Image-guided radiotherapy supported by surface guidance can help to track lower lung lesions’ respiratory motion while reducing a patient’s exposure to ionizing radiation. However, it is not always ...clear how the skin’s respiratory motion magnitude and its correlation with the lung lesion’s respiratory motion vary between different skin regions of interest (ROI). Four-dimensional computed tomography (4DCT) images provide information on both the skin and lung respiratory motion and are routinely acquired for the purpose of treatment planning in our institution. An analysis of 4DCT images for 57 patients treated in our institution has been conducted to provide information on the respiratory motion magnitudes of nine skin ROIs of the torso, a tracking structure (TS) representing a lower lung lobe lesion, as well as the respiratory motion correlations between the nine ROIs and the TS. The effects of gender and the adipose tissue volume and distribution on these correlations and magnitudes have been analyzed. Significant differences between the ROIs in both the respiratory motion magnitudes and their correlations with the TS have been detected. An overall negative correlation between the ROI respiratory magnitudes and the adipose tissue has been detected for ROIs with rib cage support. A weak to moderate negative correlation between the adipose tissue volume and ROI-to-TS respiratory correlations has been detected for upper thorax ROIs. The respiratory magnitudes in regions without rib support tend to be larger for men than for women, but no differences in the ROI-to-TS correlation between sexes have been detected. The described findings should be considered when choosing skin surrogates for lower lung lesion motion management.
This study presents national surveys of patient exposure from nuclear medicine (NM) diagnostic procedures in 2010 and 2015 in the Republic of Croatia.
The survey was performed according to the ...European Commission Dose DataMed (DDM) project methodology. 28 most frequent NM diagnostic procedures were identified. Data about frequencies of procedures and average administered activities of radioisotopes used in those procedures were collected. Average administered activities were converted to effective doses according to the dose conversion coefficients. Then the collective effective dose to the population and an effective dose per capita were calculated based on the number of the most frequent NM diagnostic procedures and the average effective dose per procedure.
In 2010, 41200 NM diagnostic procedures led to 146.7 manSv collective effective dose to the population and in 2015, 42000 NM diagnostic procedures led to 146.8 manSv collective effective dose to the population. The frequencies of NM diagnostic procedures were 9.7 and 9.8 annually per 1000 population with 34.1 μSv and 34.2 μSv effective dose per capita for 2010 and 2015, respectively. The main contributors to the annual collective dose from NM in Croatia are examinations of the bone, heart, thyroid and PET/CT tumour diagnostic. Average administered activities have not changed considerably from 2010 to 2015. Nevertheless, within the frequency of some of the procedures, significant changes were found in five-year period.
Frequencies, average administered activities and collective effective dose to the population from NM diagnostic procedures in Croatia are comparable to the values reported by other European surveys. Changes were found between 2010 and 2015 and we intend to perform this study periodically to identify possible trends, but also to raise awareness about the potential dose optimization.
Glioblastoma (GBM) is the most aggressive glial tumor of the central nervous system. Despite intense scientific efforts, patients diagnosed with GBM and treated with the current standard of care have ...a median survival of only 15 months. Patients are initially treated by a neurosurgeon with the goal of maximal safe resection of the tumor. Obtaining tissue samples during surgery is indispensable for the diagnosis of GBM. Technological improvements, such as navigation systems and intraoperative monitoring, significantly advanced the possibility of safe gross tumor resection. Usually within six weeks after the surgery, concomitant radiotherapy and chemotherapy with temozolomide are initiated. However, current radiotherapy regimens are based on population-level studies and could also be improved. Implementing artificial intelligence in radiotherapy planning might be used to individualize treatment plans. Furthermore, detailed genetic and molecular markers of the tumor could provide patient-tailored immunochemotherapy. In this article, we review current standard of care and possibilities of personalizing these treatments. Additionally, we discuss novel individualized therapeutic options with encouraging results. Due to inherent heterogeneity of GBM, applying patient-tailored treatment could significantly prolong survival of these patients.
At present, high energy electron linear accelerators (LINACs) producing photons with energies higher than 10 MeV have a wide use in radiotherapy (RT). However, in these beams fast neutrons could be ...generated, which results in undesired contamination of the therapeutic beams. These neutrons affect the shielding requirements in RT rooms and also increase the out-of-field radiation dose to patients. The neutron flux becomes even more important when high numbers of monitor units are used, as in the intensity modulated radiotherapy. Herein, to evaluate the exposure of patients and medical personnel, it is important to determine the full radiation field correctly. A model of the dual photon beam medical LINAC, Siemens ONCOR, used at the University Hospital Centre of Osijek was built using the MCNP611 code. We tuned the model according to measured photon percentage depth dose curves and profiles. Only 18 MV photon beams were modeled. The dependence of neutron dose equivalent and energy spectrum on field size and off-axis distance in the patient plane was analyzed. The neutron source strength (Q) defined as a number of neutrons coming from the head of the treatment unit per x-ray dose (Gy) delivered at the isocenter was calculated and found to be 1.12 × 1012 neutrons per photon Gy at isocenter. The simulation showed that the neutron flux increases with increasing field size but field size has almost no effect on the shape of neutron dose profiles. The calculated neutron dose equivalent of different field sizes was between 1 and 3 mSv per photon Gy at isocenter. The mean energy changed from 0.21 MeV to 0.63 MeV with collimator opening from 0 × 0 cm2 to 40 × 40 cm2. At the 50 cm off-axis the change was less pronounced. According to the results, it is reasonable to conclude that the neutron dose equivalent to the patient is proportional to the photon beam-on time as suggested before. Since the beam-on time is much higher when advanced radiotherapy techniques are used to fulfill high conformity demands, this makes the neutron flux determination even more important. We also showed that the neutron energy in the patient plane significantly changes with field size. This can introduce significant uncertainty in dosimetry of neutrons due to strong dependence of the neutron detector response on the neutron energy in the interval 0.1–5 MeV.
•A model of medical linear accelerator (Siemens ONCOR) was built using the MCNP611 code.•Neutron dose equivalent and energy spectrum in the patient plane was analyzed.•Neutron flux increases with field size.•Field size has almost no effect on the shape of neutron dose profiles.•The mean energy of the neutrons increases with collimator opening at isocenter.
Magnetic resonance imaging is recognized as a useful modality in breast imaging. Motion is considered the most relevant cause of artefacts in breast MRI leading to degraded image quality or rendering ...studies non-diagnostic. The important reason for patient motion is contrast administration. Contrast administration may lead to discomfort, feeling of tingling and warmth, and pain in the arm contrast was administered to. The aim of our study was to determine the influence of contrast agent injection side and improve communication with patients on motion artifacts on subtraction reconstructions in order to prove that unexpected events may cause non-physiological movement resulting in motion artifacts, and that well-timed warning may decrease such artifacts. 146 patients with breast MRI from July 2019 to May 2020 were included. 71 of them were warned before the dynamic sequence started, and 75 of them didn't receive any warning for contrast application. The pectoral shift, in millimeters in the anteroposterior and lateral-lateral directions, was measured. Pectoral shift showed to be larger in unwarned patients when compared to warned ones with high significance (p=0.001) -no artifacts were observed in 361 warned, and 267 in unwarned women. Furthermore, artifacts were significantly larger on the side contralateral to contrast administration (median value of 2mm for the same side, and 1mm on the opposite side). In conclusion, our study showed that if patients knew the exact time of contrast application, the motion artifacts would be less pronounced; and that we should apply the contrast agent on the side opposite to the breast pathology is expected in.
Breast carcinoma is the most common neoplasm in the female population of Croatia. The main imaging breast diagnostic modalities are mammography, ultrasound, and magnetic resonance. This paper reviews ...radiological guidelines for breast diagnostic and interventional procedures, and monitoring of breast cancer patients in the Republic of Croatia. An algorithm for radiological assessment is presented for symptomatic patients, pregnant and lactating women, patients with average and increased risk of developing breast cancer, and patients with radiological findings of mastitis.
Rak dojke najčešća je zloćudna novotvorina u žena u Republici Hrvatskoj. Osnovne radiološke pretrage u dijagnostici bolesti dojke jesu mamografija, ultrazvuk i magnetska rezonancija. U radu su ...prikazane radiološke smjernice za radiološku dijagnostičku i intervencijsku obradu bolesti dojke i praćenje bolesnica oboljelih od raka dojke u Republici Hrvatskoj. Razrađen je algoritam radiološke obrade kod simptomatskih bolesnica, trudnica i dojilja, bolesnica prosječnog i povećanog rizika za razvoj karcinoma dojke, te kod bolesnica s radiološkim nalazom upalnih promjena (mastitisa).
Abstract Purpose The study was aimed to provide objective evidence about the mammographic image quality in Croatia, to compare it between different types of MG facilities and to identify the most ...common deficiencies and possible reasons as well as the steps needed to improve image quality. Materials and methods A total of 420 mammographic examinations collected from 84 mammographic units participating in the Croatian nationwide breast cancer screening program were reviewed in terms of four image quality categories: identification of patient and examination, breast positioning and compression, exposure and contrast, and artifacts. Those were rated using image evaluating system based on American College of Radiology and European Commission proposals. The results were compared among different types of mammographic units, and common image quality deficiencies were identified. Results Total image quality scores of 12.8, 16.1, 13.0 and 13.7 were found for general hospitals, university hospitals, private clinics and public healthcare centres, respectively. Average score for all mammographic units was 13.5 (out of 25 points). University hospitals were significantly better than all other mammography units in overall image quality, which was mostly contributed by better breast positioning practices. Private clinics showed the worst results in identification, exposure, contrast and artifacts. Conclusions Serious deficiencies in identification and breast positioning, which might compromise breast cancer screening outcome, were detected in our material. They occur mainly due to subjective reasons and could be corrected through additional staff training and improvement of working discipline.
A national audit of mammography equipment performance, image quality and dose has been conducted in Croatia. Film-processing parameters, optical density (OD), average glandular dose (AGD) to the ...standard breast, viewing conditions and image quality were examined using TOR(MAM) test object. Average film gradient ranged from 2.6 to 3.7, with a mean of 3.1. Tube voltage used for imaging of the standard 45 mm polymethylmethacrylate phantom ranged from 24 to 34 kV, and OD ranged from 0.75 to 1.94 with a mean of 1.26. AGD to the standard breast ranged from 0.4 to 2.3 mGy with a mean of 1.1 mGy. Besides clinical conditions, the authors have imaged the standard phantom in the referent conditions with 28 kV and OD as close as possible to 1.5. Then, AGD ranged from 0.5 to 2.6 mGy with a mean of 1.3 mGy. Image viewing conditions were generally unsatisfying with ambient light up to 500 lx and most of the viewing boxes with luminance between 1000 and 2000 cd per m2. TOR(MAM) scoring of images taken in clinical and referent conditions was done by local radiologists in local image viewing conditions and by the referent radiologist in good image viewing conditions. Importance of OD and image viewing conditions for diagnostic information were analysed. The survey showed that the main problem in Croatia is the lack of written quality assurance/quality control (QA/QC) procedures. Consequently, equipment performance, image quality and dose are unstable and activities to improve image quality or to reduce the dose are not evidence-based. This survey also had an educational purpose, introducing in Croatia the QC based on European Commission Guidelines.
The aim of this study was to evaluate whether the combination of B-mode ultrasound, elastography score (ES) and strain ratio (SR) improves diagnostic performance with respect to breast lesions. One ...hundred thirty lesions were prospectively evaluated by B-mode ultrasound and strain elastography, followed by fine-needle aspiration cytology/biopsy in 117 woman who were scheduled for regular breast BUS. The median ES (4.5 vs. 2.9, p < 0.001) and SR (4.9 vs. 2.3, p < 0.001) were significantly higher for malignant than for benign lesions. A sensitivity of 90.5% and specificity of 93.2% for the ES (cutoff point = 3.8) and a sensitivity of 87.5% and specificity of 87.6% for the SR (cutoff point = 3.5) were obtained. Elastography combined with B-mode ultrasound improved the specificity, accuracy and positive predictive value. Receiver operating characteristic curves yielded a higher value for the combined technique for diagnosis of breast lesions. Routine use of such a diagnostic algorithm could reduce the number of unnecessary biopsies.
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