Introduction: This study evaluated the accuracy of various cone-beam computed tomography (CBCT) reconstruction modalities, specifically the HyperSight (HS) detector, in comparison to standard computed tomography (CT) simulation for potential use in online adaptive radiotherapy. The research focused on the Hounsfield Unit (HU) to relative electron density (RED) conversion and its subsequent impact on volumetric modulated arc therapy (VMAT) dose calculations. Methods: Two tissue-equivalent phantoms, the advanced electron density and the CIRS Thorax phantom, were utilized. Imaging was performed on a SOMATOM go.Open Pro CT simulator and a Varian TrueBeam medical linear accelerator using CBCT, HS-CBCT, HS-iterative CBCT (iCBCT) and HS-iCBCT metal artifact reduction protocols. Calibration curves (HU-RED) were generated for two regions: RED <1.2 and 1.2≤ RED <1.8. VMAT plans (6 MV) were created in the Eclipse 18.1 treatment planning system (TPS), using an anisotropic analytical algorithm (AAA) and Acuros XB algorithm. Absolute dose measurements were conducted using an SNC125c ionization chamber and compared with TPS-calculated doses. Results: In the soft-tissue region (RED <1.2), all imaging modalities showed an excellent linear correlation with CT (r > 0.998), with HU deviations within ± 30 HU. In the high-density region (1.2 ≤ RED < 1.8), HS-CBCT demonstrated superior stability with the lowest root mean square error, 62.88 HU. Dosimetric results showed that 96.7% of all measurement points met the ± 3–4% agreement criteria. For the AAA algorithm, HS-iCBCT exhibited the highest precision (standard deviation = 0.59) and the lowest mean absolute error. The Friedman test confirmed a statistically significant difference between modalities (p < 0.05), with HS-iCBCT showing the most consistent performance. Conclusion: Both HS-CBCT and HS-iCBCT provide highly accurate HU-RED conversions and reliable dosimetric results for RED < 1.8.

Various factors can affect the survival of patients with oropharyngeal cancer. We assessed the expression of protein p16INK4a, Flotillin2, epidermal growth factor receptor, and other clinicopathological features and their prognostic value for this type of cancer. We gathered patient data on demographics, clinicopathological characteristics, treatment patterns, and outcomes. Histologically and by immunochemistry staining we determined expression of prognostic factors and molecular biomarkers. The primary endpoints were overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS). Survival was assessed using the Kaplan–Meier method and Cox regression model analyses of potential prognostic parameters. After a median follow-up of 78 months, the median OS was 41 months, with an event recorded in 77.8% of patients. Median DFS was 22 months, 37 patients (51.4%) had disease relapse. The DSS survival rate was 58.3% with a median survival of 68 months. In regards to molecular biomarkers previously mentioned, there was no statistical significance for survival categories. After conducting a multivariate analysis of significant variables, we found that only recurrence, vascular invasion, and surgical intervention remained as factors with independent effects on both OS and DFS. Recurrence and the N stage were identified as independent prognostic factors for DSS. Our analysis underscores the complexity of factors that collectively influence survival following the diagnosis of OPSCC. Several factors were found to be statistically significant. These factors included the type of surgical procedure, disease relapse, vascular invasion, lymphatic invasion, perineural invasion, advanced T stage of the disease, N stage of the disease, and smoking status. The significance of these factors may vary across different types of survival. This analysis did not find any significant impact on survival from the growth factors tested, namely epidermal growth factor receptor, Flotillin2, and p16INK4a, in the applied regression models.

AIMS Interstitial high-dose-rate brachytherapy (HDR-BT) is an effective therapy modality for patients with localized prostate carcinoma. The objectives of the study were to optimise the therapy regime variables using two models: response surface methodology (RSM) and artificial neural network (ANN). MATERIALS AND METHODS Thirty-one studies with 5651 patients were included (2078 patients presented as low-risk, 3077 patients with intermediate-risk, and 496 patients with high-risk). A comparison of these therapy schedules was carried out using an effective biologically effective dose (BEDef) that was calculated assuming the number of treatment days and dose (D) per day. The modelling and optimization of therapy parameters (BEDef and risk level) in order to obtain the maximum biochemical free survival (BFS) were carried out by the RSM and ANN models. RESULTS An optimal treatment schedule (BFS = 97%) for patients presented with low-risk biochemical recurrence would be D = 26 Gy applied in one application, 2 fractions at least 6 h apart, within an overall treatment time of 1 day (BEDef = 251 Gy) by the RSM and ANN model. For patients presented with intermediate- or high-risk an optimal treatment regime (BFS = 94% and 90%, respectively) would be D = 38 Gy applied in one application, 4 fractions at least 6 h apart, with an overall treatment time of 2 days (BEDef = 279 Gy) by the RSM and ANN models. CONCLUSIONS The RSM and ANN models determine almost the same optimal values for the set of predicted therapy parameters that make a feasible selection of an optimal treatment regime.

Background: Various factors can affect the survival of patients with laryngeal cancer (LC). In this retrospective study, we assessed clinicopathological features, their prognostic value, and treatment modalities for patients with confirmed squamous cell LC. Methods: We collected patient data on demographics, clinicopathological characteristics, treatment patterns, and outcomes. The primary endpoints were overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and locoregional control (LRC). We assessed survival using the Kaplan–Meier method and Cox regression model analyses of potential prognostic parameters. Results: After a median follow-up of 76 months, 28 (33.3%) patients had a recurrence. The median OS was 78 months, with an event recorded in 50% of patients. The DSS median was not reached (NR) with a survival rate of 72.6%, the DFS survival rate was 66.7% with median NR, and the LRC survival rate was 72.6% with median NR. After conducting a multivariate analysis of significant variables, we found that only recurrence and lymphatic invasion had an independent effect on OS and recurrence in DSS, while subsite impacted DFS and LRC. Conclusions: Survival trends were consistent with other studies, except for OS. Recurrence, lymphatic invasion, and subsite location were significant factors that impacted patient survival.

Background / Aim: Hidradenitis suppurativa (HS) is a chronic inflammatory disease that most often affects apocrine gland-bearing areas of the skin. The treatment depends on the severity of the clinical presentation. The paper objective was to present new modalities in management and treatment of HS. Methods: The subjects in this research included the patients suffering from the severe form of HS, who were treated in the University Clinical Centre of the Republic of Srpska for the past three years. The effect of treatment of HS were monitored. In four patients, biologic therapy with adalimumab or adalimumab biosimilars was administered, while four patients received radiotherapy and 17 of them, were treated surgically. Depending on the type of treatment, the effects of therapy were monitored after 6-12 weeks by using clinical examination and by assessing the disease stage according to the Hurley staging. Due to a small number of subjects, especially in patients treated with biologic and radiotherapy, it was not possible to perform any statistical analysis and the results were presented by description, in tables and photographs. Results: Biologic therapy: Adalimumab was administered subcutaneously 80 mg, twice a month. After 12 weeks, in 4 patients was observed a regression of changes by 60-70 % when compared to previous skin changes. Radiotherapy: the total radiation dose was 5 Gy, distributed in 5 or 10 fractions. After 12 weeks an improvement by 60-70 % was observed. Surgical treatment: after 6-8 weeks, the patients were fully recovered. Conclusions: Application of biologic and radiotherapy after 12 weeks had similar results, ie it brought to regression of changes by 60-70 %. The best results were achieved after surgical treatment of HS.

Based on the computed tomography (CT) images it is not possible to see all the lymph nodes that belong to the stomach. In radiotherapy, for a clinical target volume (CTV) delineation based on CT images, it is necessary to determine the appropriate margin around the corresponding blood vessels to make sure that all the required lymph nodes will be irradiated. The larger margin will certainly cover all the lymph nodes but it can also produce an increase of the received dose in the normal tissues. While a smaller margin can eventually spare the normal structures as a consequence it brings a higher risk of missing the suspected lymph nodes. The aim of this study was to analyse the radiation doses received by some organs at risk (OARs) in the case of the three-dimensional conformal radiotherapy (3DCRT) treatment of the gastric cancer, for lymph node CTV margin sizes 5 mm, 7 mm and 10 mm. The study included 40 patients undergo the external beam radiotherapy (EBRT) treatment of gastric cancer. The one-way analysis of variance (ANOVA) with repeated measures test and Friedman’s nonparametric test have been used for testing the statistical significance of differences among the examined groups. The difference between the examined groups has been considered significant if p < 0.05. The statistically significant differences in the dose contributions to the observed OARs (spinal cord, heart, small bowel and colon), among the examined CTVs, were found.

Cilj. Uporediti dozimetrijske parametre trodimenzionalne konformalne radioterapije (3DCRT) i volumetrijski modulirane lučne radioterapije (VMAT-RA) kod postoperativnog tretmana glioblastoma (GBM). Metode: Retrospektivno istraživanje uključilo je pacijente s dijagnozom GBM, liječene u periodu od septembra 2014. do januara 2017. u Centru za radioterapiju Banja Luka. Za svakog pacijenta pojedinačno urađena je simulacija kompjuteriziranom tomografijom (CT) i registracija postoperativne magnetne rezonance (MRI). Delineacija ciljnog volumena (PTV) i organa od rizika (OAR) urađena je prema registriranom MRI i ESTRO-ACROP preporukama. Tretman je proveden 3DCRT radioterapijom konkomitantno uz temozolomid. Naknadno je za svakog pacijenta urađen VMAT-RA plan s optimizacionim parametrima koji zadovoljavaju dozne limite OAR. Dodatne optimizacije nisu rađene, jer pacijenti nisu planirani da se zrače VMAT tehnikom. Kontrolnu grupu činili su 3DCRT planovi, a VMAT-RA eksperimentalnu grupu. Propisana je doza TD 54 – 60 Gy. Za obje tehnike zračenja su komparirani dozimetrijski parametri u dozno-volumnom histogramu (DVH). Shapiro-Wilk-ov test pokazao je asimetričnu distribuciju, značajnost razlika je utvrđena Wilcoxonovim testom predznaka rangova. Sve p vrijednosti manje od 0.05 smatrane su statistički značajnim. Rezultati: Pokrivenost dozom 98%, 95%, 50% i 2% volumena PTV tehnikom 3DCRT iznosila je 95.36±1.08, 96.88±0.88, 100.74±1.08 i 104.76±1.34, a za RA 96.53±0.86, 97.63±0.65, 100.05±0.15 i 102.47±0.55 redom, statistička značajnost p=0.007, 0.022, n.s i 0.005. Indeks homogenosti (HI) za 3DCRT je 0.09±0.02, za RA 0.06±0.01, p=0.005. Indeks konformalnosti (CI) za 3DCRT je 0.98±0.01, za RA 0,98±0,02, p=n.s. Doza na moždano stablo, ipsilateralni i kontralteralni optički nerv i hijazmu bila je nešto veća za RA, ali bez statističke značajnosti. Volumen mozga V50 bio je značajno manji kod RA. Zaključak: Primjena VMAT- RA tehnike bez dodatnih dozimetrijskih optimizacija u odnosu na 3DCRT rezultira boljom pokrivenosti PTV-a dozom i boljom homogenosti doze unutar PTV-a, ali bez značajne razlike u dozi koju primaju OAR.

Introduction: Using computed tomography (CT) and treatment planning systems (TPS) in radiotherapy, due to the difference in photon beam energy on CT and linear accelerator, it is necessary to convert Hounsfield units (HU) to relative electron density (RED) values. The aim of this dosimetric study was to determine whether there is a significant effect of potential in the CT tube, field of view size (FOV), and phantom dimensions on the CT conversion curve CT-RED. The second aim is whether there are significant differences between the CT-RED obtained by the Computerized Imaging Reference Systems (CIRS) Thorax 002LFC phantom and the “reference” curve in the TPS, obtained by the CIRS 062M pelvis phantom, at the same CT conditions.Methods: Heterogeneous CIRS 062M and CIRS Thorax 002LFC phantoms were used, which anatomically and dimensionally represent the human pelvis, head, and thorax, with a set of known RED inserts. They were scanned on a CT LightSpeed GE simulator and obtained CT-RED.Results: The high voltage in the CT tube had a significant effect on the HU (t = 10.72, p < 0.001) for RED values >1.1, while FOV as a parameter did not show statistical significance for the 062M pelvis phantom. Comparing the slopes (062M pelvis and head) of the CT-RED for RED ≥ 1.1, the obtained value is t = 1.404 (p = 0.163). In the case of a 062M pelvis and a 002LFC phantom, we have seen a difference in RED values (for the same HU value) of 5 % in the RED region ≥ 1.1 (bone).Conclusion: Patients should be imaged on a CT simulator only at the potential of the CT tube on which the conversion curve was recorded. The influence of the FOV and scanned phantom dimensions is not statistically significant on the appearance of the calibration curve (RED ≥ 1.1).

Introduction: Gated tangential field-in-field (FIF) technique is used to lower the dose to organs at risk for breast cancer radiotherapy (RT). In this study, the authors investigated the accuracy of the delivered treatment plan with and without gating using a two-dimensional detector array for patient-specific verification purposes.Methods: In this study, a 6MV beams were used for the merged FIF RT (forward Intensity Modulated Radiation Therapy). The respiration signals for gated FIF delivery were obtained from the one-dimensional moving phantom using the real-time position management (RPM) system (Varian Medical Systems, Palo Alto, CA). RPM system used for four-dimensional computed tomography scanner light-speed, GE is based on an infrared camera to detect motion of external 6-point marker. The beams were delivered using a Clinac iX (Varian Medical Systems, Palo Alto, CA) with the multileaf collimator Millennium 120. The MapCheck2 (SunNuclear, Florida) was used for the evaluation of treatment plans. MapCheck2 was validated through a comparison with measurements from a farmer-type ion chamber. Gated beams were delivered using a maximum dose rate with varying duty cycles and analyzed the MapCheck2 data to evaluate treatment plan delivery accuracy.Results: Results of the gamma passing rate for relative and absolute dose differences for all ungated and gated beams were between 95.1% and 100%.Conclusion: Gated FIF technique can deliver an accurate dose to a detector during gated breast cancer RT. There is no significance between gated and ungated patient-specific quality assurance (PSQA); one can use ungated PSQA for verification of treatment plan delivery