Meilutytė-Lukauskienė, Diana

Introduction. Radiotherapy (RT) for head and neck cancer (HNC) is associated with acute neu- rotoxic and functional sequelae affecting peripheral nerves, mucosal sensory pathways, speech, and swallowing mechanisms. Many of these symptoms remain under-recognised in oncological practice. Patient-reported outcome measures (PROMs) enable systematic identification of early neurological and functional impairments that emerge during treatment. Methods. A prospective observational study was conducted at the Lithuanian University of Health Sciences Oncology Hospital. Adult HNC patients undergoing active RT completed the EORTC QLQ-C30 and the head and neck–specific module (QLQ-H&N35). Clinically relevant symptom burden was defined as Likert-scale responses of 3 or higher. Descriptive statistics were used to determine the prevalence of functional, neurological, and psychological impairments. Results. Interim analysis included 20 patients (15% female, 85% male). The mean age was 60.5 ± 3.4 years for females and 64.8 ± 7.3 years for males. Clinically relevant emotional dys- function was reported by 41% of patients, and physical impairment by 40%. The most prevalent systemic symptoms were insomnia (60%), pain (57.5%), and fatigue (51.7%). Neurologically ori- ented impairments were frequent: chewing difficulties (55%), sticky saliva (50%), neuropathic pain (46.3%), speech disturbances (46%), coughing (45%), and xerostomia (45%). Sensory dis- turbances were less common (20%). Females tended to report a higher symptom burden across several domains, although the sample size was limited. Conclusions. Active radiotherapy for head and neck cancer is associated with a substantial early neurological and functional symptom burden. Structured integration of patient-reported outcome measures may enhance detection of treatment-related neurofunctional toxicity and support proactive multidisciplinary management within radiotherapy workflows.

Collagenous colitis (CC) is diagnosed histologically and is characterised by a thickened subepithelial collagen band together with inflammatory and epithelial changes. Although routine haematoxylin and eosin (H&E) staining is sufficient for diagnosis in most cases, visual assessment of the collagen band can be challenging in borderline or heterogeneous specimens. Additional stains may be required in diagnostically difficult situations.

The Killip classification is a long-established bedside tool for early haemodynamic risk stratification in ST-elevation myocardial infarction (STEMI). However, its prognostic performance in contemporary STEMI populations treated with primary percutaneous coronary intervention (PCI) remains debated. We aimed to re-evaluate the association between Killip class and in-hospital mortality in a modern STEMI cohort.

Image-guided radiotherapy (IGRT) has enhanced the precision of cancer treatment by integrating imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) into daily radiotherapy workflows. In head and neck cancer, where anatomical changes are common, accurate image registration between planning and treatment scans is essential to ensure dose accuracy. However, geometric distortions in CBCT (such as translation, rotation, and scaling resulting from patient positioning variations observed in daily CBCT images) can affect tumour targeting and dose delivery. This pilot study assesses a MATLAB-based image correction algorithm that uses rigid bony landmarks and point cloud registration together with spatial transformation to align CBCT with planning CT. Two head and neck cancer patients were retrospectively analysed, selected for their contrasting anatomical responses: one with substantial tumour regression and one with minimal change. Imaging was performed on the Halcyon V3.1 linear accelerator (Varian Medical Systems), with 25 daily CBCT scans per patient (85–96 slices per scan), resulting in 50 datasets for analysis. Spatial deviations were measured along the X, Y, and Z axes, and dose recalculations were performed for each treatment fraction. The correction method significantly improved spatial congruence and reduced geometric discrepancies caused by voxel spacing and acquisition parameters. Uncorrected scans showed dose deviations of up to ± 12% in organs at risk, notably the spinal cord and parotid glands. These findings demonstrate the feasibility and dosimetric relevance of automated CBCT correction in daily head and neck radiotherapy. Although limited in sample size, the study provides a detailed technical and dosimetric analysis of spatial distortions and supports future validation in larger patient cohorts.

Patient positioning, together with physical changes in soft tissues during the course of radiotherapy, significantly affects the irradiation of targeted tissues and adjacent structures. This leads to a high risk of under-dosage of the tumour and/or over-dosage of critical normal structures during the late sessions of treatment. Accurate and timely identification of irradiation-affected tissue regions is highly valuable for adaptive radiotherapy planning. We propose a method for the identification and evaluation of specific computed tomography (CT) attenuation changes that can reveal the affected tissue regions. The search for correlated CT attenuation changes in the tumour and surrounding tissues, based on principal component analysis of series of intensity values in each fixed voxel, can reveal the actual three-dimensional region of irradiation-affected tissues for radiotherapy control and replanning.

Ensuring selective irradiation of target tissues is one of the biggest challenges in radiotherapy. Methods and devices of Image-Guided Radiotherapy (IGRT) are elaborated with the aim of ensuring that the prescribed radiation dose is delivered accurately to the tumour while minimising exposure to surrounding healthy tissues. Technical solutions ensure a few-millimetre, or even sub-millimetre precision of the irradiation beam, while with currently used mechanical means of patient positioning, we can expect much bigger positioning deviations, reaching even centimetre range. Patient positioning deviation to a certain extent is related to changes in soft tissue density and volume, which change during the period of treatment. Therefore, the discovery of reliable reference structures in routinely performed daily Cone-Beam Computed Tomograms (CBCT) was one of the aims of this study. Having the reliable reference structures, we carried out the retrospective estimation of patient position deviation during the whole treatment cycle and evaluated possible dynamics of unwanted irradiation of tumour-surrounding critical organs. The study was conducted in patients with head and neck cancer treated in the Lithuanian University of Health Sciences Kaunas Clinics Affiliated Hospital of Oncology, Department of Radiotherapy. Patients’ positioning was evaluated using volumetric images obtained by the CBCT machine integrated into the Halcyon V3.1 linear accelerator (Varian Medical Systems, Palo Alto, CA, USA). Custom-made algorithms of hard tissue segmentation and actual patient position estimation were elaborated in MATLAB (MathWorks, USA) environment. The hard tissue structures in volumetric images, in particular the mandible and part of the skull, were segmented and adjusted using mathematical morphology algorithms. We found these structures as reliable reference landmarks for patient position estimation. We found the deviation of actual patient position ranging from 1 to 3,5 mm, which resulted in changes in irradiation ranging from 0,016 to 0,057 Gy/fraction in the planned target volume and in critical surrounding organs (e.g. larynx, parotid, etc.) as well. The values indicate that it can cause significant damage to the surrounding organs. In conclusion, we state that specially selected hard tissue structures can serve as reliable landmarks of patient position, while soft tissues eventually change. The development of more precise image-guided radiotherapy methods can significantly reduce the damage to tumour-surrounding organs.

Maximisation of irradiation accuracy of malignant tissues is a key challenge on the way to optimal radiotherapy. Strategies to improve irradiation accuracy should balance the expected clinical benefit against the feasibility and procedural demands of the method used. This pilot study marks an initial step toward retrospectively evaluating patient positioning accuracy, analysing CBCT images in relation to clinical outcomes, and estimating actual irradiation of target and surrounding tissues. The CBCT images were acquired from head and neck patients treated with the Halcyon V3.1 linear accelerator. The algorithms for precise alignment of images, which made it possible to estimate the detailed changes in tumour tissue density during treatment sessions were developed in the MATLAB. The recalculation of the actual dose showed that even small positioning errors can lead to significant changes in the delivered dose, especially in areas where critical organs are affected.

Vaizdais valdoma radioterapija (angl. image-guided radiotherapy) padidino gydymo tikslumą, tačiau naviko atsakas dažniausiai vertinamas tik gydymo pabaigoje. Nors kasdien atliekami kūginio pluošto kompiuterinės tomografijos tomografijos – KPKT (angl. cone beam computed tomography) vaizdai yra įprasti verifikacijai, jie retai naudojami išsamesnei analizei ar gydymo efektyvumo įvertinimui. Tai ypač svarbu galvos ir kaklo navikų atvejais, kur dažni naviko tūrio, paciento svorio ir organų padėties pokyčiai tarp frakcijų gali būti kliniškai reikšmingi [1, 2]. Nepaisant termoplastinių kaukių ir kitų imobilizavimo priemonių, pacientų padėties nuokrypiai išlieka. Be to, KPKT ir planavimo KT vaizdų registracija dažnai apsunkinama dėl skirtingų skenavimo sąlygų - pjūvių neatitikimo, poslinkių, pasukimų ar mastelio iškraipymų. Nors šie neatitikimai dažnai sunkiai pastebimi kasdienėje praktikoje, jie gali reikšmingai paveikti suplanuotą dozę, ypač esant stipriam atsakui į gydymą. Šio tyrimo tikslas – įvertinti vaizdų neatitikimų įtaką dozės nuokrypiams nuo suplanuotosios dozės, skirtingo atsako į spindulinę terapiją kontekste. Tyrimo metu buvo analizuoti LSMUL KK Onkologijos ligoninėje, linijiniu greitintuvu Halcyon V3.1 gydytų dviejų pacientų, sergančių galvos-kaklo navikais, kiekvienos procedūros metu registruoti KPKT vaizdai. Siekiant koreguoti erdvinius iškraipymus KPKT vaizduose, buvo identifikuoti kauliniai orientyrai pagal jų Hounsfieldo vieneto (HU) reikšmes ir suformuoti trimačiai taškų debesys. Duomenų registracijai naudotas MATLAB aplinkoje sukurtas algoritmas, apimantis šiuos etapus: 1) retai išdėstytų taškų debesies generavimą; 2) iteracinio artimiausio taško atitikimo algoritmo taikymą; 3) erdvinės transformacijos įgyvendinimą, pritaikant transformacijos matricą KPKT duomenims. Pakoreguoti KPKT vaizdai buvo lyginami su planavimo KT vaizdais, siekiant įvertinti anatominį atitikimą. Pacientui, kuriam stebėtas silpnesnis atsakas į spindulinį gydymą, koordinačių nuokrypių vidurkis (standartinis nuokrypis) buvo: X (šonine kryptimi) – 2,51 (1,49) mm, Y (aukščio kryptimi) – 2,13 (1,31) mm, Z (išilgine kryptimi) – 1,92 (1,22) mm. Tuo tarpu pacientui su stipriu atsaku į gydymą, vidutiniai nuokrypiai buvo žymiai mažesni: X – 0,17 (0,13) mm, Y – 0,14 (0,12) mm, Z – 0,79 (0,99) mm. Remiantis šiais duomenimis, apskaičiuota dozės neatitiktis (procentais) suplanuotai dozei (1 lentelė). Kritinių organų - seilių liaukų, stemplės, stuburo smegenų - dozių neatitikimai kai kuriais atvejais viršija 3 %., t.y. peržengė leistinas radioterapijos ribas. Tyrimas parodė, jog net minimalūs pacientų padėties pokyčiai gali turėti kliniškai reikšmingų pokyčių apšvitos dozi. Rezultatai išryškino poreikį detalesnei vaizdų analizei bei KPKT duomenų integravimui, ypač svarstant adaptyvios terapijos galimybes.

Welcome to the captivating realm where the principles of physics intersect with the intricacies of medicine, providing deep insights into the workings of the human body and revolutionizing diagnostics and therapeutic approaches. This interdisciplinary journey will take you on a multi-faceted voyage of discovery, from the fundamental mechanics of bodily functions to the intricate interplay of light and matter and the profound effects of ionizing radiation in healthcare. At the center of this convergence is the application of fundamental physical concepts to decipher the complex relationships of human physiology. From the mechanics of body movement and function - exploring phenomena such as vibrations, sound waves and the propagation of acoustic signals - to eluci¬dating the molecular interactions and behavior of fluids in the human system, this journey reveals the underlying physical principles that govern not only a marvel of biological engineering but also a realm governed by the immutable laws of physics. As we venture further into the field of optics, we encounter a variety of phenomena ranging from the propagation of light waves to the intricate mechanisms of vision. The study of optics in medicine encompasses a variety of topics, including the nature of light, the principles of refraction and dispersion, the mechanisms of visual perception, and the construction and function of optical instruments such as lenses, microscopes, refractometers and polarimeters. By unravelling the mysteries of the interactions between light and matter, physicists and physicians alike are gaining invaluable insights into the diagnosis and treatment of various eye diseases, paving the way for better patient care and improved clinical outcomes. This book also covers the field of ionizing radiation - a powerful tool of modern medicine with profound implications for diagnosis and treatment. From the discovery of X-rays by Wilhelm Com-ad Roentgen to the ground-breaking advances in radiation oncology, the use of ionizing radiation has revolutionized medical imaging, cancer treatment and many other areas of healthcare. By elucidating the mechanisms of interaction between radiation and matter and quantifying the dosimetric properties of different radiation sources, physicists and radiation oncologists play a crucial role in optimizing treatment protocols, minimizing radiation exposure and ensuring the safety and efficacy of clinical interventions. Recognizing the diverse backgrounds and interests of our readership, this comprehensive learning resource has been carefully crafted to appeal to stu-dents from a broad spectrum of the health sciences. Whether you are a bud-ding physician, a curious biologist or a budding medical physicist, this book will serve as an introduction to the fascinating intersection of physics and medicine. Through a successful blend of theoretical foundations, practical applications, and hands-on laboratory exercises, students will not only be able to understand the intricate nuances of physics in healthcare but also to apply this knowledge in a variety of clinical and research situations.

Dichloro-difenil-trichloroetanas (DDT), aldrinas, endosulfanas priskiriami chloro organiniams pesticidams (COP), kurie buvo plačiai naudojami žemės ūkyje kenkėjams naikinti. COP aplinkoje gali išlikti nepakitę ilgą laiką (pvz., DDT skilimo pusperiodis trunka apie 36 metus). Tokiu būdu grunte ar požeminiame vandenyje susikaupę didesni pesticidų kiekiai tampa tos terpės teršalais, trikdančiais ekosistemų veiklas ir galinčiais sukelti kancerogeninį poveikį ar reprodukcinius sutrikimus paukščiams, žmonėms ir kitiems žinduoliams. Nors šių patvarių organinių junginių gamyba ir naudojimas buvo nutraukti arba bent jau apriboti 2001 m. pasirašius Jungtinių Tautų Stokholmo konvenciją, tačiau jų sukeltos taršos židiniai (pvz., COP liekanos grunte) egzistuoja iki šiol. Siekiant panaikinti COP liekanas grunte, ieškoma tinkamiausių šių pavojingų teršalų išvalymo metodų. Eksperimentinio tyrimo tikslas – ištirti terminės oro plazmos ir terminės vandens garo plazmos tinkamumą chloro organiniais pesticidais (daugiausia DDT 1569 μg/kg) užterštam gruntui valyti. Gruntas buvo tiriamas prieš ir po valymo su termine plazma naudojant skenuojantį elektroninį mikroskopą (SEM), optinį mikroskopą, fotokamerą, rentgeno spindulių energijos spektroskopą (EDS) ir dujų chromatografą- masių spektrometrą (GC-MS). Su SEM gauti rezultatai parodė, kad sąveikos metu tarp užteršto grunto ir terminės oro plazmos, taip pat terminės vandens garo plazmos vyko grunto struktūriniai pokyčiai. EDS matavimai atskleidė, kad termine plazma išvalytame grunte nebuvo aptikta chloro. Matavimai, atlikti su GC-MS, patvirtino, kad chloro organinių pesticidų koncentracijos grunte po grunto valymo su termine plazma sumažėjo iki minimalių verčių (<3,0–5,0 μg/kg). [...].