic carbon (TOC) were not significantly decreased during the treatment process and indicated the formation of organic byproducts, which were not further degraded under the current experimental conditions.