Polish Journal of Medical Physics and Engineering Feed

Optimization of a Dosimetric Quality Assurance System for a Medical Linear Accelerator under ISO/IEC 17025 Accreditation: Measurement Stability Assessed by Uncertainty Analysis

Thu, 02 Jul 2026 00:00:00 GMT

BackgroundAccurate dosimetry is essential for safe and effective radiotherapy. Although international guidelines are available, routine clinical practice does not always include a comprehensive evaluation of measurement uncertainty and methodological stability.PurposeThis study presents a structured quality assurance system for medical linear accelerators, with particular emphasis on measurement uncertainty analysis as a tool for assessing the stability and robustness of dosimetric procedures.Materials and MethodsThe study was conducted on a fleet of 10 Varian linear accelerators operating in photon and electron energy ranges. Quality control procedures were developed in accordance with international recommendations (IAEA, AAPM, ESTRO) and implemented within an accredited system compliant with PN-EN ISO/IEC 17025. Measurement uncertainty was evaluated using Type A and Type B approaches, including repeatability, reproducibility, and long-term stability analyses.ResultsThe implemented framework enabled quantitative evaluation of measurement uncertainty and confirmed compliance with acceptance criteria for all analyzed parameters. Reduced measurement variability and improved repeatability were observed across all monitored procedures.ConclusionsThe implementation of an accredited dosimetric quality assurance system significantly improved measurement consistency and clinical safety. Measurement uncertainty analysis proved to be an effective tool for monitoring stability and minimizing the risk of dosimetric errors in radiotherapy.

Design and construction of in-house source holder for assaying the source strength of I-125 seed, model #: STM1251

Thu, 02 Jul 2026 00:00:00 GMT

IntroductionAssessment of the source strength is a mandatory task performed by medical physicists to ensure accurate, optimal dose calculation and delivery to a patient undergoing brachytherapy (BT) treatment. Furthermore, there is the need to verify source strength provided by a vendor of BT sources before their clinical use to ensure traceability to international standards such as the American Association of Physicists in Medicine and European Society for Therapeutic Radiology and Oncology (AAPM-ESTRO) recommendations.Material and methodsAn in-house source holder that could be accommodated within the well-type ionisation chamber (WTIC) was designed and constructed from Perspex (PMMA). The constructed source holder was designed to hold a cartridge of I-125 BT seed within the WTIC to facilitate batch source strength measurement. The source holder ensuring reproducibility of I-125 seed placements during source calibration, also enabled placement of a cartridge such that the point of concentration of activity of I-125 seeds coincided with the calibration point.ResultsThe mean percentage deviation of the source strengths was (1.155 ± 0.854) % which agrees with AAPM-ESTRO recommendations. For all batches of I-125 seeds investigated in this work, we found that the WTIC response was linear.ConclusionsWe, therefore, recommend that the methodology adopted to assay the source strength of Bard I-125 seed (model #: STM1251) be used by the BT departments offering low dose rate permanent interstitial BT services.

Augmentation of Brachial Reactive Hyperemia by Local Forearm Heating: A plethysmography-Based Comparison with the Standard Room-Temperature Protocol

Thu, 02 Jul 2026 00:00:00 GMT

IntroductionReactive hyperemia (RH) is widely used to assess microvascular endothelial function, but its magnitude may be limited when performed on a normally perfused, non-heated forearm. Local skin heating to 43.5°C produces sustained nitric oxide–dependent vasodilation and may augment the RH response.Material and methodsTwenty healthy adult males (non-smokers, medication-free) underwent standard RH induced by 5-min brachial artery occlusion followed by 3 min reperfusion. ECG and bilateral fingertip plethysmography digital pulse waves were recorded to derive pulse transit time (PTT) and finger-to-finger pulse-arrival-time difference (f–f ΔT). In 11 of these participants, the forearm was then heated with an electric heat pad to 43.5 ± 0.4°C for 25–30 min, and RH was repeated. Indices were calculated from 60–80 cardiac cycles during the first two minutes of reperfusion.ResultsAt room temperature, RH increased PTT by about 5%–6% and markedly increased f–f ΔT, consistent with improved distal perfusion. When RH was repeated after local heating, the reactive hyperemia index was significantly higher (about 1.5-fold, p < 0.007), indicating that prior heating enhanced the hyperemic response. In contrast, heated RH did not produce further increases in PTT or f–f ΔT compared with RH at room temperature, suggesting dissociation between enhanced microvascular recruitment and conduit-level stiffness changes.ConclusionsPerforming RH after local forearm heating at 43.5°C amplifies plethysmography-derived hyperemia indices compared with the conventional room-temperature test, mainly by enhancing the endothelial and microvascular component rather than further reducing arterial stiffness. Thermal priming may improve the sensitivity of plethysmography-based endothelial assessment in physiological studies.

Geometrical prediction model for late rectal bleeding in radiotherapy of prostate cancer

Tue, 02 Jun 2026 00:00:00 GMT

IntroductionEffective prostate radiotherapy requires integrating radiobiological parameters like the α/β ratio with planning factors such as dose gradients, margins, and adaptive strategies. Predicting late rectal bleeding (LRB) remains challenging but essential for optimizing safety. This study presents a preliminary model to predict LRB using only patient imaging data, offering a practical tool to assess toxicity risk daily and support personalized treatment decisions.Material and methodsWe retrospectively analyzed a cohort of 116 prostate cancer patients treated with radiotherapy, divided into standard (2.0 Gy/fraction) and m-Hypo (2.5 Gy/fraction) groups. The toxicity endpoint was late rectal bleeding (LRB); its incidence was characterized and the rectal α/β ratio estimated and used in subsequent analyses. To assess relationships between toxicity and patient/treatment/planning factors, six metrics were defined: one geometric parameter, P₀, representing the rectum–PTV intersection volume, and five DVH parameters. We combined these findings in a sector analysis using linear and logistic models between selected parameters.ResultsLate rectal bleeding (LRB) occurred in 11% of the standard group and 26% of the hypofractionated group. The estimated α/β for the LRB endpoint was 1.5 Gy (95% CI: 0–12 Gy). Dose–volume metrics P₂ and P₄ were significantly associated with binary toxicity in logistic regression. Sector analysis using P₀ as the independent variable identified regions with high toxicity rates (>40%), predominantly within the hypofractionated cohort, as well as regions with negligible toxicity.ConclusionsA linear relationship between the P₀ parameter and toxicity predictors (P₃, P₄) suggests that volumetric parameters can be integrated into patient-specific risk assessments and treatment planning. Our findings indicate that regions with P₀ < 10 cc (L1, H1) may tolerate variations in fractionation and dose, while regions with higher P₀ (L2, H2) require cautious strategies such as dose reduction, margin optimization, and advanced imaging to minimize toxicity. This framework provides a foundation for personalized radiotherapy optimization, pending further validation.

Comparative Evaluation of ICG Signal Processing Techniques for Detecting Caffeine-Induced Hemodynamic Changes

Tue, 02 Jun 2026 00:00:00 GMT

IntroductionThe study aims to evaluate the effectiveness of three methods for detecting fiducial points in the impedance cardiography (ICG) signal in the context of subtle hemodynamic changes induced by caffeine intake. The compared approaches include: time-domain detection (CPDA), extrema-based analysis (EBA) and wavelet transform analysis (WTA).Material and methodsThe study involved 20 healthy volunteers, with cardiovascular parameters such as stroke volume (SV), cardiac output (CO) and heart rate (HR) assessed before and after coffee consumption.ResultsComparative analysis showed that WTA provided the lowest variability of hemodynamic parameters, with standard deviations of ±1.54 for CO and ±21.82 for SV, compared with ±1.76 and ±33.77 for EBA and ±1.92 and ±43.59 for CPDA, respectively. Repeated-measures ANOVA revealed significant differences between methods in HR estimation after decaffeinated coffee consumption (p = 0.001). Post-hoc analysis showed significant differences between EBA and CPDA (p = 0.0006), EBA and WTA (p = 0.0003), and EBA and pressure-gauge measurements (p = 0.002). Additional analyses confirmed significant effects of beverage type and method on HR (p = 0.003 for decaffeinated coffee; p = 0.02 for caffeinated coffee) and on CO after decaffeinated coffee (p = 0.03).ConclusionsOverall, the wavelet-based approach demonstrated the greatest robustness to noise and the highest sensitivity to subtle physiological changes associated with caffeine intake. This work highlights the importance of selecting appropriate algorithms for remote cardiovascular monitoring and personalized healthcare and demonstrates their sensitivity to capture subtle changes induced by caffeine ingestion.

Power-Based Optimization of Ventilation Frequency Without Compliance or Resistance Measurements: A Simulation Study

Tue, 02 Jun 2026 00:00:00 GMT

BackgroundMechanical ventilation remains a life-saving intervention but carries risks such as barotrauma, volutrauma, ergotrauma, and hemodynamic disturbances. Modern ventilators incorporate adaptive strategies to minimize the work of breathing (WOB), often relying on measurements of respiratory resistance and compliance. However, such measurements are prone to error and often unavailable in real time. This study presents a novel adaptive ventilation concept that dynamically identifies the optimal ventilation frequency minimizing WOB per minute without requiring resistance or compliance measurements.Material and methodsUsing a validated hybrid respiratory simulator, we conducted simulation experiments across three representative lung conditions: normal mechanics, decreased compliance, and increased resistance. The system conceptually searched for the ventilation frequency minimizing WOB/min while maintaining constant alveolar ventilation, with the optimization process emulated manually in this proof-of-concept study.ResultsResults confirmed that WOB/min follows a parabolic function of frequency, with optimal frequencies found at 18, 21, and 12 breaths per minute for normal, restrictive, and obstructive patterns, respectively. Importantly, the optimal frequencies aligned with ranges observed in clinical studies of adaptive support ventilation. Furthermore, the system demonstrated natural variability in ventilation rate and tidal volume, which may contribute to alveolar recruitment.ConclusionOur findings validate the concept of energy-based optimization of ventilation independent of online lung mechanics assessment. The proposed method is robust, physiologically grounded, and may become suitable for integration into next-generation intelligent ventilators after full automation of the adaptive algorithm. Future work will focus on full automation of the adaptive algorithm and its evaluation in preclinical and clinical studies targeting WOB and mechanical power minimization.

CT-based lung geometry for high-resolution modelling of cardiopulmonary interaction

Tue, 02 Jun 2026 00:00:00 GMT

BackgroundAccurate representation of lung geometry is a prerequisite for reliable computational modelling of cardiopulmonary interaction, particularly for simulating regional ventilation–perfusion (V/Q) heterogeneity driven by gravity and vascular anatomy. Most existing models either simplify lung geometry or lack explicit spatial anchoring to physiological reference points.Material and methodsIn this study, diagnostic computed tomography (CT) images were used to reconstruct anatomically faithful lung geometry and subdivide both lungs into 80 spatially coherent regions. For each region, a set of geometric parameters was extracted, including volume and three-dimensional coordinates of the centre of gravity relative to the pulmonary trunk and to horizontal and vertical reference planes. Image preprocessing, vectorization, and geometric reconstruction were performed using widely available software tools, and the resulting feature matrix was implemented in a mathematical model of cardiopulmonary interaction within a virtual patient environment.ResultsThe CT-based approach enabled precise localization of the pulmonary trunk and consistent definition of a global coordinate system, allowing simultaneous representation of vertical (gravitational) and radial (vascular resistance–related) perfusion gradients. Example simulations demonstrated physiologically plausible distributions of ventilation and perfusion across lung regions, including reduced ventilation in dependent areas and heterogeneous perfusion within iso-gravitational planes.ConclusionsCT-based reconstruction of lung geometry from diagnostic images enables high-resolution regional partitioning and generation of a robust geometric matrix suitable for cardiopulmonary simulations. Although limited to a single anatomical dataset and static geometry, the presented model provides a solid foundation for future integration of regional mechanics, dynamic deformation, and validation with functional imaging, supporting advanced research, educational, and clinical applications.

The Utility of the TKEO Parameter in the assessment of thoracic respiratory movements

Tue, 17 Mar 2026 00:00:00 GMT

IntroductionChronic obstructive pulmonary disease (COPD) and dysphonia are prevalent disorders associated with altered respiratory patterns, posing significant diagnostic and therapeutic challenges. Accurate and efficient assessment of thoracic respiratory movements is essential for individualized therapy and monitoring. The Teager-Kaiser Energy Operator (TKEO), originally developed for speech analysis, offers a single-parameter approach to evaluate both amplitude and frequency characteristics of biosignals. This study aimed to determine the utility of TKEO in assessing thoracic respiratory patterns in healthy individuals, COPD patients, and those with dysphonia.Material and methodsSixty-one participants were enrolled: 30 healthy controls, 16 with COPD, and 15 with dysphonia. Thoracic and abdominal respiratory movements were recorded using Respiratory Inductive Plethysmography (RIP) in both standing and seated positions. The TKEO parameter was calculated from the displacement signals, and its values were compared with conventional respiratory parameters (inspiratory and expiratory depths) obtained via RIP. Statistical analysis included the Kruskal-Wallis test and Spearman’s rank correlation to assess group differences and parameter relationships.ResultsIn the seated position, TKEO values and conventional respiratory parameters significantly differentiated between healthy subjects, COPD, and dysphonia groups (p < 0.01). Healthy and COPD subjects exhibited higher diaphragmatic activity, while dysphonia patients showed a dominant upper rib pattern. TKEO values closely paralleled traditional respiratory measures, with strong to very strong positive correlations observed across all groups and positions (Spearman’s ρ, p < 0.001). In the standing position, group differences were less pronounced, but TKEO still reflected underlying respiratory patterns.ConclusionsTKEO is a sensitive and efficient parameter for assessing thoracic respiratory movements, correlating strongly with established respiratory metrics. Its application may accelerate and refine the diagnosis of respiratory pattern disorders in clinical practice. Further research should explore TKEO’s integration with artificial intelligence-based diagnostic tools and its utility in larger, age-matched cohorts.

Breast Density Patterns and Their Association with BI-RADS Categories among a Large Cohort of Ghanaian Women

Tue, 17 Mar 2026 00:00:00 GMT

IntroductionBreast cancer remains a major global health challenge, with Africa and other developing countries experiencing its greatest impact. Knowledge of breast density (an independent risk factor) is essential for early breast cancer diagnosis. However, such data is scarce across Africa and absent in Ghana. The aim of this work was to investigate the association between mammographic breast density patterns and BI-RADS assessment categories among women in Ghana.Material and methodsA retrospective cross-sectional study was conducted on 2,108 women who underwent mammography between October 2011 and December 2022. Breast density was visually assessed by radiologists using the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS). Associations between breast density, age, and BI-RADS assessment categories were analysed using Fisher’s Exact Test.ResultsBreast density category B (scattered fibroglandular tissue) was most common (44%, n = 935), followed by category A (almost entirely fatty; 39%, n = 821), category C (heterogeneously dense; 16%, n = 397), and category D (extremely dense; 1%, n = 23). More than 50% of all categories received benign diagnoses (BI-RADS 2), while less than 10% recorded negative diagnoses (BI-RADS 1). Higher-density categories demonstrated a greater proportion of suspicious and malignant findings: in category D, 17% were BI-RADS 3, 17% BI-RADS 4, and 13% BI-RADS 5, compared to lower proportions in categories A and B. Confirmed malignancies (BI-RADS 6) were observed across categories A–C (1% each). A significant association was found between breast density and cancer diagnoses (p < 0.05), as well as between age and breast density (p < 0.05).ConclusionThere is a significant association between breast density and BI-RADS assessment categories, with lower breast density observed in older women, a finding consistent with published literature. These results highlight the need for tailored breast cancer screening strategies in Ghana.

Optimizing Isocenter Accuracy in ExacTrac Dynamic®: Daily Verification and Quality Assurance for Reliable Patient Positioning

Tue, 17 Mar 2026 00:00:00 GMT

IntroductionAdvances in teleradiotherapy, such as SRS and SBRT, have improved treatment by delivering higher doses in fewer sessions, reducing duration, and sparing healthy tissue. These techniques require precise patient positioning, achieved through systems like SGRT (surface tracking) and IGRT (X-ray imaging). The ExacTrac Dynamic system (Brainlab AG, Germany) combines both, offering submillimetric accuracy for cranial radiotherapy. This study evaluates its quality assurance (QA) protocols, focusing on calibration, accuracy, and clinical performance.Background and PurposeSRS and SBRT allow targeted treatment with minimal margins, reducing complications. Precise alignment is essential, particularly for cranial cases. The study assesses the QA processes of the ExacTrac Dynamic system and evaluates its accuracy and reliability.ResultsDaily logs revealed differences between Surface Tracking and X-ray imaging. X-ray was more reliable, especially for longitudinal translational deviations, while Surface Tracking was affected by thermal artifacts. Rotational deviations remained within tolerance, with the largest shifts in yaw. Histogram analysis showed skewed distributions, underscoring the importance of combining both methods and regular QA.ConclusionRegular QA and recalibration of the ExacTrac Dynamic system are essential to address discrepancies between SGRT and X-ray methods. X-ray offers greater precision, while Surface Tracking is prone to environmental artifacts. Combining SGRT and IGRT ensures accuracy but requires consistent QA to maintain treatment precision.

Biomaterials for hip joint implants with particular emphasis on titanium and its alloys

Tue, 17 Mar 2026 00:00:00 GMT

IntroductionThe primary objectives of replacing a natural hip joint with a prosthesis are to restore the function of a joint damaged by degenerative disease, advanced rheumatoid conditions, or mechanical injury, to eliminate pain caused by pathological joint changes, and to re-establish proper load transfer. Additionally, the procedure aims to restore motor functions, enabling the patient to move and perform essential daily activities such as walking, lifting, and carrying objects.Material and methodsThis article outlines the requirements for biomaterials used in the components of hip joint prostheses, presents various groups of titanium alloys, and describes their properties in detail. Special attention is paid to titanium and titanium alloys, including their mechanical and physical characteristics. The influence of Young’s modulus on fretting and fatigue cracking in metallic alloys used in modular prosthetic components is also examined.ResultsTitanium alloys are generally not used for femoral heads due to their poor tribological performance. Without appropriate surface modification, titanium alloys are unsuitable for use in articulating components such as heads and acetabular cups, as they exhibit low abrasion resistance. They also demonstrate limited resistance to fretting damage, particularly at the junctions between the stem neck and head in modular prostheses.ConclusionsTo improve abrasion resistance, diffusion-based thermochemical surface treatments can be employed to harden the material’s outer layer. However, the issue of fretting-induced damage at the neck region of hip endopros-theses remains unresolved. This problem is critical, as it often leads to corrosion and fatigue cracking of the stem neck, ultimately requiring prosthesis revision and incurring significant clinical and economic consequences. Plasma (ionic) nitriding has been shown to enhance surface properties such as hardness, wear resistance, resistance to fretting damage, fretting corrosion, and fretting fatigue, as well as overall fatigue cracking resistance.

Implementation and Application of the IORT INTRABEAM 600 System – Commissioning Measurements and Independent Treatment Verification

Tue, 17 Mar 2026 00:00:00 GMT

IntroductionIntraoperative radiotherapy (IORT) delivers a single high-dose radiation fraction directly to the tumor or tumor bed during surgery, minimizing exposure to healthy tissue. The INTRABEAM 600 system, with its compact design and low-energy X-rays, requires thorough commissioning and quality assurance. This study performs dosimetric measurements, establishes an independent verification method, and compares Calibration v4.0 and TARGIT approaches to ensure accurate, safe, and reliable IORT delivery, supporting improved clinical outcomes.Materials and MethodsThe INTRABEAM 600 system delivers low-energy X-rays via a XRS generator for precise intraoperative radiotherapy. Commissioning involved depth dose rate measurements in a water phantom using ionization chambers, with probe tip positioned along X, Y, and Z axes. Dose rates were determined using Calibration v4.0 and TARGIT methods, correlated via a conversion function. QA checks included PAICH output, IRM baseline, and isotropy verification, ensuring accurate, reproducible treatment delivery.ResultsDynamic offset analysis showed minimal deviations, confirming accurate beam targeting. The Output Check confirmed stable system performance. Depth dose rate curve measurements revealed a mean difference of -1.3 ± 1% from certification data. Treatment time calculations using spherical applicators showed minor differences between INTRABEAM600 and radiance, with the largest at -1.9 ± 1.1% for the 20 mm applicator. TARGIT results were similar, with the largest differences at -1.8 ± 0.6% for the 15 mm and 20 mm applicators.ConclusionComprehensive commissioning and QA confirmed that the INTRABEAM 600 system is stable, precise, and clinically reliable. Dynamic offsets showed minimal deviations, verifying correct beam alignment, while Output Check tests confirmed XRS generator stability. Depth dose rate measurements agreed closely with certification data −1.3 ± 1.0%. Treatment time comparisons using Calibration v4.0 and TARGIT showed minor discrepancies, largest for small applicators (15–20 mm). Independent verification and radiance simulations support accurate dose delivery.

Effect of Clinical Acquisition Parameters to Dose Distribution Adaptive Radiotherapy in Two Institutions

Tue, 17 Mar 2026 00:00:00 GMT

IntroductionThis work aims to examine image quality and dose based on Cone Beam Computed Tomography using phantoms in the two institutionsMaterials and methodsThe Rando and Catphan Phantoms were scanned using identical image acquisition and reconstruction settings with Cone Beam Computed Tomography (CBCT). The calibration curve was obtained based on the Hounsfiled Unit (HU) values on the Gammex 467 Phantom.. This study was performed at two institutions equipped with the same CBCT and CT Simulator. The acquisition with CBCT HU values that closely matched CT HU values employed a protocol of 120 kVp, Bowtie Filter (F1), and 80 mA for 10 ms within a Small Field of View (FOV). For the Medium FOV, the closest protocol also used 120 kVp, a Bowtie Filter, and 64 mA for 32 ms, while for the Large FOV, it was set at 120 kVp, F1, and 50 mA for 40 ms. The parameters chosen from each reconstructed FOV served as calibration curves for planning head and neck and pelvic treatments. Planning followed the Task Group 119 recommendations incorporating IMRT techniques.ResultThe best acquisition protocol for accurate dose calculations in head and neck cases is Field of View Small with 20 collimation using bowtie filter with 120 kVp and 80 mA for 10 ms/frame, while for Pelvic cases, it is FOVMedium with 20 collimation using bowtie filter with 120 kVp and 64 mA for 32 ms/frame. In image quality assessments, the lowest contrast visibility and uniformity scores were observed with FOV Small with 20 collimation using bowtie filter with 120 kVp and 80 mA for 10 ms/frame, using the reconstruction parameters Quality Image (QI) of 0.65% and 1%.ConclusionSelecting the appropriate CBCT acquisition protocol can lead to favorable outcomes in both dose calculation and image quality.

A novel agar-based phantom for quality control of medical ultrasound devices

Wed, 17 Dec 2025 00:00:00 GMT

IntroductionRegular quality control and verification of medical ultrasound systems are essential for maintaining high diagnostic accuracy. However, the high cost of commercial phantoms often limits their use, particularly in smaller healthcare facilities. This study aimed to develop a low-cost agar-based phantom and evaluate its suitability for ultra-sound quality control.Material and methodsThe phantom was constructed using a plexiglass container filled with a 30 g/L agar solution. Test structures of different sizes were incorporated using nylon threads, small wooden pieces, and agar mixed with graphite. Measurements were performed with Voluson 730 Expert and GE Healthcare LOGIQ α 100 systems.ResultsQuality control tests included assessments of image uniformity, contrast resolution, spatial resolution, dead zone, maximum penetration depth, and geometric accuracy. The presence of targets of varying sizes enabled evaluations consistent with international quality assurance guidelines.During testing, several image artifacts and minor malfunctions were observed, likely resulting from trapped air bubbles or transducer imperfections, which could influence image interpretation. Nevertheless, the results indicate that the developed phantom performs reliably for key ultrasound quality control procedures.ConclusionsIts simple design, inexpensive materials, and adaptability make it particularly suitable for routine checks and training applications. Furthermore, its easy reproducibility allows customization for different clinical needs and equipment types. Overall, this study demonstrates that an agar-based phantom can serve as an effective, low-cost alternative to commercial models, supporting systematic quality control in ultrasound imaging. Such accessible solutions may help standardize testing procedures, enhance diagnostic consistency, and ultimately improve patient safety.

Tailored software for post-radiotherapy lung radiomics analysis

Wed, 17 Dec 2025 00:00:00 GMT

IntroductionRadiotherapy is a crucial method of treating lung cancer. However, potential toxicity such as radiation-induced lung injury (RILI) must be considered. In order to quantitatively describe different forms of RILI, a next generation of a previously discussed system has been developed to analyse the subsequent series of CT scans performed by patients during radiation therapy and post-RT follow-up.Materials and methodsA 3D CT scan registration module has been developed as part of the system. The analysis management module has been expanded compared to previous versions of the system. The environment has been prepared and the system has been deployed. In order to determine the effectiveness of the system, 1598 analyses, based on automated image pre-processing (registration and segmentation) and first-order delta-radiomics features, have been performed on a data set from 50 Patients.ResultsThe efficiency of the execution of the analysis was evaluated in terms of time, including a breakdown into individual stages of the pipeline. The results of the analyses were visualised and exported to a CSV file, then evaluated from a clinical perspective.ConclusionsThe system allows, thanks to the use of a 3D registration algorithm, to analyse changes more accurately than before, and thanks to the use of a more flexible architecture, to introduce subsequent registration and calculation algorithms more easily. The current main research and development areas of the system include the extension of the analytical capabilities of the system in the field of radiomics and the expansion of the number of image analysis algorithms used within the system.

Analysis of daily changes in volume and predicted doses for critical organs and the prostate during radiotherapy

Wed, 17 Dec 2025 00:00:00 GMT

IntroductionThe analysis of the differences in the daily volumes and the predicted dose to the actual dose in the bladder, rectum, and targets in prostate radiotherapy is presented.Material and methodsThe analysis was performed for 30 patients treated with prostate cancer. Precision treatment planning system was used to calculate the dose distribution. Patients were set up on the treatment table in the treatment position every day. kVCT images were acquired. kVCT images were imported into the PreciseART module. Organs at Risk and the prostate (PTV) volumes were copied onto these daily actual CT images and then automatically deformed to their current shapes. They were used to recalculate the updated therapeutic treatment plan. 726 CT examinations were analyzed. The volumes and dose values from clinical treatment plan have been used as reference values for the PTV, bladder, and rectum. Changes in volumes and doses for reference values and daily CT images were analyzed.ResultsThe average daily changes in PTV, bladder and rectum volumes ranged from -0.3% to 14.4%, -21.7% to 32.5% and -10.5% to 32.5%, respectively. Corresponding standard deviations ranged from 1.0% to 5.5%, 4.9% to 35.5% and 5.8% to 25.2%, respectively. Corresponding median values ranged from -0.2% to 14.1%, -22.0% to 37.8% and -10.9 to 32.8, respectively. The average daily changes in PTV, bladder and rectum projected doses ranged from -1.4% to 2.9%, -9.0% to 24.8% and -25.4% to 15.9%, respectively. Corresponding standard deviations ranged from -1.4% to 2.6%, 0.0% to 14.8% and 0,0% to 17,2%, respectively. Corresponding median values ranged from -1.5% to 2.7%, -8.8% to 28.7% and -25.9% to 17.2%, respectively.ConclusionsQualitative data analysis showed that the greatest differences in volumes and doses occurred for these structures. For the prostate, these changes were lower than for other organs.

Proposal of method dosimetry to realize in-vivo measurements in skin surface brachytherapy

Wed, 17 Dec 2025 00:00:00 GMT

IntroductionSkin surface brachytherapy is a highly targeted radiation therapy used for treating superficial malignancies, offering precise dose delivery with minimal impact on surrounding healthy tissues. However, in-vivo dose verification remains a critical challenge in brachytherapy. Thermoluminescent dosimeters (TLDs) provide a promising solution for increased precision of dose delivery to cancer patients. This study proposes a TLD-based method to assess radiation exposure during skin surface brachytherapy, with a particular focus on TLDs calibration process and validation leading to the opportunity to reduce dose of radiosensitive structures such as the lens of the eye.Materials and MethodsTL detectors were calibrated using both an Iridium-192 (¹⁹²Ir) source and a 6 MV photon beam, incorporating correction factors to enhance measurement accuracy. During measurements, TLDs were positioned on the skin surface of the anthropomorphic head phantom to absolute point dose measurements. The measured TLD doses were compared with treatment planning system (TPS) calculations to validate the proposed method. Additionally a specific analysis was conducted to compare the radiation exposure of the eye lens with and without the use of a protective eye shield with use of the anthropomorphic head phantom.ResultsTLDs response to a uniform radiation dose were within the range of ±10% of the mean. For the method of calibration used 6MV photons from medical linear accelerator, a value 3% for the energy correction factor was applied to account for the difference in sensitivity of the TLDs in 192Ir and 6MV. For both calibration methods, with used appropriate calibration factors, obtained dose values for the anthropomorphic head phantom were within ±5% of the TPS dose values. The use of a lead shield placed in the phantom’s eye socket reduced the dose to the eye lens by up to 20%.ConclusionsThe developed TLD dosimetry method provides a precise and reliable approach for in-vivo dose verification in skin surface brachytherapy. By integrating calibrated TLD-based measurements, the correct implementation of radiotherapy plans can be verified. The study also confirms the protective efficacy of an eye shield in minimizing radiation exposure to the lens, reinforcing the importance of shielding strategies in clinical practice. Further validation and clinical implementation will contribute to improved patient safety and therapeutic outcomes in brachytherapy.

Average glandular doses in contrast-enhanced spectral mammography (CEM)

Mon, 01 Dec 2025 00:00:00 GMT

IntroductionContrast-enhanced spectral mammography (CEM) is based on dual-energy breast exposure following intravenous administration of an iodinated contrast agent. Our study quantitatively assessed radiation dose from CEM for different breast thicknesses and compared it with doses from full-field digital mammography (FFDM) and with the dose limits set in the European Guidelines.Materials and MethodsWe studied 200,976 exposures from 59,438 examinations performed between January 2019 and December 2023 at the National Research Institute of Oncology, using a GE Healthcare Pristina Senographe mammography unit. Radiation exposure–related data, including average glandular dose (AGD) values, were obtained from the GE DoseWatch monitoring system. Doses for CEM exposure pairs (low- and high-energy exposure) were summed.ResultsOut of 176,700 FFDM exposures, the acceptable dose level was exceeded only in 11 cases (less than 0.01%). For combined CEM exposures, the acceptable dose level was exceeded in 965 out of 5481 cases (17.6%).The doses in FFDM exposures and low-energy CEM exposures are similar. Average glandular dose for FFDM exposures and low-energy CEM exposures is clearly dependent on the breast thickness. In contrast, the dose for a single high-energy CEM exposure is about 0.7 mGy and shows no clear dependency on breast thickness.Acceptable dose levels for combined CEM exposures were exceeded primarily with breasts with small thicknesses, most often (70% of cases) in patients whose breasts were less than 4 cm thick. For breasts from 6 cm and larger, no CEM exposures exceeded acceptable dose levels.ConclusionsAlthough CEM exposures are a combination of two exposures (low- and high-energy), in most cases, the doses associated with CEM exposure do not exceed limits that were originally set for single FFDM exposures.

Investigating the Dose Parameters of Low-Level Laser Therapy to Optimize Therapeutic Efficacy

Mon, 01 Dec 2025 00:00:00 GMT

IntroductionLow-level laser therapy (LLLT), also known as photobiomodulation, has emerged as a promising therapeutic option for various medical applications, including pain management and wound healing. This study aims to investigate the dose parameters of LLLT to optimize therapeutic efficacy.Materials and MethodsWe utilized Finite Element Analysis within the COMSOL Multiphysics software package to model light-tissue interactions and refine dosing protocols. Lasers with wavelengths of 660 nm, 780 nm, and 808 nm were selected due to their widespread use in therapy. Additionally, we examined several factors that impact the effectiveness of the treatment. Key parameters considered include energy, energy density, power, power density, irradiation time, and tissue penetration depth.ResultsThe recommended stimulation time should not exceed six minutes (480 seconds) at a power density of 15.62 mW/cm². However, if the power density is reduced to a maximum of 3.10 mW/cm2, the stimulation time can be safely extended to 10 minutes (600 seconds) without causing undesirable thermal effects, as long as the tissue temperature does not exceed 40°C during the extended stimulation.It is important to note that the dose applied to the surface of the tissue significantly decreases as it penetrates deeper. The average energy loss is approximately 11% per millimetre of tissue. Our simulations indicate that effective doses range from 0.38 J/cm² to 9.37 J/cm² while maintaining safe tissue temperatures, which are consistent with WALT recommendations.ConclusionOur findings help identify factors influencing stimulation, guiding therapists to standardize treatment parameters such as wavelength, exposure time, and dosages measured in joules, watts, W/cm², and J/cm² for consistency and safety across studies.

Letter to the Editor: Why continuing education matters for X-ray technicians

Mon, 01 Dec 2025 00:00:00 GMT