<abstract xml:lang="en"><title style='display:none'>Monte Carlo Calculations of Selected Dose Components in a Head Model for Boron Neutron Capture Therapy</title>Boron Neutron Capture Therapy is a very promising form of cancer therapy, consisting in irradiating a stable isotope of boron (10B) concentrated in tumor cells with a low energy neutron beam. This technique makes it possible to destroy tumor cells, leaving healthy tissues practically unaffected. In order to carry out the therapy in the proper way, the proper range of the neutron beam energy has to be chosen.In this paper we present the results of the calculations, using the MCNP code, aiming at studying the energetic dependence of the absorbed dose from the neutron capture reaction on boron (the therapeutic dose), and hydrogen and nitrogen (the injuring dose).</abstract>

Monte Carlo Calculations of Selected Dose Components in a Head Model for Boron Neutron Capture Therapy

<abstract xml:lang="en"><title style='display:none'>IEC/EN standards relating to diagnostic radiology equipment, and testing according to these standards</title>The paper gives an outlook of history, present and future of international (IEC) and European (EN) standards relating to diagnostic radiology equipment. These standards may be safety, quality assurance or performance standards; all of them include testing methods. Elaboration and publication of a new series of safety standards is in progress.Acceptance and conformance testing activity of the accredited Radiohygiene Department Laboratory of NRIRR according to these standards is reported.</abstract>

National Research Institute for Radiobiology and Radiohygiene (NRIRR), Budapest, Hungary

IEC & CENELEC TC62 Hungarian National Committee, Budapest, Hungary

IEC/EN standards relating to diagnostic radiology equipment, and testing according to these standards

<abstract xml:lang="en"><title style='display:none'>The design of an insulin pump - preliminary requirements (a technical note)</title>The material presented in this paper is an attempt to lay down requirements for the planned design of an insulin pump. An insulin pump is a device for continuous dosage of insulin at a selected rate, which facilitates treatment and improves the lives of diabetic patients. This paper is a compilation of medical requirements and user suggestions of presently offered insulin pumps.It seems important to establish proper requirements for a device before starting developing any design for an insulin pump.</abstract>

The design of an insulin pump - preliminary requirements (a technical note)

<abstract xml:lang="en"><title style='display:none'>Electron beam characteristics at extended source to surface distance for a Clinac-DHX linear accelerator</title>A uniform dose to the target site is required with a knowledge of delivered dose, central axis depth dose and beam flatness for successful electron treatment at an extended source to surface distance (SSD). In an extended SSD treatment under dosage of the lateral tissue may occur due to reduced beam flatness. To study the changes in beam characteristics, the depth dose curves, beam flatness and isodose distributions were measured at different SSDs from 100 to 120 cm for clinically used field sizes from (4×4) to (25×25) cm2 and beam energies ranging from 6 MeV to 20 MeV. Our results suggest that the change in depth dose is minimal except in the buildup region for most energy. In general surface dose is decreased as the SSD increased moderately. It was observed that the loss in beam flatness is significant for smaller fields, higher isodose lines, and lower energies. The penumbra enlarged and the uniformity index reduced with increasing SSD.</abstract>

Electron beam characteristics at extended source to surface distance for a Clinac-DHX linear accelerator

<abstract>
<title style='display:none'>Abstract</title>
<italic>Introduction:</italic> The purpose of this study was to determine the best normal tissue objective (NTO) values based on the dose distribution from brain tumor radiation therapy.
<italic>Material and methods:</italic> The NTO is a constraint provided by Eclipse to limit the dose to normal tissues by steepening the dose gradient. The multitude of NTO setting combinations necessitates optimal NTO settings. The Eclipse supports manual and automatic NTOs. Fifteen patients were re-planned using NTO priorities of 1, 50, 100, 150, 200, and 500 in combination with dose fall-offs of 0.05, 0.1, 0.2, 0.3, 0.5, 1 and 5 mm-1. NTO distance to planning target volume (PTV), start dose, and end dose were 1 mm, 105%, and 60%, respectively, for all plans. In addition, planning without the NTO was arranged to find out its effect on planning. The prescription dose covered 95% of the PTV. Planning was evaluated using several indices: conformity index (CI), homogeneity index (HI), gradient index (GI), modified gradient index (mGI), comprehensive quality index (CQI), and monitor unit (MU). Differences among automatic NTO, manual NTO, and without NTO were evaluated using the Wilcoxon signed-rank test.
<italic>Results:</italic> Comparisons obtained without and with manual NTO were: CI of 0.77 vs. 0.96 (p = 0.002), GI of 4.52 vs. 4.69 (p = 0.233), mGI of 4.93 vs. 3.95 (p = 0.001), HI of 1.10 vs. 1.10 (p = 0.330), and MU/cGy of 3.44 vs. 3.42 (p = 0.460). Planning without NTO produced a poor conformity index. Comparisons of automatic and manual NTOs were: CI of 0.92 vs. 0.96 (p = 0.035), GI of 5.25 vs. 4.69 (p = 0.253), mGI of 4.46 vs. 3.95 (p = 0.001), HI of 1.09 vs. 1.10 (p = 0.004), MU/cGy of 3.31 vs. 3.42 (p = 0.041).
<italic>Conclusions:</italic> Based on these results, manual NTO with a priority of 100 and dose fall-off 0.5 mm-1 was optimal, as indicated by the high dose reduction in normal tissue.
</abstract>

Normal tissue objective (NTO) tool in Eclipse treatment planning system for dose distribution optimization

<abstract xml:lang="en"><title style='display:none'>Estimating mental fatigue based on electroencephalogram and heart rate variability</title>The effects of long term mental arithmetic task on psychology are investigated by subjective self-reporting measures and action performance test. Based on electroencephalogram (EEG) and heart rate variability (HRV), the impacts of prolonged cognitive activity on central nervous system and autonomic nervous system are observed and analyzed. Wavelet packet parameters of EEG and power spectral indices of HRV are combined to estimate the change of mental fatigue. Then wavelet packet parameters of EEG which change significantly are extracted as the features of brain activity in different mental fatigue state, support vector machine (SVM) algorithm is applied to differentiate two mental fatigue states. The experimental results show that long term mental arithmetic task induces the mental fatigue. The wavelet packet parameters of EEG and power spectral indices of HRV are strongly correlated with mental fatigue. The predominant activity of autonomic nervous system of subjects turns to the sympathetic activity from parasympathetic activity after the task. Moreover, the slow waves of EEG increase, the fast waves of EEG and the degree of disorder of brain decrease compared with the pre-task. The SVM algorithm can effectively differentiate two mental fatigue states, which achieves the maximum classification accuracy (91%). The SVM algorithm could be a promising tool for the evaluation of mental fatigue.Fatigue, especially mental fatigue, is a common phenomenon in modern life, is a persistent occupational hazard for professional. Mental fatigue is usually accompanied with a sense of weariness, reduced alertness, and reduced mental performance, which would lead the accidents in life, decrease productivity in workplace and harm the health. Therefore, the evaluation of mental fatigue is important for the occupational risk protection, productivity, and occupational health.</abstract>

Estimating mental fatigue based on electroencephalogram and heart rate variability

<abstract>
<title style='display:none'>Abstract</title>
<italic>Introduction:</italic> Proton radiotherapy offers an advantage in sparing healthy tissue compared to photon therapy due to the specific interaction of protons with the patient’s body. In radiobiological experiments, alpha sources are commonly used instead of proton accelerators for convenience, but ensuring a uniform dose distribution is challenging. Properly designing the cell irradiation setup is crucial to reliably measure the average cellular response in such experiments. The objective of this research is to underscore the importance of dosimetric validation in radiobiological investigations. While Monte Carlo (MC) simulations offer valuable insights, their accuracy needs experimental confirmation. Once consistent results are obtained, the reliance on simulations becomes viable, as they are more efficient and less cumbersome compared to experimental procedures.
<italic>Material and methods:</italic> The simulations are performed with three MC code-based tools: Geant4-DNA, GATE, and SRIM to model the alpha radiation source and calculate dose distributions for various cell irradiation scenarios. Dosimetric verification of the experimental setup containing a 241Am source is performed using radiochromic films. Additionally, a clonogenic cell survival assay is carried out for the DU145 cell line.
<italic>Results:</italic> The study introduces a novel source simulation model derived from dosimetric measurements. The comparison between dosimetric results obtained with simulations and measured experimentally yields a gamma (3%/3mm) parameter value exceeding 99%. Furthermore, the LQ model parameters fitted to survival data of DU145 cells irradiated with particles emitted from 241Am source demonstrate consistency with previously published findings.
<italic>Conclusions:</italic> Radiobiological experiments investigate cellular responses to various irradiation scenarios. Challenges arise with densely ionizing radiation used in clinical practice, particularly in ensuring uniform dose delivery for reliable experiments. MC codes aid in simulating dose distribution and designing irradiation systems for consistent cell treatment. However, experimental validation is essential before relying on simulation results. Once confirmed, these results offer a cost-effective and time-efficient approach to planning radiobiological experiments compared to traditional laboratory work.
</abstract>

From radiobiology to radiotherapy: dose homogeneity in cells after alpha irradiation in measurements and Monte Carlo simulations

<abstract>
<title style='display:none'>Abstract</title>
The International Atomic Energy Agency (IAEA) has published the document namely “Guidelines on professional ethics for medical physicists” in 2023. This document complements several other IAEA publications on similar topics like IAEA Human Health Series 25. The “code of ethics” in medical physics practices is an essentially important topic and this publication covers the topic comprehensively. However, a few areas of improvement like the correlation of this publication with the concepts of leadership, safety culture, etc. have been identified in this review.
</abstract>

Book review: “Guidelines on professional ethics for medical physicists”, Training Course Series 78, Vienna, 2023

<abstract>
<title style='display:none'>Abstract</title>
<italic>Introduction:</italic> Bone regeneration materials are often used in dental surgery procedures. At present, we have the possibility to use materials from different groups due to the way they are obtained. The gold standard still remains the use of autogenous bone substitute material due to its osteogenic, osteoinductive and osteoconductive properties. The surgical removal of the third retained tooth is one of the most common procedures performed in dental surgery. As a result of such a procedure, bone tissue atrophy occurs. In order to avoid the formation of a bone defect on the distal surface of the second molar, an augmentation method using an autogenous dentin matrix can be used in such procedures.
<italic>Material and methods:</italic> Procedures for bilateral removal of retained third molars were performed in 15 patients. On one side, augmentation was performed with an autogenous dentin matrix obtained by grinding and preparing the extracted retained tooth (study group). On the opposite side, the bone defect was left to heal spontaneously (control group). After 6 months, the degree of bone regeneration was compared on the basis of bone density testing and the size of the resulting bone defect on the distal side was compared on the basis of radiographic examination.
<italic>Results:</italic> Analysis of the obtained material showed significant differences in healing after treatments with autogenous dentin matrix. Thus, the use of an autogenous dentin matrix made it possible to obtain a completely regenerated bone defect.
<italic>Conclusions:</italic> This procedure seems to be useful for bone regeneration after the removal of the third molar.
</abstract>

Radiological evaluation of mandibular alveolar reconstruction after retained third molar removal procedures using autogenous dentin matrix (ADM)

<abstract>
<title style='display:none'>Abstract</title>
The aim of this study was to present a novel framework for the analysis of the impact of murmurs on heart sounds recorded in real clinical environment. Heart sound records were rigorously selected from the PASCAL dataset using an automated signal quality assessment algorithm. Recordings from 159 patients were analyzed for spectral differences in normal, systolic and diastolic murmurs using a Multiple signal classification algorithm pseudo-spectrum. The spectral features evaluated for the first heart sound (S1) and the second heart sound (S2) were: energy, frequency and frequency density. Results show increased energy of fundamental heart sounds in systolic and diastolic murmurs similarly, whilst frequency is decreased inversely. Furthermore, the frequency density of the first and second heart sounds decreases in murmurs and it is shown to be the lowest in systolic murmur cases.
</abstract>

The study of the impact of murmurs on heart sounds by using multiple signal classification pseudo-spectrum

<abstract>
<title style='display:none'>Abstract</title>
<italic>Introduction:</italic> Squamous cell carcinoma of the head and neck region (HNSCC), with a positive status for high oncogenic potential human papillomavirus (HR-HPV), represents a clinically distinct disease entity compared to HPV-independent cases. Patients exhibit variations in prognosis and proposed therapy regimens. A prompt and reliable diagnosis of the presence of HPV infection could optimize the treatment for these patients. Currently employed treatment methods are long-term, expensive, and lack specificity, especially when administered separately.
<italic>Material and methods:</italic> The research objective of this study is to explore significant differences in the Raman spectra of biological samples taken from patients with HNSCC, facilitating the confirmation of HPV virus presence. Study groups were delineated based on histopathological diagnosis and molecular biology tests, confirming the biological activity of the virus and the presence of the HR-HPV form with a diagnosis of a specific subtype.
<italic>Results:</italic> To identify high oncogenic potential human papillomavirus (HR-HPV) infection as a crucial factor in squamous cell carcinoma of the head and neck region, an effective automatic data analysis system was established, relying on Raman microspectroscopy and multivariate analysis. Our results showed clear ranges of the Raman spectrum that differentiated between HPV-associated and non-HPV-associated cancers.
<italic>Conclusions:</italic> In conclusion, our experience shows a great diagnostic potential of Raman confocal microscopy with multidimensional statistical analysis. In the future, the use of this method may allow for the creation of an effective and automated HR-HPV detection system in neoplastic tissue.
</abstract>

Evaluation of changes caused by HR-HPV infection in squamous cell carcinoma of the head and neck using Raman microspectroscopy in combination with multivariate statistical analysis

<abstract>
<title style='display:none'>Abstract</title>
<italic>Introduction:</italic> Radiochromic film (RCF) is suitable for use as a dosimeter owing to its inherently superior spatial resolution and near-water equivalence. A new model of RCF recommended for measuring imaging dose in the kV nominal energy range was recently introduced onto the market. In this study, we investigate the dependence on the beam quality of GafChromic LD-V1 film’s radiation dose response.
<italic>Material and methods:</italic> Pieces of LD-V1 film were irradiated to air kerma ranging from 0 to 570 mGy in X-ray photons with beam qualities of 60 kV (HVL = 1.32 mm Al), 100 kV (HVL = 2.83 mm Al), 120 kV (HVL = 5.11 mm Al), 150 kV (HVL = 6.23 mm Al), and 180 kV (HVL = 0.54 mm Cu). The net reflectance from each film was obtained from a color flatbed scanner. For each beam quality, an analytical power function was fitted to the net reflectance - air kerma relationship and tested for differences.
<italic>Results:</italic> We have found that for the beam qualities investigated, the response of the Gafchromic LD-V1 film was not significantly dependent on energy, and a single calibration curve could be used. The total relative uncertainty and absolute error reached maxima of 18% and 80%, respectively for air kerma values less than 50 mGy, and remained below 10% for air kerma in the range 50 mGy to 570 mGy.
<italic>Conclusions:</italic> The results of our investigation revealed that the response of Gafchromic LD-V1 film is not significantly dependent on beam quality. A minimum air kerma irradiation of 50 mGy is recommended to minimise uncertainty.
</abstract>

Energy dependence of GafChromic LD-V1 film dose response to X-ray photons in the 60 to 180 kV range

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Polish Journal of Medical Physics and Engineering

The Journal of Polish Society of Medical Physics

 Polish Journal of Medical Physics and Engineering (PJMPE) is an official publication of the Polish Society of Medical Physics (established in 1965, member of IOMP and EFOMP). The...

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 Polish Journal of Medical Physics and Engineering (PJMPE) is an official publication of the Polish Society of Medical Physics (established...