Journal Description

Radiation

Radiation is an international, peer-reviewed, open access journal on scientific advances and applications of radiotherapy, immunotherapy, radiology and radiation technologies across multiple fields, published quarterly online by MDPI.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 24.5 days after submission; acceptance to publication is undertaken in 3.4 days (median values for papers published in this journal in the second half of 2023).
Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Radiation is a companion journal of Cancers.

Imprint Information Journal Flyer Open Access ISSN: 2673-592X

Latest Articles

10 pages, 1544 KiB

Open AccessArticle

Metastasis-Directed Stereotactic Body Radiotherapy in Prostate Cancer Patients Treated with Systemic Therapy and Undergoing Oligoprogression: Report on 11 Consecutive Cases

by Emanuele Chioccola, Mara Caroprese, Christina A. Goodyear, Angela Barillaro, Caterina Oliviero, Stefania Clemente, Chiara Feoli, Luigi Formisano, Antonio Farella, Laura Cella, Manuel Conson and Roberto Pacelli

Radiation 2024, 4(2), 115-124; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4020009 - 12 Apr 2024

Abstract

Background: Stereotactic body radiotherapy (SBRT) targeted at metastatic sites of disease progression is emerging as a potential therapeutic approach for managing oligoprogressive prostate cancer. However, a definitive benefit has yet to be demonstrated. Herein, we present our institution’s experience with this treatment approach. Methods: From April 2018 to March 2023, 11 patients affected by oligoprogressive prostate cancer were treated with SBRT targeting the nodal or bone sites of progression while maintaining the ongoing systemic therapy. Three patients were undergoing single-agent ADT (Androgen Deprivation Therapy), while the remaining eight were receiving a subsequent line of systemic therapy. All patients were evaluated with a pre-treatment 68Ga-PSMA-11 or 18F-fluorocholine PET/CT, which demonstrated between one and five localizations of disease. All the active sites were treated with SBRT in one (15–24 Gy) or three (21–27 Gy) fractions, except for one patient, who was treated in five fractions (35 Gy). PSA serum levels were tested at baseline, one month after RT and at least every three months; all patients underwent a post-treatment 68Ga-PSMA-11 or 18F-fluorocholine PET/CT. The evaluated endpoints were PSA response, defined as a post-treatment decrease >50% from baseline measured within 6 months, time to next-line systemic treatment (NEST), local control (LC), biochemical progression-free survival (bPFS), radiological progression-free survival (rPFS) and freedom from polymetastatic progression (FPP). Results: Nineteen lesions were treated (seven nodal and twelve bone). At a median follow-up of 19 months (7–63), 9 of the 11 patients had a PSA response; all patients had local control of the treated metastases. A total of six patients switched to a next-line systemic treatment, with a median NEST of 13 months. Six patients had polymetastatic progression with an FPP median time of 19 months. No patients died during the follow-up period. The SBRT-related toxicity was negligible. Conclusions: Our data support the use of SBRT targeting the sites of oligoprogressive disease before moving to a subsequent line of systemic treatment in patients with metastatic prostate cancer. Prospective studies to evaluate the potential impact of this approach on overall survival are warranted. Full article

(This article belongs to the Topic Innovative Radiation Therapies)

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14 pages, 1550 KiB

Open AccessReview

Cultivation of Vitamin C-Rich Vegetables for Space-Radiation Mitigation

by Alireza Mortazavi, Helia Yarbaksh, Batool Faegheh Bahaaddini Baigy Zarandi, Reza Yarbakhsh, Fatemeh Ghadimi-Moghaddam, Syed Mohammad Javad Mortazavi, Masoud Haghani, Donya Firoozi and Lembit Sihver

Radiation 2024, 4(1), 101-114; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010008 - 08 Mar 2024

Abstract

Space exploration introduces astronauts to challenges, such as space radiation and microgravity. Researchers have investigated vitamin C as a potential radiation mitigator, as well as antioxidants for sustaining astronaut health. Our own studies demonstrate vitamin C’s life-saving radioprotective effects and its potential as a radiation mitigator, thus highlighting promise, even when administered 24 h post-exposure. This is particularly relevant in scenarios where astronauts may be exposed to sudden large solar particle events, potentially resulting in lethal doses of space radiation. The success of vegetable cultivation on the International Space Station using NASA’s Veggie system offers fresh, vitamin C-rich food. While approved supplements address somatic function, further research is needed to optimize vitamin C’s efficacy in humans, and to develop appropriate antioxidant cocktails for space missions. The variable vitamin C content in vegetables underscores the necessity for the utilization of artificial intelligence (AI) to assist astronauts in selecting and cultivating the vitamin C-rich vegetables best-suited to combat high levels of space radiation and microgravity. Particularly, AI algorithms can be utilized to analyze various factors, such as nutritional content, growth patterns, and cultivation methods. In conclusion, vitamin C shows significant potential for mitigating space radiation, and ongoing research aims to enhance astronaut health through optimal dietary strategies. Full article

(This article belongs to the Section Radiation and Its Application in Oncology and Radiation Protection)

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16 pages, 2571 KiB

Open AccessArticle

Assessing Radiation Effects on Chemo-Treated BT20 and 4T1 Breast Cancer, and Neuroblastoma Cell Lines: A Study of Single and Multiple-Cell Ionization via Infrared Laser Trapping

by Mulugeta S. Goangul, Daniel B. Erenso, Ying Gao, Li Chen, Kwame O. Eshun, Gisela Alvarez and Horace T. Crogman

Radiation 2024, 4(1), 85-100; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010007 - 07 Mar 2024

Abstract

Background: Our study aimed to assess the radiation sensitivity of BT20, a human breast tumor cell line, using the laser-trapping technique and compare it with N2a and 4T1 cells. Additionally, we investigated the impact of the antitumor compound 2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) on radiation sensitivity. Methods and Materials: We employed laser trapping to calculate both the threshold ionization energy (TIE) and threshold radiation dose (TRD) for BT20, N2a, and 4T1 cells. We assessed the effect of DMDD on BT20 cells’ radiosensitivity and conducted comparisons across these cell lines. Results: Our findings reveal that DMDD significantly enhances the radiosensitivity of BT20 breast carcinoma cells. Moreover, we observed distinct trends in TIE and TRD across the three cell lines, with differences attributed to variations in cell size and composition. When multiple cell ionizations were considered, a notable reduction in TRD was observed, implicating factors such as the chain effect of ionizing radiation and the influence of DMDD. The study found that TIE increased with the number of cells in the trap while TRD consistently decreased across all three cell lines, suggesting comparable radiation sensitivity, and oligostilbene treatment further reduced TRD, presenting the potential for enhancing therapeutic ratios in cancer treatment. Conclusion: The antitumor compound DMDD enhances the radiosensitivity of BT20 breast carcinoma cells, highlighting its potential in cancer treatment. Furthermore, our study underscores the impact of cell size and multiple-cell ionizations on TRD. Leveraging laser trapping techniques, biocompatible nanoparticles, and advanced optical tweezers opens promising avenues for personalized and effective cancer therapy approaches. Full article

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16 pages, 2630 KiB

Open AccessCommunication

Calculations of the Radiation Dose for the Maximum Hormesis Effect

by Katsuhito Kino

Radiation 2024, 4(1), 69-84; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010006 - 01 Mar 2024

Abstract

To date, the radiation-adaptive response has been reported as a low-dose-related phenomenon and has been associated with radiation hormesis. Well-known cancers are caused by non-radiation active reactants, in addition to radiation. A model of suppression for radiation-specific cancers was previously reported, but the model did not target radiation-nonspecific cancers. In this paper, we describe kinetic models of radiation-induced suppressors for general radiation non-specific cancers, estimating the dose M that induces the maximum hormesis effect while satisfying the condition that the risk is approximately proportional to a dose above NOAEL (No Observed Adverse Effect Level). The radiation hormesis effect is maximal when the rate constant for generation of a risk-reducing factor is the same as the rate constant for its decomposition. When the two rate constants are different, the dose M at which the radiation hormesis effect is maximized depends on both rate constants, but the dose M increases as the two rate constants approach each other, reaching a maximum dose. The theory proposed in this paper can only explain existing experiments with extremely short error bar lengths. This theory may lead to the discovery of unknown risk-reducing factor at low doses and the development of risk-reducing methods in the future. Full article

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19 pages, 4232 KiB

Open AccessArticle

Deep Texture Analysis—Enhancing CT Radiomics Features for Prediction of Head and Neck Cancer Treatment Outcomes: A Machine Learning Approach

by Aryan Safakish, Lakshmanan Sannachi, Amir Moslemi, Ana Pejović-Milić and Gregory J. Czarnota

Radiation 2024, 4(1), 50-68; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010005 - 28 Feb 2024

Abstract

(1) Background: Some cancer patients do not experience tumour shrinkage but are still at risk of experiencing unwanted treatment side effects. Radiomics refers to mining biomedical images to quantify textural characterization. When radiomics features are labelled with treatment response, retrospectively, they can train predictive machine learning (ML) models. (2) Methods: Radiomics features were determined from lymph node (LN) segmentations from treatment-planning CT scans of head and neck (H&N) cancer patients. Binary treatment outcomes (complete response versus partial or no response) and radiomics features for n = 71 patients were used to train support vector machine (SVM) and k-nearest neighbour (k-NN) classifier models with 1–7 features. A deep texture analysis (DTA) methodology was proposed and evaluated for second- and third-layer radiomics features, and models were evaluated based on common metrics (sensitivity (%S_n), specificity (%S_p), accuracy (%Acc), precision (%Prec), and balanced accuracy (%Bal Acc)). (3) Results: Models created with both classifiers were found to be able to predict treatment response, and the results suggest that the inclusion of deeper layer features enhanced model performance. The best model was a seven-feature multivariable k-NN model trained using features from three layers deep of texture features with %S_n = 74%, %S_p = 68%, %Acc = 72%, %Prec = 81%, %Bal Acc = 71% and with an area under the curve (AUC) the receiver operating characteristic (ROC) of 0.700. (4) Conclusions: H&N Cancer patient treatment-planning CT scans and LN segmentations contain phenotypic information regarding treatment response, and the proposed DTA methodology can improve model performance by enhancing feature sets and is worth consideration in future radiomics studies. Full article

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13 pages, 3528 KiB

Open AccessArticle

Proton- and Neutron-Induced SEU Cross-Section Modeling and Simulation: A Unified Analytical Approach

by Gennady I. Zebrev, Nikolay N. Samotaev, Rustem G. Useinov, Artur M. Galimov, Vladimir V. Emeliyanov, Artyom A. Sharapov, Dmitri A. Kazyakin and Alexander S. Rodin

Radiation 2024, 4(1), 37-49; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010004 - 14 Feb 2024

Abstract

A new physics-based compact model, which makes it possible to simulate in a unified way the neutrons and protons of cosmic ray-induced SEU cross-sections, including the effects from nuclear reaction products and from direct ionization by low-energy protons, has been proposed and validated. The proposed approach is analytical and based on explicit analytical relationships and approximations with physics-based fitting parameters. GEANT4 or SRIM numerical calculations can be used as an aid to adjust or refine the phenomenological parameters or functions included in the model, taking into account real geometrical configurations and chemical compositions of the devices. In particular, explicit energy dependencies of the soft error cross-sections for protons and neutrons over a wide range of nucleon energies were obtained and validated. The main application areas of the developed model include space physics, accelerator studies high energy physics and nuclear experiments. Full article

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11 pages, 637 KiB

Open AccessCommunication

Characterizing the Early Acidic Response in Advanced Small Modular Reactors Cooled with High-Temperature, High-Pressure Water

by Abida Sultana, Jintana Meesungnoen and Jean-Paul Jay-Gerin

Radiation 2024, 4(1), 26-36; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010003 - 09 Feb 2024

Abstract

Utilizing Monte Carlo multi-track chemistry simulations along with a cylindrical instantaneous pulse (Dirac) irradiation model, we assessed the initial acidic response in both subcritical and supercritical water under high radiation dose rates. This investigation spans a temperature range of 300 to 500 °C at a nominal pressure of 25 MPa, aligning with the operational conditions anticipated in proposed supercritical water (SCW)-cooled small modular reactors (SCW-SMRs). A pivotal finding from our study is the observation of a significant ‘acid spike’ effect, which shows a notable intensification in response to increasing radiation dose rates. Our results bring to light the potential risks posed by this acidity, which could potentially foster a corrosive environment and thereby increase the risk of accelerated material degradation in reactor components. Full article

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9 pages, 3030 KiB

Open AccessArticle

Acquisition Conditions for Lu-177 DOTATATE Imaging

by Yuri Sagisaka, Yasuyuki Takahashi, Shota Hosokawa, Niina Kanazawa, Hiroki Yamamoto, Go Takai and Keiji Nagano

Radiation 2024, 4(1), 17-25; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010002 - 19 Jan 2024

Abstract

We investigated imaging conditions for the distribution of lutetium oxodotreotide (Lu-177 DOTATATE) in the body during peptide receptor radionuclide therapy for neuroendocrine tumor (NET). We investigated imaging conditions using gamma rays emitted from the radionuclide. The gamma rays had energy peaks at 113 and 208 keV and characteristic X-rays at 56 keV. Image quality was compared by utilizing a combination of low–medium-energy general-purpose (LMEGP) and medium-energy general-purpose (MEGP) collimators. This study included the measurement of total spatial resolution (Full Width at Half Maximum) using a line source phantom. We compared the image quality of static images using a plane phantom and SPECT images using a cylindrical phantom. This comparison involved assessing recovery coefficient curves, count ratio, and %CV. Imaging evaluation was also performed on one NET patient. In phantom studies and the clinical study, comparing the combination of the three energy peaks (56 + 113 + 208 keV) using the LMEGP collimator and the conventional combination (113 + 208 keV) using the MEGP collimator revealed a count ratio of 1.9 times the maximum, stable %CV, and the best image quality. Full article

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16 pages, 2672 KiB

Open AccessReview

Potential Effects of Anthropogenic Radiofrequency Radiation on Cetaceans

by Alfonso Balmori-de la Puente and Alfonso Balmori

Radiation 2024, 4(1), 1-16; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation4010001 - 30 Dec 2023

Abstract

Cetaceans are cast to shore for a large number of reasons, although sometimes it is not clear why. This paper reviews the types and causes of cetacean strandings, focusing on mass strandings that lack a direct scientific explanation. Failure of cetacean orientation due to radiofrequency radiation and alterations in the Earth’s magnetic field produced during solar storms stand out among the proposed causes. This paper proposes the possibility that anthropogenic radiofrequency radiation from military and meteorological radars may also cause these strandings in areas where powerful radars exist. A search of accessible databases of military and meteorological radars in the world was carried out. Research articles on mass live strandings of cetaceans were reviewed to find temporal or spatial patterns in the stranding concentrations along the coast. The data showed certain patterns of spatial and temporal evidence in the stranding concentrations along the coast after radar setup and provided a detailed description of how radars may interfere with cetacean echolocation from a physiological standpoint. Plausible mechanisms, such as interference with echolocation systems or pulse communication systems, are proposed. This work is theoretical, but it leads to a hypothesis that could be empirically tested. Further in-depth studies should be carried out to confirm or reject the proposed hypothesis. Full article

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15 pages, 4548 KiB

Open AccessArticle

Laminated Flow-Cell Detector with Granulated Scintillator for the Detection of Tritiated Water

by Nile E. J. Dixon, Stephen D. Monk, James Graham and David Cheneler

Radiation 2023, 3(4), 211-225; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3040017 - 03 Nov 2023

Abstract

Nuclear sites require regular measurements of the air, soil, and groundwater to ensure the safety of the surrounding environment from potentially hazardous levels of contamination. Although high-energy beta and gamma emitters can often be detected instantly using fixed dosimeters, the detection of low-energy beta emitters is a difficult challenge, especially in groundwater, as its radiation is easily self-absorbed by the surrounding medium. Therefore, it is common practice to sample groundwater and transfer it to a laboratory for analysis using Liquid Scintillation Counting. This work demonstrates a new detector design for the real-time monitoring of tritiated water, a weak beta emitter. This design utilizes a flow cell filled with a granulated scintillator to maximize the surface area of the sample. The cavity is made from plastic sheets, which allow rapid manufacture using readily available lamination sheets. A column of SiPMs in coincidence counting mode has been implemented to reduce noise and allow future extensions to the flow cell for greater detection rates while allowing the detector to fit within limited spaces such as groundwater monitoring boreholes. Using multiple concentrations of tritiated water, this detector has been validated and calibrated, obtaining a minimum detection activity of 26.356 ± 0.889 Bq/mL for a 1-day counting period. Full article

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8 pages, 8375 KiB

Open AccessCase Report

Chernobyl’s Aftermath: Multiple Manifestations of Basalioma in a Patient after Radioactive Contamination in 1986

by Marcel Ebeling, Konrad Steinestel, Michael Grunert, Alexander Schramm, Frank Wilde, Sebastian Pietzka and Andreas Sakkas

Radiation 2023, 3(4), 203-210; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3040016 - 24 Oct 2023

Abstract

Background: The Chernobyl nuclear disaster is still considered the worst nuclear accident in history. The particles were dispersed over the former USSR and large parts of Western Europe, leading to radioactive exposure to more than 10 million people. Radioactivity is a risk factor for the development of basal cell carcinoma (BCC), since radiation-induced mutations in both Sonic hedgehog (Shh) signaling pathway genes and TP53 have been described. Methods: We present the case of a patient with a history of radiation exposure following the 1986 Chernobyl accident who presented to our outpatient clinic with recurrent basal cell carcinoma in the facial region. Case: The patient presented to our clinic with two facial lesions suspicious for BCC. Although there were no typical risk factors, 11 BCCs had previously been removed. The patient had been building shelters for the construction workers working on the sarcophagus around the destroyed reactor immediately after the 1986 accident. Staging using an 18F-FDG-PET/CT as well as ultrasound of the abdomen revealed no other tumor manifestations. Diagnostic excision of the two facial lesions was performed, and a histopathological workup revealed BCC at the right temporal region and acanthopapillomatosis with no sign of malignancy at the corner of the mouth. After presentation to the tumor board, complete resection of the BCC was initiated. Conclusions: This case demonstrates the value of early use of 18F-FDG-PET/CT in staging/restaging to visualize BCC location, local spread and potential metastases or secondary tumors and to aid in the decision for therapeutic management. Full article

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20 pages, 3270 KiB

Open AccessArticle

Modulating Synchrotron Microbeam Radiation Therapy Doses for Preclinical Brain Cancer

by Elette Engels, Jason R. Paino, Sarah E. Vogel, Michael Valceski, Abass Khochaiche, Nan Li, Jeremy A. Davis, Alice O’Keefe, Andrew Dipuglia, Matthew Cameron, Micah Barnes, Andrew W. Stevenson, Anatoly Rosenfeld, Michael Lerch, Stéphanie Corde and Moeava Tehei

Radiation 2023, 3(4), 183-202; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3040015 - 14 Oct 2023

Abstract

Synchrotron Microbeam Radiation Therapy (MRT) is an innovative technique that spatially segments the synchrotron radiation field for cancer treatment. A microbeam peak dose is often hundreds of times the dose in the valley (the sub-millimeter region between the peaks of the microbeams). Peak and valley doses vary with increasing depth in tissue which effects tumor dose coverage. It remains to be seen whether the peak or valley is the primary factor in MRT cancer control. This study investigates how unilateral MRT doses can be modulated using a bolus, and identifies the valley dose as a primary factor in MRT cancer control. Fischer rats bearing 9 L gliosarcoma tumors were irradiated with MRT at the Imaging and Medical Beam Line of the Australian Synchrotron. MRT valley doses of 8–15 Gy (250–1040 Gy peak doses) were used to treat tumors with and without a 5 mm dose-modulating bolus. Long-term survival depended on the valley dose primarily (92% correlation), and the use of the bolus reduced the variance in animal survival and improved to the mean survival of rats treated with MRT by 47% and 18% using 15 Gy and 8 Gy valley doses, respectively. Full article

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18 pages, 2387 KiB

Open AccessArticle

Early and Transient Formation of Highly Acidic pH Spikes in Water Radiolysis under the Combined Effect of High Dose Rate and High Linear Energy Transfer

by Md Ibrahim Bepari, Jintana Meesungnoen and Jean-Paul Jay-Gerin

Radiation 2023, 3(3), 165-182; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3030014 - 11 Sep 2023

Abstract

(1) Background: Water radiolysis leads to the formation of hydronium ions H₃O⁺ in less than 50 fs, resulting in the formation of transient acidic pH spikes in the irradiated water. The purpose of this study is to examine the time evolution of these spikes of acidity under irradiation conditions combining both high absorbed dose rate and high-LET radiation. (2) Methods: The early space–time history of the distributions of the various reactive species was obtained using our Monte Carlo multitrack chemistry simulation code IONLYS-IRT. To simulate different LETs, we used incident protons of varying energies as radiation sources. The “instantaneous pulse” (or Dirac) model was used to investigate the effect of dose rate. (3) Results: One major finding is that the combination of high dose rates and high LETs is clearly additive, with a very significant impact on the pH of the solution. For example, at 1 ns and for a dose rate of ~10⁷ Gy/s, the pH drops from ~4.7 to 2.7 as the LET increases from ~0.3 to 60 keV/μm. (4) Conclusions: Confirming previous work, this purely radiation chemical study raises the question of the possible importance and role of these spikes of acidity in underpinning the physical chemistry and biology of the “FLASH effect”. Full article

(This article belongs to the Topic Innovative Radiation Therapies)

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12 pages, 2568 KiB

Open AccessArticle

In Vitro Radioenhancement Using Ultrasound-Stimulated Microbubbles: A Comparison of Suspension and Adherent Cell States

by Giulia McCorkell, Masao Nakayama, Bryce Feltis, Terrence J. Piva and Moshi Geso

Radiation 2023, 3(3), 153-164; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3030013 - 10 Aug 2023

Abstract

Background: Ultrasound-stimulated microbubbles (USMB) have shown potential for enhancing radiation treatment via cavitation and sonoporation mechanisms. However, in vitro studies have produced inconsistent results, with adherent cells demonstrating no radioenhancement. This study aims to investigate the effect of cell adherence on in vitro radioenhancement using USMB and radiation. Method: Lung metastases of follicular thyroid carcinoma cells (FTC-238) and non-small cell lung carcinoma cells (NCI-H727) were treated, both when adhered and in suspension, using 1.6% (v/v) Definity™ microbubbles, ~90 s of 2 MHz ultrasound with mechanical index 0.9, and either 3 Gy or 6 Gy of megavoltage (MV) X-rays. The cell viability was measured using an MTS assay 72 h post-treatment, and statistical analysis was conducted using a three-way analysis of variance. Results: Statistically significant differences were observed for cells treated when adherent compared to suspended. An additive effect was detected in NCI-H727 cells treated in suspension, but not while adherent, while no enhancement was observed for FTC-238 cells in either culture state. Conclusions: To the best of our knowledge, this is the first study to directly compare the effect of cell adherence on the radioenhancement potential of USMB in vitro, and the first to do so using a metastatic cell line. Full article

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15 pages, 2547 KiB

Open AccessArticle

An Advanced Optimization Method to Minimize the Detection Limit of Liquid Scintillation Counter to Measure Low-Level Tritium Activity in Groundwater

by Al Mamun

Radiation 2023, 3(3), 138-152; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3030012 - 26 Jul 2023

Cited by 1

Abstract

In arid regions, the tritium concentration in groundwater is typically very low and often falls below the minimum detectable activity (MDA) of the conventional liquid scintillation counter (LSC). Therefore, to measure the tritium activity concentration, it is necessary to lower the detection limit so that the scintillation counter can detect it. In the present study, several methods are discussed which are effective at lowering the detectable activity of tritium. One of these methods is to enrich the tritium activity concentration by ten- to fortyfold of the initial concentration of the tritium. Twelve spiked samples with known amounts of tritium, five with high concentrations and seven with low concentrations, were enriched by the electrolysis process. The results indicated that enriching the tritium levels in groundwater lowers the MDA value. Other methods are minimizing background radiation using low-background materials for sample containers, increasing the measurement efficiency of the scintillation counter and counting time, and shielding the sample from environmental radiation using the shutter option in LSC. Moreover, reducing the number of interfering contaminants in the sample can lower the uncertainty in measuring the tritium concentration in the water sample, which is beneficial for detecting low-level tritium in water to ensure public health and safety. Full article

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15 pages, 5203 KiB

Open AccessArticle

DoseMRT: A Software Package for Individualised Monte Carlo Dose Calculations of Synchrotron-Generated Microbeam Radiation Therapy

by Jason Paino, Matthew Cameron, Matthew Large, Micah Barnes, Elette Engels, Sarah Vogel, Moeava Tehei, Stéphanie Corde, Susanna Guatelli, Anatoly Rosenfeld and Michael Lerch

Radiation 2023, 3(2), 123-137; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3020011 - 20 Jun 2023

Cited by 1

Abstract

This work describes the creation and experimental validation of

D o s e M R T

, a new software package, and its associated workflow for dose calculations in synchrotron-generated broad beam and microbeam radiation treatment fields. The [...] Read more.

This work describes the creation and experimental validation of

D o s e M R T

, a new software package, and its associated workflow for dose calculations in synchrotron-generated broad beam and microbeam radiation treatment fields. The

D o s e M R T

software package allows users to import CT DICOM datasets into Geant4 for Monte Carlo dose calculations. It also provides basic treatment planning capabilities, simplifying the complexity of performing Geant4 simulations and making our Monte Carlo dose calculation algorithm accessible to a broader range of users. To demonstrate the new package, dose calculations are validated against experimental measurements performed in homogeneous water tank phantoms and the anatomically complex Alderson Radiotherapy Phantom for both broad-beam and microbeam configurations. Additionally,

D o s e M R T

is successfully utilised as the primary method for patient-specific treatment prescription in an in vivo experiment involving tumour-bearing rats at the Imaging and Medical Beamline of the Australian Synchrotron. Full article

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13 pages, 4860 KiB

Open AccessArticle

Impact of Temperature on Neutron Irradiation Failure-in-Time of Silicon and Silicon Carbide Power MOSFETs

by Fabio Principato, Carlo Cazzaniga, Maria Kastriotou, Christopher Frost, Leonardo Abbene and Francesco Pintacuda

Radiation 2023, 3(2), 110-122; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3020010 - 30 May 2023

Cited by 1

Abstract

Accelerated neutron tests on silicon (Si) and silicon carbide (SiC) power MOSFETs at different temperatures and drain bias voltages were performed at the ChipIr facility (Didcot, UK). A super-junction silicon MOSFET and planar SiC MOSFETs with different technologies made by STMicroelectronics were used. Different test methods were employed to investigate the effects of temperature on neutron susceptibility in power MOSFETs. The destructive tests showed that all investigated devices failed via a single-event burnout (SEB) mechanism. Non-destructive tests conducted by using the power MOSFET as a neutron detector allowed measuring the temperature trend of the deposited charge due to neutron interactions. The results of the destructive tests, in the −50 °C–180 °C temperature range, revealed the lack of a common trend concerning the FIT temperature dependence among the investigated SiC power MOSFETs. Moreover, for some test vehicles, the FIT-temperature curves were dependent on the bias condition. The temperature dependence of the FIT values, observed in some SiC devices, is weaker with respect to that measured in the Si MOSFET. The results of the non-destructive tests showed a good correlation between the temperature trends of the deposited charge with those of FIT data, for both Si and SiC devices. Full article

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12 pages, 808 KiB

Open AccessSystematic Review

Stereotactic Radiotherapy for Critically Located Pancreatic and Biliary Targets: A Review on Simultaneous Integrated Protection and Other Dose-Painting Strategies to Minimize Dose to Critical Organs at Risk

by Marco Lorenzo Bonù, Gloria Pedersoli, Jacopo Balduzzi, Mariateresa Cefaratti, Eneida Mataj, Gianluca Cossali, Lorenzo Granello, Navdeep Singh, Vittorio Morelli, Davide Tomasini, Francesco Frassine, Paola Vitali, Fabrizia Terraneo, Luca Triggiani, Michela Buglione and Stefano Maria Magrini

Radiation 2023, 3(2), 98-109; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3020009 - 16 May 2023

Cited by 1

Abstract

Background: Stereotactic Radiotherapy (SRT) in pancreatic and biliary tract cancer (PBC) suffers from proximity to any organ(s) at risk (OARs). Some strategies to manage this issue have previously been proposed, such as Simultaneous Integrated Protection (SIP), with the aim of maintaining a biological effective dose prescription while reducing toxicities. We performed a systematic review of the literature about SRT techniques applied in patients with tumor in proximity to OARs, with the aim of testing safety and efficacy. Methods: using PRISMA guidelines, we selected studies from a pool of more than 25,000 articles published from 2010 to 30 January 2023 that explored the use of SRT to deliver targeted treatment for PBC. We then selected the ones referring to decreases in prescription doses (for SRT only) in the area of overlap between planning target volume (PTV) and OARs. Local control (LC) and toxicities being detailed were exclusion criteria for articles. Results: 9 studies were included in our review, considering 368 patients. One-year LC probability ranges between 67% and 98.3% were reported. Late G3 toxicities ranged between 0% and 5.3%, while G4-G5 late toxicities were both reported as 0.3%. Conclusion: prioritizing critical OAR constraints limits severe toxicities while preserving LC in PBC SRT. Improving in-study reporting is essential to confirm these promising results. Full article

(This article belongs to the Topic Innovative Radiation Therapies)

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11 pages, 898 KiB

Open AccessArticle

Predicting Erectile Dysfunction after Highly Conformal, Hypofractionated Radiotherapy to the Prostate

by Kevin Martell, Conrad Bayley, Sarah Quirk, Jeremy Braun, Lingyue Sun, Wendy Smith, Harvey Quon and Kundan Thind

Radiation 2023, 3(2), 87-97; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3020008 - 02 May 2023

Cited by 1

Abstract

Background: Erectile dysfunction (ED) is common after prostate cancer treatment. It has been studied for conventional radiotherapy, but associations in the hypofractionated radiotherapy context are less clear. This study aimed to determine which factors are predicted for worsening ED after highly conformal, modestly hypofractionated radiotherapy to the prostate. Methods: Two hundred and twelve patients treated with 6000 cGy in twenty fractions across four centers were included in this study. Demographic, clinical, and dosimetry factors were then evaluated for post-treatment declines in erectile function using logistic regression and an explainable machine learning-based neural network. Results: 212 patients with a median follow-up of 3.6 years were evaluated. A total of 104 (49%) patients received androgen deprivation therapy. Prior to treatment, 52 (25%) patients were on ED medication. Mean doses to the penile bulb, penile crus, and penile shaft were 2490 (IQR: 1529–3656) cGy, 2095 (1306–3036) cGy, and 444 (313–650) cGy, respectively. Fifty-nine (28%) patients had a worsening of ED after treatment. On multivariable analysis, only the mean dose to the penile shaft [OR >345 vs. ≤345: 4.47 (1.43–13.99); p = 0.010] and pretreatment use of ED medication [OR yes vs. no: 12.5 (5.7–27.5; p < 0.001)] predicted for worsening ED. The neural network confirmed that the penile shaft mean dose and pre-treatment ED medication use are the most important factors in predicting ED. Conclusions: Pre-treatment ED and penile shaft dosimetry are important predictors for ED after hypofractionated radiotherapy for prostate cancer. Full article

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Open AccessArticle

How Safe Is Gadobutrol? Examining the Effect of Gadolinium Deposition on the Nervous System

by Maya Jammoul, Wassim Abou-Kheir and Nada Lawand

Radiation 2023, 3(2), 75-86; https://0-doi-org.brum.beds.ac.uk/10.3390/radiation3020007 - 03 Apr 2023

Abstract

This study aimed to evaluate the safety of gadobutrol, a gadolinium-based contrast agent used in medical imaging, by investigating its effect on the nervous system under physiological and inflammatory conditions. Male Sprague Dawley rats were divided randomly into four groups, including gadobutrol, saline, LPS + gadobutrol, and LPS + saline, and were given intraperitoneal injections of gadobutrol (2.5 mmol/kg) or saline for 20 days. Weekly sensorimotor and cognitive behavioral tests were performed over 4 weeks, and Gd concentration in nervous tissues was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Lactate dehydrogenase (LDH) activity was measured to evaluate cytotoxicity, and electromyography (EMG) recordings from the gastrocnemius muscle were also obtained to examine signal transmission in sciatic nerves. The results indicated that gadobutrol did not induce significant behavioral changes under normal conditions. However, when administered along with LPS, the combination led to behavioral dysfunction. ICP-MS analysis revealed a higher concentration of Gd in the cerebrum and spinal cord of gadobutrol + LPS-treated rats, while peripheral nerves showed lower concentrations. In addition, there was a significant increase in LDH activity in the hippocampus of the gadobutrol group. EMG responses to electrical stimulation of the sciatic nerve demonstrated a decreased threshold of nociceptive reflexes in the gadobutrol group. Overall, while gadobutrol may be considered safe under normal physiological conditions, the findings suggest that its safety may be compromised under inflammatory conditions. Full article

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