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Introduction: Parametric mapping is a non-invasive method to quantify tissue changes in the myocardium by measuring T1, T2 and T2* relaxation times and extracellular volume, requiring a pre-established range of normal values. Purpose: To establish reference values for native T1 and T2 myocardial relaxation times in healthy subjects on 1.5 T magnetic resonance imaging and to assess changes in their values according to left ventricular segments, age, sex, heart rate, and myocardial thickness. Material and Methods: A prospective 1.5 T magnetic resonance imaging study was performed with the voluntary participation of 50 healthy individuals in different age groups. Image analysis was performed by a radiologist with 5 years of experience in the field of CMRT and further coordinated with a radiologist with more than 20 years of expe-rience in the field. Siemens ARGUS integrated software was used to calculate the volumes and function of both cameras. Global and segmental T1 and T2 values were measured in the shortaxis midlevel section by manually delineating the region of interest. Myocardial thickness of the mid septum was measured for each patient. Results: The distribution of volunteers was 25 men and 25 women. Significantly higher global T1 values were observed in women (1027.7 ± 25.4 ms) compared to men (992.9 ± 24.4 ms), at p < 0.001. The same correlation was observed in individual segments, with a significant difference between genders. Examination of the correlation between T1 and other parameters demonstrated a negative linear relationship only with myocardial thickness. Global T2 in women (48.6 ± 2.49 ms) was also significantly higher than in men (44.6 ± 2.06 ms), with an observed difference of 3.95, p < 0.001. Global T2 showed a very strong negative correlation with myocardial thickness (r = -0.769; p < 0.001). There was no sig-nificant correlation between T2 times and heart rate and age of patients. Conclusion: A statistically significant difference in native T1 and T2 values by sex was demonstrated. The use of sex-specific reference values to distinguish healthy from pathologically affected myocardium is recommended.

In recent decades, cardiac magnetic resonance imaging (CMR) has been established as a valuable tool in the diagnosis of patients with or at risk of heart failure. With its ability to characterize tissue changes in the myocardium, CMR can provide detailed and clinically useful information about the type and severity of cardiac damage. The method is not only important for differentiation of ischemic from non-ischemic cardiomyopathy, but also contributes to the correct diagnosis of non-ischemic cardiomyopathy subtypes. It is also widely accepted as a reference standard for the quantification of myocardial mass, volumes and ejection fraction. The purpose of this article is to review the role of CMR in the diagnosis and treatment of non-ischemic cardiomyopathies.

Cardiac magnetic resonance tomography is widely used method in the diagnosis of cardiovascular diseases. In the last decade, new techniques have been developed to obtain quantitative parameters of myocardial changes. T1 and T2 mapping are part of the routine CMRT protocol and allow direct quantification of T1 and T2 relaxation times in the myocardium as well as the calculation of extracellular volume. These are important biomarkers both for the diagnosis of various myocardial diseases and for monitoring treatment follow-up and determining prognosis. The purpose of this article is to provide a brief overview of the basic principles of the T1 and T2 mapping techniques, as well as their main applications in different types of cardiomyopathies.

Cardiac magnetic resonance tomography (CMRT) is a method of high diagnostic value in the assessment of cardiac vitality through the application of various perfusion techniques, as well as in the evaluation and diagnosis of early myocardial ischemic changes. The aim of this article is to review the different technical aspects of CMRT. A major problem in CMRT studies is the deterioration of image quality due to the presence of motion artefacts. This necessitates the development of ECG-gated and respiratory triggered or breath-holding techniques and their implementation in practice. In contrast to most other applications of MRT, the planes used in CMRT are defined with respect to the orientation of the heart so that they are parallel and orthogonal to the cardiac axes. Two main groups of sequences are used in CMRT: 1) to determine morphology, function, and blood flow and 2) to provide good tissue contrast of the heart. Technological development of the method has not stopped, and techniques and pulse sequences continue to be developed to improve the diagnostic capabilities of CMRT. Through proper planning, a thorough understanding of the cardiac planes, and appropriate selection of technical parameters for the respective sequences depending on the clinical finding being addressed, a successful performance of each CMRT study is achieved.

Background: Radiation-induced injuries to patient skin as a result of fluoroscopy guided interventional procedures are infrequently reported, often misdiagnosed and there is a need to learn lessons from every injury. Methods: This paper describes two cases of radiation induced skin injuries that are, to the best of our knowledge, the first ever reported cases from Bulgaria and possibly from Eastern Europe, and would thus have educational value. Results: The important messages from the skin injuries reported here are: lack of awareness among part of the interventional specialists about the potential for radiation induced skin injury, misdiagnosis after injury happened because of lack of awareness and knowledge among general physicians, dermatologists and surgeons who followed up cases of skin injuries; the lack of system to monitor patients with relatively high exposure; the important role played by the medical physicist in diagnosing the injury and overall in initiating actions; the role of training and informational material displayed in interventional facilities. Conclusions: For avoidance of skin injuries from interventional procedures it is of utmost importance to implement a system that includes (a) regular monitoring of radiation dose parameters of the procedure; (b) established trigger values for reporting; (c) procedure for patient follow-up if a trigger value is exceeded; (d) instructing the patient who has received exposure above the trigger value to self-examine the irradiated area of the skin for any itching/redness and report it back. [ABSTRACT FROM AUTHOR]

Introduction: "Pelvic rib", "pelvic digit (finger)", or "eleventh digit (finger)" is a rare congenital anomaly, in which a finger-like bony structure is present in the soft tissue in the pelvic or abdomen (less common) area., Case Presentation: This case report presents a symptomatic "pelvic digit" discovered in a patient referred to the radiology department after prolonged unilateral hip pain, especially during long walks. To our knowledge, this is the first case report of unilateral pelvic digit occurrence in our region. It is an extremely rare condition that is often discovered incidentally due to the lack of clinical symptoms., Conclusion: To the best of the authors' knowledge, this is the tenth reported case of symptomatic pelvic digit in the literature and four of them have required surgical intervention.

Background: The purpose of this manuscript is to provide an in-depth literature review of the management of endometrial and cervical cancers with electronic brachytherapy., Materials and Methods: An extensive literature search was performed and 9 articles were selected based on preset criteria., Results: The reviewed studies provided dosimetric and clinical results. Patient populations were diverse and prescribed doses varied. When treatment plans were compared to those using cobalt 60 ( 60 Co) and iridium 192 ( 192 Ir) sources researchers found lower or equivalent doses in organs at risk while the doses at the applicator surface were significantly higher for electronic brachytherapy. In the eligible studies, a total of 72 patients received treatment with AxxentXoft vaginal applicator, 29 were treated with the Intrabeam vaginal applicator, and 8 with AxxentXoft cervical applicator., Conclusions: All authors found that electronic brachytherapy was safe and well tolerated as higher mucosal doses did not present as adverse clinical effects. Electronic brachytherapy for gynecological cancers has the potential to achieve equivalent tumor control while minimizing bowel and urinary toxicity thus improving the quality of life. More clinical data is needed to stratify patients who would benefit the most., Competing Interests: Conflict of interest None declared., (© 2023 Greater Poland Cancer Centre.)

Objectives: Constantly increasing number of procedures performed - endovascular or hybrid in patients with aortoiliac occlusive disease during the last decades finds its explanation in the lower morbidity and mortality rates, compared to bypass surgery. The purpose of the current survey was to estimate patients' radiation exposure in aortoiliac segment after endovascular or hybrid revascularization and to study the main factors which have direct contribution., Methods: A retrospective study of 285 procedures conducted with the help of a mobile C-arm system in 223 patients was performed. Procedures were grouped according to criteria such as: type of intervention, vascular access, level of complexity and operating team. Different analyses were performed within the groups and dose values., Results: The median values of kerma-air product (KAP), the number of series and the peak skin dose (PSD) significantly increase with the increasing number of vascular accesses: for one access (16.68 Gy.cm 2 , 6 and 336 mGy), for two (56.93 Gy.cm 2 , 11 and 545 mGy), and for three (102.28 Gy.cm 2 , 15 and 781 mGy). Significant dependence was observed in the case of single access site between the type of access and the dose values: hybrid and retrograde common femoral artery/superficial femoral artery (CFA/SFA) endovascular accesses, 10.06 Gy.cm 2 /301 mGy and 13.23 Gy.cm 2 /318 mGy respectively, in contrast with the contralateral CFA and left brachial access, 33 Gy.cm 2 /421 mGy and 38.33 Gy.cm 2 /448 mGy respectively., Conclusion: The results demonstrate that the most important factors increasing the dose values are number and type of vascular accesses, followed by the combination and number of implanted stents with the complexity of the procedure. The PSD values for a single procedure were between 2 and 12 times lower than those IAEA proposed as trigger levels for radiation-induced erythema. This study shows that trigger levels were not reached even for patients with repeated procedures in the same segment in 1-year period., Advances in Knowledge: The study gives important understanding and clarity on the growing awareness for dose-modifying factors during endovascular and hybrid revascularization of aortoiliac segment.

(1) Background: We aimed to analyze currently available studies with intraoperative radiotherapy (IORT) as a choice of treatment where the Xoft Axxent ® electronic brachytherapy (eBx) system was used as a single-dose irradiation and an exclusive radiotherapy approach at the time of surgery in patients with early breast cancer (EBC). We also compared the results of the systematic review to the Bulgarian experience. (2) Methods and Materials: We performed a systematic review of the studies published before February 2021, which investigate the application of a single-fraction 20 Gy radiation treatment, delivered at the time of lumpectomy in EBC patients with the Xoft Axxent ® eBx System. A systematic search in PubMed, Scopus, and ScienceDirect was performed. The results are reported following the PRISMA guidelines. The criteria on patients' selection for IORT (the additional need for EBRT), cosmetic outcomes, and recurrence rate from the eligible studies are compared to the treatment results in Bulgarian patients. (3) Results: We searched through 1032 results to find 17 eligible studies. There are no published outcomes from randomized trials. When reported, the cosmetic outcomes in most of the studies are defined as excellent. The observed recurrence rate is low (1-5.8%). Still, the number of patients additionally referred to postoperative external breast radiotherapy (EBRT) is up to 31%. Amongst the 20 patients treated in Bulgaria, the cosmetic outcomes are also evaluated as excellent, five of which (25%) are referred for EBRT. Within median follow-up of 39 months, there was one local and one distal recurrence. (4) Conclusions: Current evidence demonstrates the Xoft Axxent ® eBx system as a safe and feasible technique for IORT delivery in EBC patients. There are no randomized controlled trials conducted at this time point to prove its long-term effectiveness. Better patient selection and a reimbursement strategy have to be proposed to extend the application of this technique in Bulgaria.

Background There is lack of guidance on specific CT protocols for imaging patients with coronavirus disease 2019 (COVID-19) pneumonia. Purpose To assess international variations in CT utilization, protocols, and radiation doses in patients with COVID-19 pneumonia. Materials and Methods In this retrospective data collection study, the International Atomic Energy Agency coordinated a survey between May and July 2020 regarding CT utilization, protocols, and radiation doses from 62 health care sites in 34 countries across five continents for CT examinations performed in patients with COVID-19 pneumonia. The questionnaire obtained information on local prevalence, method of diagnosis, most frequent imaging, indications for CT, and specific policies on use of CT in COVID-19 pneumonia. Collected data included general information (patient age, weight, clinical indication), CT equipment (CT make and model, year of installation, number of detector rows), scan protocols (body region, scan phases, tube current and potential), and radiation dose descriptors (CT dose index and dose length product). Descriptive statistics and generalized estimating equations were performed. Results Data from 782 patients (median age, 59 years [interquartile range, 15 years]) from 54 health care sites in 28 countries were evaluated. Less than one-half of the health care sites used CT for initial diagnosis of COVID-19 pneumonia and three-fourths used CT for assessing disease severity. CT dose index varied based on CT vendors (7-11 mGy; P < .001), number of detector rows (8-9 mGy; P < .001), year of CT installation (7-10 mGy; P = .006), and reconstruction techniques (7-10 mGy; P = .03). Multiphase chest CT examinations performed at 20% of sites (11 of 54) were associated with higher dose length product compared with single-phase chest CT examinations performed in 80% of sites (43 of 54) ( P = .008). Conclusion CT use, scan protocols, and radiation doses in patients with coronavirus disease 2019 pneumonia showed wide variation across health care sites within the same and between different countries. Many patients were imaged multiple times and/or with multiphase CT scan protocols. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lee in this issue.

Purpose: Patients with hematuria and renal colic often undergo CT scanning. The purpose of our study was to assess variations in CT protocols and radiation doses for evaluation of hematuria and urinary stones in 20 countries., Method: The International Atomic Energy Agency (IAEA) surveyed practices in 51 hospitals from 20 countries in the European region according to the IAEA Technical cooperation classification and obtained following information for three CT protocols (urography, urinary stones, and routine abdomen-pelvis CT) for 1276 patients: patient information (weight, clinical indication), scanner information (scan vendor, scanner name, number of detector rows), scan parameters (such as number of phases, scan start and end locations, mA, kV), and radiation dose descriptors (CTDI vol , DLP). Two radiologists assessed the appropriateness of clinical indications and number of scan phases using the ESR Referral Guidelines and ACR Appropriateness Criteria. Descriptive statistics and Student's t tests were performed., Results: Most institutions use 3-6 phase CT urography protocols (80 %, median DLP 1793-3618 mGy.cm) which were associated with 2.4-4.9-fold higher dose compared to 2-phase protocol (20 %, 740 mGy.cm) (p < 0.0001). Likewise, 52 % patients underwent 3-5 phase routine abdomen- pelvis CT (1574-2945 mGy.cm) as opposed to 37 % scanned with a single-phase routine CT (676 mGy.cm). The median DLP for urinary stones CT (516 mGy.cm) were significantly lower than the median DLP for the other two CT protocols (p < 0.0001)., Conclusions: Few institutions (4/13) use low dose CT for urinary stones. There are substantial variations in CT urography and routine abdomen-pelvis CT protocols result in massive radiation doses (up to 2945-3618 mGy.cm)., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose: We present the development and the current state of the MaXIMA Breast Lesions Models Database, which is intended to provide researchers with both segmented and mathematical computer-based breast lesion models with realistic shape., Methods: The database contains various 3D images of breast lesions of irregular shapes, collected from routine patient examinations or dedicated scientific experiments. It also contains images of simulated tumour models. In order to extract the 3D shapes of the breast cancers from patient images, an in-house segmentation algorithm was developed for the analysis of 50 tomosynthesis sets from patients diagnosed with malignant and benign lesions. In addition, computed tomography (CT) scans of three breast mastectomy cases were added, as well as five whole-body CT scans. The segmentation algorithm includes a series of image processing operations and region-growing techniques with minimal interaction from the user, with the purpose of finding and segmenting the areas of the lesion. Mathematically modelled computational breast lesions, also stored in the database, are based on the 3D random walk approach., Results: The MaXIMA Imaging Database currently contains 50 breast cancer models obtained by segmentation of 3D patient breast tomosynthesis images; 8 models obtained by segmentation of whole body and breast cadavers CT images; and 80 models based on a mathematical algorithm. Each record in the database is supported with relevant information. Two applications of the database are highlighted: inserting the lesions into computationally generated breast phantoms and an approach in generating mammography images with variously shaped breast lesion models from the database for evaluation purposes. Both cases demonstrate the implementation of multiple scenarios and of an unlimited number of cases, which can be used for further software modelling and investigation of breast imaging techniques. The created database interface is web-based, user friendly and is intended to be made freely accessible through internet after the completion of the MaXIMA project., Conclusions: The developed database will serve as an imaging data source for researchers, working on breast diagnostic imaging and on improving early breast cancer detection techniques, using existing or newly developed imaging modalities., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Radiation-induced injuries to patient skin as a result of fluoroscopy guided interventional procedures are infrequently reported, often misdiagnosed and there is a need to learn lessons from every injury., Methods: This paper describes two cases of radiation induced skin injuries that are, to the best of our knowledge, the first ever reported cases from Bulgaria and possibly from Eastern Europe, and would thus have educational value., Results: The important messages from the skin injuries reported here are: lack of awareness among part of the interventional specialists about the potential for radiation induced skin injury, misdiagnosis after injury happened because of lack of awareness and knowledge among general physicians, dermatologists and surgeons who followed up cases of skin injuries; the lack of system to monitor patients with relatively high exposure; the important role played by the medical physicist in diagnosing the injury and overall in initiating actions; the role of training and informational material displayed in interventional facilities., Conclusions: For avoidance of skin injuries from interventional procedures it is of utmost importance to implement a system that includes (a) regular monitoring of radiation dose parameters of the procedure; (b) established trigger values for reporting;, ((c) procedure for patient follow-up if a trigger value is exceeded; (d) instructing the patient who has received exposure above the trigger value to self-examine the irradiated area of the skin for any itching/redness and report it back.)

In the period 2013-2016 the National Centre of Radiobiology and Radiation Protection (NCRRP) at the Ministry of Health of Bulgaria has developed a web based platform for performing national patient dose surveys and establishing Diagnostic Reference Levels (DRLs). It is accessible via internet browser, allowing the users to submit data remotely. Electronic questionnaires, specific for radiography, fluoroscopy, image guided interventional procedures, mammography and CT, were provided. Short and clear manuals were added to guide users and minimise human errors. The web-based data collection platform is functional and is currently being used for performing the third national dose survey in Bulgaria, launched in 2016. Data analysis is facilitated due to the standardisation of collected data and their storing. Using the platform, the participating facilities can establish their typical dose levels based on the median value, and compare them to DRLs. A disadvantage of the platform is the need to enter data manually, but it is opened for future upgrades for automatic data harvesting and analysis. Various practical approaches were used to overcome the lack of qualified human resources and insufficient understanding of the DRL and dose tracking concept and to motivate facilities to submit data., (Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The purpose of this work is to present the algorithm for the optimisation of paediatric chest radiography aimed to reduce patient doses at keeping adequate image quality. Optimal tube voltage, tube current and exposure time, use of automatic or manual exposure control and use of antiscatter grid were recommended for different age groups and depending on the patient size. The optimised protocols and radiography technique resulted in decrease in Entrance surface air kerma and effective dose values in a factor of between 1.5 and over 5 for different age groups. Image quality was assessed to be of sufficient diagnostic quality., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objective: To survey procedures and protocols in paediatric computed tomography (CT) in 40 less resourced countries., Methods: Under a project of the International Atomic Energy Agency, 146 CT facilities in 40 countries of Africa, Asia, Europe and Latin America responded to an electronic survey of CT technology, exposure parameters, CT protocols and doses., Results: Modern MDCT systems are available in 77 % of the facilities surveyed with dedicated paediatric CT protocols available in 94 %. However, protocols for some age groups were unavailable in around 50 % of the facilities surveyed. Indication-based protocols were used in 57 % of facilities. Estimates of radiation dose using CTDI or DLP from standard CT protocols demonstrated wide variation up to a factor of 100. CTDI(vol) values for the head and chest were between two and five times those for an adult at some sites. Sedation and use of shielding were frequently reported; immobilisation was not. Records of exposure factors were kept at 49 % of sites., Conclusion: There is significant potential for improvement in CT practice and protocol use for children in less resourced countries. Dose estimates for young children varied widely. This survey provides critical baseline data for ongoing quality improvement efforts by the IAEA.

Objective: The purpose of this study was to assess the frequency of pediatric CT in 40 less-resourced countries and to determine the level of appropriateness in CT use., Materials and Methods: Data on the increase in the number of CT examinations during 2007 and 2009 and appropriate use of CT examinations were collected, using standard forms, from 146 CT facilities at 126 hospitals., Results: The lowest frequency of pediatric CT examinations in 2009 was in European facilities (4.3%), and frequencies in Asia (12.2%) and Africa (7.8%) were twice as high. Head CT is the most common CT examination in children, amounting to nearly 75% of all pediatric CT examinations. Although regulations in many countries assign radiologists with the main responsibility of deciding whether a radiologic examination should be performed, in fact, radiologists alone were responsible for only 6.3% of situations. Written referral guidelines for imaging were not available in almost one half of the CT facilities. Appropriateness criteria for CT examinations in children did not always follow guidelines set by agencies, in particular, for patients with accidental head trauma, infants with congenital torticollis, children with possible ventriculoperitoneal shunt malfunction, and young children (< 5 years old) with acute sinusitis. In about one third of situations, nonavailability of previous images and records on previously received patient doses have the potential to lead to unnecessary examinations and radiation doses., Conclusion: With increasing use of CT in children and a lack of use of appropriateness criteria, there is a strong need to implement guidelines to avoid unnecessary radiation doses to children.

The purpose of this study was to explore the frequency of paediatric computed tomography (CT) examinations in several hospitals in Bulgaria and to assess the current practice. The standard forms provided by the International Atomic Emergency Agency for survey of the paediatric CT practice were used. Six hospitals provided data on frequency of paediatric CT examinations performed in 2009. Large variations in dose, up to a factor of 4, were found among the centres within the same age group for a given procedure, and in one of the hospitals the paediatric dose was twice higher than the adult dose. Seven departments use dedicated CT protocols for children. Only 4 in 12 departments keep records of patient dose. Dose information for previous examinations is not required by the radiologists. The collected detailed data provided preliminary information how the patient doses in paediatric CT can be reduced. Recommendations were given based on the findings.

The purpose of this study was to compare the important aspects of paediatric radiological practice and the patient doses from chest X-ray examinations performed in three hospitals in Bulgaria. Data from 163 paediatric patients were recorded using a standardised form. Entrance surface air kerma (ESAK) to patient was calculated from the air-kerma air product (KAP) and field size measurements. Large variations were found for KAP and ESAK. Inappropriate film size and insufficient collimation were often used. Inappropriate use of automatic exposure control and antiscatter grid was found. In most cases, no attention was paid to reduce dose to sensitive organs by means of shielding or proper collimation. Recommendations were given to the hospitals on how to reduce patient doses in paediatric chest radiography.