rss_2.0Polish Journal of Medical Physics and Engineering FeedSciendo RSS Feed for Polish Journal of Medical Physics and Engineeringhttps://sciendo.com/journal/PJMPEhttps://www.sciendo.comPolish Journal of Medical Physics and Engineering Feedhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/64727d40215d2f6c89dca18e/cover-image.jpghttps://sciendo.com/journal/PJMPE140216The study of the impact of murmurs on heart sounds by using multiple signal classification pseudo-spectrumhttps://sciendo.com/article/10.2478/pjmpe-2024-0011<abstract> <title style='display:none'>Abstract</title> <p>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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00112024-06-30T00:00:00.000+00:00Radiological evaluation of mandibular alveolar reconstruction after retained third molar removal procedures using autogenous dentin matrix (ADM)https://sciendo.com/article/10.2478/pjmpe-2024-0010<abstract> <title style='display:none'>Abstract</title> <p><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.</p> <p><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.</p> <p><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.</p> <p><italic>Conclusions:</italic> This procedure seems to be useful for bone regeneration after the removal of the third molar.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00102024-06-30T00:00:00.000+00:00Book review: “Guidelines on professional ethics for medical physicists”, Training Course Series 78, Vienna, 2023https://sciendo.com/article/10.2478/pjmpe-2024-0012<abstract> <title style='display:none'>Abstract</title> <p>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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00122024-06-30T00:00:00.000+00:00From radiobiology to radiotherapy: dose homogeneity in cells after alpha irradiation in measurements and Monte Carlo simulationshttps://sciendo.com/article/10.2478/pjmpe-2024-0009<abstract> <title style='display:none'>Abstract</title> <p><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.</p> <p><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 <sup>241</sup>Am source is performed using radiochromic films. Additionally, a clonogenic cell survival assay is carried out for the DU145 cell line.</p> <p><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 <sup>241</sup>Am source demonstrate consistency with previously published findings.</p> <p><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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00092024-06-30T00:00:00.000+00:00Lung divisions for models of cardiopulmonary interaction – preliminary testshttps://sciendo.com/article/10.2478/pjmpe-2024-0007<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> The perfusion of a part of the lung depends on its distance from the pulmonary trunk (differences in vascular resistance) and on the horizontal plane (differences in hydrostatic pressure). The aim of this study was to determine the geometric parameters characterising their positions and sizes in order to analyse the diffusion of the ventilation/perfusion ratio.</p> <p><italic>Material and methods:</italic> A developed virtual respiratory system has been supplemented with an appropriate model of pulmonary circulation that uses a lung outline that is divided into parts based on an anatomical atlas and a CT image; it comprises a 3D geometric model of the lungs that was developed using the Inventor CAD software (Autodesk, Inc, San Francisco, USA). Each panel was divided into 2 horizontal and 8 vertical parts; the 16-part division was then modified.</p> <p><italic>Results:</italic> When taking human lungs as a research object and simulating their accompanying physical, biological, or biochemical phenomena, one necessary task is to construct a spatial model of the lungs that takes into account, and maintains awareness of, the limitations of the source of data that is relied upon. The developed modified geometric model of lung division turned out to be useful and was successfully applied to a virtual patient, among others, as part of the VirRespir project.</p> <p><italic>Conclusions:</italic> Finally, we can conclude that the virtual cardiorespiratory system thus elaborated may serve as a proper tool for the preliminary analysis of such complex interactions, considering the elaborated model of the lung’s divisions and its future improvements.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00072024-05-25T00:00:00.000+00:00Energy dependence of GafChromic LD-V1 film dose response to X-ray photons in the 60 to 180 kV rangehttps://sciendo.com/article/10.2478/pjmpe-2024-0006<abstract> <title style='display:none'>Abstract</title> <p><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.</p> <p><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.</p> <p><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.</p> <p><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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00062024-05-25T00:00:00.000+00:00Evaluation of changes caused by HR-HPV infection in squamous cell carcinoma of the head and neck using Raman microspectroscopy in combination with multivariate statistical analysishttps://sciendo.com/article/10.2478/pjmpe-2024-0008<abstract> <title style='display:none'>Abstract</title> <p><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.</p> <p><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.</p> <p><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.</p> <p><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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00082024-05-25T00:00:00.000+00:00The use of thermovision in the detection of asymptomatic facial inflammation – Pilot studyhttps://sciendo.com/article/10.2478/pjmpe-2024-0003<abstract><title style='display:none'>Abstract</title> <p><italic>Introduction: </italic>Asymptomatic inflammatory foci resulting from chronic dental infections or the presence of foreign bodies, e.g., in the sinuses, leading to serious local and systemic complications. These conditions, despite the absence of symptoms, are a source of bacterial, toxic, allergic, and neurogenic effects. Despite the developed radiological diagnostics in the form of pantomographic images and cone beam computed tomography (CBCT), thermal imaging is increasingly mentioned as an auxiliary tool in detecting and treating inflammatory foci of the craniofacial region. It is due that thermal imaging can bring indirectly metabolic information about studied tissues and thus allow the detection of early inflammatory lesions yet not invisible on X-ray diagnostics. The purpose of the study was to apply and validate a protocol for identifying asymptomatic inflammatory foci in the maxillofacial area using thermal imaging.</p> <p><italic>Material and methods: </italic>Patients referred to the institute were examined for the presence of inflammatory foci. Analysis of radiographs revealed asymptomatic foci in the maxillary sinus, which were associated with the presence of a displaced foreign body. Thermographic examinations were performed using a FLIR T540 thermal imaging camera.</p> <p><italic>Results: </italic>The obtained results showed a significant temperature difference between the suspected and opposite sinus. It was also confirmed that after the foreign body was removed from the sinus the temperature showed a dynamic decrease in time.</p> <p><italic>Conclusions: </italic>According to the study, thermography has the potential to become an essential diagnostic tool for inflammation of odontogenic origin. It offers non-invasiveness, safety, real-time imaging, painless and completely safe.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00032024-03-26T00:00:00.000+00:00Modified ResNet152v2: Binary Classification and Hybrid Segmentation of Brain Stroke Using Transfer Learning-Based Approachhttps://sciendo.com/article/10.2478/pjmpe-2024-0004<abstract><title style='display:none'>Abstract</title> <p><italic>Introduction: </italic>The brain is harmed by a medical condition known as a stroke when the blood vessels in the brain burst. Symptoms may appear when the brain’s flow of blood and other nutrients is disrupted. The World Health Organization (WHO) claims that stroke is the leading cause of disability and death worldwide. A stroke can be made less severe by detecting its different warning symptoms early. A brain stroke can be quickly diagnosed using computed tomography (CT) images. Time is passing quickly, although experts are studying every brain CT scan. This situation can cause therapy to be delayed and mistakes to be made. As a result, we focused on using an effective transfer learning approach for stroke detection.</p> <p><italic>Material and methods: </italic>To improve the detection accuracy, the stroke-affected region of the brain is segmented using the Red Fox optimization algorithm (RFOA). The processed area is then further processed using the Advanced Dragonfly Algorithm. The segmented image extracts include morphological, wavelet features, and grey-level co-occurrence matrix (GLCM). Modified ResNet152V2 is then used to classify the images of Normal and Stroke. We use the Brain Stroke CT Image Dataset to conduct tests using Python for implementation.</p> <p><italic>Results</italic>: Per the performance analysis, the proposed approach outperformed the other deep learning algorithms, achieving the best accuracy of 99.25%, sensitivity of 99.65%, F1-score of 99.06%, precision of 99.63%, and specificity of 99.56%.</p> <p><italic>Conclusions: </italic>The proposed deep learning-based classification system returns the best possible solution among all input predictive models considering performance criteria and improves the system’s efficacy; hence, it can assist doctors and radiologists in a better way to diagnose Brain Stroke patients.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00042024-03-26T00:00:00.000+00:00First implementation of quality control procedures on selected X-ray machines in South of Beninhttps://sciendo.com/article/10.2478/pjmpe-2024-0005<abstract><title style='display:none'>Abstract</title> <p><italic>Introduction: </italic>The use of X-ray equipment for medical diagnostic radiography procedures has increased due to advances and complexity of radiological procedures. Achieving good image quality while keeping exposure of workers, public and patient exposure to an acceptable level has become a prerequisite for the radiology department in order to comply with best international practices. The aim of this study was to undertake quality control measurement of seven (7) diagnostic radiography equipment in the south of Benin, the first of its kind.</p> <p><italic>Material and methods: </italic>Multifunction detector (Piranha) and beam alignment test tool were used to perform quality control tests on seven (7) X-ray units. The method used as well as the interpretation of the results was based on the American Association of Physicists in Medicine (AAPM), United States Food and Drug Administration (FDA), Healing Arts Radiation Protection (HARP), Institute of Physics and Engineering in Medicine (IPEM), International Atomic Energy Agency (IAEA) and Canadian Safety code 35 (S.C 35) recommendations.</p> <p><italic>Results: </italic>The quality control results showed that all X-ray equipment investigated were within standard limits for accuracy of exposure time below 10 ms; reproducibility of kVp, exposure time and dose output; specific dose-kVp<sup>2</sup> linearity; and specific dose-mAs linearity. Five (5) out of seven (7) diagnostic X-ray machines passed quality control tests such as X-ray beam alignment, exposure time above 10 ms and kVp accuracy. One (1) X-ray machine failed the quality control test of beam filtration at 70 kVp and above.</p> <p><italic>Conclusions: </italic>The findings of this study have provided baseline data for other radiology departments to embark on similar QA/QC activities, and also explore options for optimization of patient dose. However, there is a need to extend the study to cover more diagnostic X-ray machines throughout the country. It is anticipated that this would ultimately assist in improving radiation protection and safety during medical diagnostic radiological procedures.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00052024-03-26T00:00:00.000+00:00Analysis of the frequency and type of CT examinations performed in Poland in 2022https://sciendo.com/article/10.2478/pjmpe-2024-0002<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Computed tomography (CT) is one of the most widely used diagnostic procedures in modern medicine. Despite many technical improvements, CT still exposes patients to significantly higher doses of radiation than other methods of diagnostic imaging. The presented analysis of the number of CT scans performed in Poland in 2022 aims to designate priorities in the process of optimising radiation protection and makes it possible to identify those examinations and patient groups for which action is particularly justified.</p> <p><italic>Material and methods:</italic> The data presented is based on an analysis of the National Health Fund (NHF) database of medical services reimbursed in 2022. According to the NHF data, approximately 5.1 million CT examinations were performed. The coding of reimbursed medical procedures used by the NHF in 2022 included 45 different CT procedures.</p> <p><italic>Results:</italic> The highest ratio of the number of examinations performed to the number of patients was found in the age group 59-75 years (average 1.35). This ratio varied according to examination type and was closest to 1 for spine and extremities examinations (between 1.1 and 1.2 on average). Irrespective of patients’ age and type of examination, the proportion of female and male patients fluctuates around 50%. Approximately 82% of head and neck examinations are single-phase CTs. Examinations with two or more phases account for about 17% and less than 1%, respectively.</p> <p><italic>Conclusions:</italic> Over the past 10 years, both the number of CT scanners and the number of annually performed scans have doubled. Relative to the population size, this is a rate of about 22 scanners per one million people, an average level for European countries, ranging from a maximum of around 37 for Italy and Germany to around 20 for France, Spain, and Romania, according to Eurostat data.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00022024-02-10T00:00:00.000+00:00Advancing Auscultation Education: Signals Visualization as a Novel Tool for Enhancing Pathological Respiratory Sounds Detectionhttps://sciendo.com/article/10.2478/pjmpe-2024-0001<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Auscultation remains a pivotal diagnostic modality for various respiratory pathologies. To augment its clinical relevance, the continuous expansion of our understanding of pulmonary acoustics, coupled with the advancement of auscultation recording and analysis methodologies, is imperative.</p> <p><italic>Material and methods:</italic> We investigated how the bimodal presentation of auscultatory signals (sound and visual cue perception) influences the subjective efficacy of pathological respiratory sound detection, which is a critical step in the development of a new auscultation tool.</p> <p>Recordings of pediatric breath sounds were presented in three different forms - audio only, visual representation only (spectrogram) or audiovisual (both together). The F1-score, sensitivity and specificity parameters were calculated and compared to the gold standard (GS). Subsequent to the detection experiment, participants completed a survey to subjectively assess the usability of spectrograms in the procedure.</p> <p><italic>Results:</italic> Over 60% of all responders ranked the spectrogram as important (40.8%) or very important (21.1%). Moreover, 11.3% of all participants found this new form of presentation of auscultation results to be more useful than the evaluation of sound only. The addition of visual information did not statistically significantly change the evaluation of the sounds themselves, an observable trend implies that enhancing audio recordings with visualizations can enhance detection performance. This is evident in the 4 p.p. and 2 p.p. sensitivity increments for physicians and students, respectively, even without specialized visual training.</p> <p><italic>Conclusions:</italic> Our research findings indicate that the integration of spectrograms with conventional auditory assessment, albeit based on observed trends and survey responses, presents a promising avenue for improving the precision and quality of medical education, as well as enhancing diagnosis and monitoring processes.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2024-00012024-02-10T00:00:00.000+00:00Parametrization of subsegmental infarcts using high spatial resolution 2DSTE and synthetic ultrasonic datahttps://sciendo.com/article/10.2478/pjmpe-2023-0021<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> The purpose of this study was to assess the performance of a set of parameters in characterizing simulated infarcts in left ventricular (LV) models with variations in size and transmural extent.</p> <p><italic>Material and methods:</italic> The deformation of the LV models with different infarct sizes was simulated using the Finite Element Method. These simulations provided meshes that were used to generate synthetic ultrasonic data within the FIELD II package. The strain components (longitudinal and circumferential) were then estimated over small subsegments of the of segments 7 and 12 (according to 17-segment left ventricle segmentation standard proposed by the American Heart Association - AHA17), using a hierarchical block matching method. The strain maps obtained were utilized to calculate the Strain Drop Factor (SDF) maps, which represent the percentage ratio of strain observed in the subsegments of the studied model to that observed in the healthy model. Infarct segmentation was performed using these maps, and various parameters were derived, including Infarct Cross-Section Area (ICSA), relative ICSA, Transmurality Ratio (TR), Mean Infarct Transmurality (MIT), strain drop factor in the infarcted region (SDFi), and Strain Contrast (SC).</p> <p><italic>Results:</italic> The estimates of ICSA, SC, MIT, and SDFI showed good repeatability and demonstrated the ability to provide a quantitative assessment of the size and transmural extent of the infarcts.</p> <p><italic>Conclusions:</italic> The study findings suggest that the evaluated parameters, including ICSA, SC, MIT, and SDFI, can be reliably used to assess the size and transmural extent of infarcts. These parameters offer a quantitative approach for characterizing infarcts based on strain analysis and have the potential to contribute to the diagnosis and evaluation of myocardial infarctions.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00212023-12-15T00:00:00.000+00:00Automated differential diagnostics of respiratory diseases using an electronic stethoscopehttps://sciendo.com/article/10.2478/pjmpe-2023-0022<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> The outbreak of the coronavirus infection, which has escalated into a pandemic, has worsened the already unfavourable situation with respiratory system diseases in Ukraine. The burden on doctors has significantly increased, necessitating the exploration of simplified and expedited methods for conducting routine respiratory examinations. The research aims to describe a model for creating an automated differential diagnosis of respiratory noise using an electronic stethoscope, combining medical and clinical information about the types of respiratory noise characterizing the normal or pathological state of the respiratory system with a means of its information and technical processing.</p> <p><italic>Material and methods:</italic> The research methods were analysis of theoretical information about the types of respiratory noise, analysis of technical information for choosing an information technology tool for processing biological signals; synthesis of the results; modelling.</p> <p><italic>Results:</italic> The research resulted in a model of automated differential diagnosis based on the principle of auscultation, which includes the process of extracting the sound of air movement inside and outside the lungs and the classification of the extracted sounds. Automation of this process concerned only the classification of the extracted sounds since the principle of extraction itself was the same for both mechanical and automatic implementations.</p> <p><italic>Conclusions:</italic> The automatic classification process was intended to reduce the time of the procedure and reduce the influence of the human factor, eliminating the possibility of medical error. To implement the process, a deep machine learning method was used, the array of information for which was to be a created phonotheque of acoustic signals of the respiratory system, which would include all types of respiratory noise concerning normal or pathological processes in the body.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00222023-12-15T00:00:00.000+00:00Optical system for precise isocenter measurementhttps://sciendo.com/article/10.2478/pjmpe-2023-0019<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> The geometrical precision of the machines is essential for effective and safe radiotherapy. Methods currently used for the measurement of the mechanical isocenter have many limitations. In this work, the optical system NaviRation for very precise measurement of mechanical accelerator isocenter is described. The results of the measurement of the isocenter for linear accelerator are also presented.</p> <p><italic>Materials and methods:</italic> An optical system for measuring the accelerator isocenter was designed and built. The optical system consists of two cameras recording the target position made according to a patented Zeiss technology. About 1,200 pairs of images are recorded during the rotation of the gantry, collimator and treatment table. Mathematical analysis of these images makes it possible to determine the location of the target center during rotation. In order to verify the accuracy of the measurements, a device simulating rotational motion was designed. The measurement results were also verified at the Central Office of Measures. The system must be calibrated each time before taking measurements. In this article, we present the results of measurements for the Versa HD accelerator.</p> <p><italic>Results:</italic> The accuracy of determining the current position of the axis of rotation was 0.15 mm. The time of taking measurements of all rotations does not exceed 20 minutes. Measurement results for the Versa HD accelerator showed that this accelerator met the criteria described by TG142 of the AAPM. The diameter of the gantry, collimator and table isocenter spheres were 1.5 mm, 0.3 mm and 0.4 mm, respectively.</p> <p><italic>Conclusions:</italic> The system enables precise, fast and simple mechanical isocenter measurement of the gantry, collimator and treatment table. It is also possible to perform all tests related to the measurements of distances, e.g. quality control of distance indicator, and distance of the table movement. The isocenter is measured independently of the accelerator for which measurements are made.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00192023-11-17T00:00:00.000+00:00Dosimetric evaluation of VMAT automated breast treatment plans: Towards the establishment of an institutional plan acceptability criteriahttps://sciendo.com/article/10.2478/pjmpe-2023-0020<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> To evaluate the clinical suitability of the current facility-based treatment plan protocol in establishing acceptability criteria.</p> <p><italic>Material and methods:</italic> Automated Volumetric Arc Therapy (VMAT) treatment plans were retrospectively evaluated for intact breast and chest-wall cancer patients from January 2021 to January 2023.</p> <p><italic>Results:</italic> A total of 94 patients were planned and treated using automated contouring and VMAT planning technique. The number of patients planned and treated for intact breast and chest-wall were 41 (43.6%) and 53 (56.4%), respectively. The mean intact breast volumes for optimization (Brst_opt) receiving 95% and 105% of the prescribed doses were 92.80% ± 1.11 and 1.54% ± 1.02, respectively. Their corresponding mean chest-wall volumes for optimization (Chst_opt) were 90.65% ± 3.19 and 2.28% ± 2.99, respectively. For left-sided cases, the mean heart dose received was 4.61 Gy ± 1.76 and 5.18 Gy ± 1.55 for intact breast plans and that for chest-wall plans, respectively. The mean ipsilateral lung volume receiving 20 Gy of the prescribed dose was 12.22% ± 3.86 and 13.19% ± 3.74 for intact breast plans and chest-wall plans, respectively. For the Brst_opt and Chst_opt dose metrics were calculated; the mean homogeneity index (HI) was 0.14 ± 0.03 and 0.15 ± 0.04, mean uniformity index (UI) was 1.09 ± 0.03 and 1.11 ± 0.03, and mean conformity index (CI) were 0.92 ± 0.04 and 0.91 ± 0.04, respectively.</p> <p><italic>Conclusions:</italic> The dosimetric evaluation shows a good dose distribution in the target volumes with minimal doses to the organs at risk (OAR). Assessment of the current data affirms the clinical usefulness of the facility-adopted protocol in achieving quality treatment plans for intact breast and chest-wall irradiations. The establishment of plan acceptability criteria will help achieve improved overall treatment outcomes.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00202023-11-17T00:00:00.000+00:00Comparing eDQE and eNEQ metrics – is there an alternative approach to assessing image quality in digital mammography?https://sciendo.com/article/10.2478/pjmpe-2023-0018<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Early detection of breast cancer requires high-quality mammographic images that have been made possible by the introduction of new technologies, such as full-field digital mammography (FFDM). In this new study, we perform extended measurements to calculate effective detective quantum efficiency (eDQE) and introduce effective noise equivalent quanta (eNEQ). Our aim was to show how these two metrics relate to the image quality of two digital mammography systems.</p> <p><italic>Material and methods:</italic> Measurements were performed for a Siemens Mammomat Inspiration and a GE Senographe Pristina system. Each was equipped with an automatic exposure control (AEC) for use in a clinical setting. We used a polymethyl methacrylate (PMMA) phantom at thicknesses of 20, 30, 40 and 70 mm to cover the range of scatter conditions expected in mammography, with and without an anti-scatter grid. The Siemens system had an a-Se detector, and the GE system had an indirect-conversion detector. Measurements of Kerma were performed with Piranha Black 657 meter (RTI Electronics AB). The majority of our calculations were automated, using a modified version of our software.</p> <p><italic>Results:</italic> For the two mammographic systems evaluated, we characterized physical quality parameters, such as effective modulation transfer function (eMTF), effective normalized noise power spectrum (eNNPS), eDQE and eNEQ for a wide range of exposures, phantom thicknesses, with and without an anti-scatter grid. Results are presented as a function of spatial frequency. A contrast-detail analysis was performed with a CDMAM 3.4 phantom with dedicated software (CDMAM analysis 1.5.5, NCCPM) and a set of different PMMA phantoms.</p> <p><italic>Conclusions:</italic> We successfully demonstrated that the eNEQ metric can be used as a new option to evaluate image quality for images taken with and without a grid and with phantoms of different thicknesses for the Siemens and GE systems. These results were consistent with the results obtained from CDMAM.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00182023-09-26T00:00:00.000+00:00Evaluating the impact of anatomical changes on dose distributions in head and neck cancerhttps://sciendo.com/article/10.2478/pjmpe-2023-0017<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Thanks to modern IGRT procedures, it is possible to track changes in the patient's anatomy and thus calculate the dose distribution for the current anatomical conditions of the patient. This allows the scheduled dose to be compared with the delivered dose. In the case of large discrepancies, it is possible to improve the treatment plan. Radiotherapy, during which the treatment plan is modified, resulting from changes in anatomy, is referred to as adaptive radiotherapy.</p> <p><italic>Material and methods:</italic> This study was performed for 30 patients with H&amp;N cancer at the University Hospital in Zielona Góra. All patients were treated with VMAT. The Simultaneous Integrated Technique was used. In each treatment session, set-up verification was performed. Alternating every other day, the CBCT and two orthogonal portal images were made, and position correction prior to each session was performed. For all patients, new planning CT was made after the 11th and 22nd treatment sessions. Dose distributions with the initial plan on CT11 and CT22 were calculated. The initial dose-volume histograms DVH0 were compared with dose-volume histograms DVH11 and DVH22 calculated on CT11 and CT22.</p> <p><italic>Results:</italic> We compared the dose distribution in the CTVs and in the most important organs at risk obtained for initial anatomy and dose distributions calculated with the initial plan on the CTs performed after the second and the fourth week of irradiation. The differences between mean doses and V95% to GTV obtained for the initial CT and two other CTs were small. For a few CTs, the values of V95% were smaller by more than 5% points. In most patients, the mean dose in salivary glands increased during treatment.</p> <p><italic>Conclusions:</italic> Anatomical changes occurring during radiotherapy in patients with head and neck cancers have little influence on the dose deposited in the Clinical Target Volume. Adaptive therapy may be of particular importance if relapse occurs and re-irradiation.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00172023-09-26T00:00:00.000+00:00Vascular stiffness in cold pressor test hyper-reactorshttps://sciendo.com/article/10.2478/pjmpe-2023-0016<abstract> <title style='display:none'>Abstract</title> <p><italic>Background:</italic> The cold pressor test (CPT) is a sympathoexcitatory manoeuvre to measure cardiovascular hyperactivity which may be a sign of future hypertension development.</p> <p><italic>Aims and Objectives:</italic> To evaluate the vascular stiffness background among healthy CPT hyper-reactor (H-R) males and age and gender-matched normo-reactors (N-R).</p> <p><italic>Methods:</italic> The study was carried out in 34 healthy young males aged 19 years old. Five minutes of recordings of left middle fingertip digital pulse wave (DPW) signals (through a piezoelectric finger pulse transducer) were registered. This was followed by the application of a cold pressor. Blood pressure (BP) and heart rate (HR) during CPT were recorded, and the individuals were divided into N-Rs and H-Rs. Vascular stiffness indices like pulse wave velocity (PWV), B/A wave ratio, pulse rising time (PRT, or crest), large artery stiffness index (SI), and pulse width (PW) were compared between H-Rs and N-Rs.</p> <p><italic>Results:</italic> No significant differences were observed between the two groups across all studied parameters.</p> <p><italic>Conclusion:</italic> The results suggest there was no difference in the vascular stiffness background between CPT H-R and N-R individuals.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00162023-07-29T00:00:00.000+00:00Complexity analysis of VMAT prostate plans: insights from dimensionality reduction and information theory techniqueshttps://sciendo.com/article/10.2478/pjmpe-2023-0015<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Volumetric Modulated Arc Therapy (VMAT) is a state-of-the-art prostate cancer treatment, defined by high dose gradients around targets. Its unique dose shaping incurs hidden complexity, impacting treatment deliverability, carcinogenesis, and machine strain. This study compares various aperture-based VMAT complexity indices in prostate cases using principal component and mutual information analyses. It suggests essential properties for an ideal complexity index from an information-theoretic viewpoint.</p> <p><italic>Material and methods:</italic> The following ten complexity indices were calculated in 217 VMAT prostate plans: circumference over area (CoA), edge metric (EM), equivalent square field (ESF), leaf travel (LT), leaf travel modulation complexity score for VMAT (LTMCSV), mean-field area (MFA), modulation complexity score (standard MCS and VMAT variant MCSV), plan irregularity (PI), and small aperture score (SAS<sub>5mm</sub>). Principal component analysis (PCA) was applied to explore the correlations between the metrics. The differential entropy of all metrics was also calculated, along with the mutual information for all 45 metric pairs.</p> <p><italic>Results:</italic> Whole-pelvis plans had greater complexity across all indices. The first three principal components explained 96.2% of the total variance. The complexity metrics formed three groups with similar conceptual characteristics, particularly ESF, LT, MFA, PI, and EM, SAS<sub>5mm</sub>. The differential entropy varied across the complexity metrics (PI having the smallest vs. EM the largest). Mutual information analysis (MIA) confirmed some metrics’ interdependence, although other pairs, such as LTMCSV/SAS<sub>5mm</sub>, LT/MCSV, and EM/SAS<sub>5mm</sub>, were found to share minimal MI.</p> <p><italic>Conclusions:</italic> There are many complexity indices for VMAT described in the literature. PCA and MIA analyses can uncover significant overlap among them. However, this is not entirely reducible through dimensionality reduction techniques, suggesting that there also exists some reciprocity. When designing predictive models of quality assurance metrics, PCA and MIA may prove useful for feature engineering.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/pjmpe-2023-00152023-07-29T00:00:00.000+00:00en-us-1