Images For Diagnostic Purposes Research Articles

Artificial Intelligence—The Rising Star in the Field of Gastroenterology and Hepatology

Artificial intelligence (AI) is a term that covers a multitude of techniques that are used in a manner that tries to reproduce human intelligence. AI is helpful in various medical specialties that use imaging for diagnostic purposes, and gastroenterology is no exception. In this field, AI has several applications, such as detecting and classifying polyps, detecting the malignancy in polyps, diagnosing Helicobacter pylori infection, gastritis, inflammatory bowel disease, gastric cancer, esophageal neoplasia, and pancreatic and hepatic lesions. The aim of this mini-review is to analyze the currently available studies regarding AI in the field of gastroenterology and hepatology and to discuss its main applications as well as its main limitations.

A convenient online desalination tube coupled with mass spectrometry for the direct detection of iodinated contrast media in untreated human spent hemodialysates.

Mass spectrometry (MS) analysis using direct infusion of biological fluids is often problematic due to high salts/buffers. Iodinated contrast media (ICM) are frequently used for diagnostic imaging purposes, sometimes inducing acute kidney injury (AKI) in patients with reduced kidney function. Therefore, detection of ICM in spent hemodialysates is important for AKI patients who require urgent continuous hemodiafiltration (CHDF) because it allows noninvasive assessment of the patient's treatment. In this study, we used a novel desalination tube before MS to inject the sample directly and detect ICM. Firstly, spent hemodialysates of one patient were injected directly into the electrospray ionization (ESI) source equipped with a quadrupole time-of-flight mass spectrometer (Q-TOF MS) coupled to an online desalination tube for the detection of ICM and other metabolites. Thereafter, spent hemodialysates of two patients were injected directly into the ESI source equipped with a triple quadrupole mass spectrometer (TQ-MS) connected to that online desalination tube to confirm the detection of ICM. We detected iohexol (an ICM) from untreated spent hemodialysates of the patient-administered iohexol for computed tomography using Q-TOF MS. Using MRM profile analysis, we have confirmed the detection of ICM in the untreated spent hemodialysates of the patients administered for coronary angiography before starting CHDF. Using the desalination tube, we observed approximately 178 times higher signal intensity and 8 times improved signal-to-noise ratio for ioversol (an ICM) compared to data obtained without the desalination tube. This system was capable of tracking the changes of ioversol in spent hemodialysates of AKI patients by measuring spent hemodialysates. The online desalination tube coupled with MS showed the capability of detecting iohexol and ioversol in spent hemodialysates without additional sample preparation or chromatographic separation. This approach also demonstrated the capacity to monitor the ioversol changes in patients' spent hemodialysates.

Anticancer Efficacy and Mechanisms of a Dual Targeting of Norepinephrine Transporter and Thyrointegrin αvβ3 Antagonist in Neuroblastoma.

Background: In neuroendocrine tumors, the norepinephrine transporter (NET) is very active and has been exploited for diagnostic imaging purposes and/or therapy with localized radiotherapy. Integrin αvβ3 is generously expressed by and/or activated on cancer cells, but not by nonmalignant cells.Purpose: In the present investigation, the anticancer efficacy of the dual targeting of norepinephrine transporter (NET), benzylguanidine (BG), and thyrointegrin αvβ3 receptors antagonist triazole tetraiodothyroacetic acid (TAT) conjugated via the non-cleavable linker polyethylene glycol (P, PEG400) in the treatment of human neuroblastoma was evaluated.Experimental approach: The synthesized dual targeting compound, a novel new chemical entity named BG-P400-TAT, has purity > 98% and was formulated and tested in neuroblastoma models using neuroblastoma cell lines (SK-N-FI, SMS-KCN and SMS-KANR) implanted in SCID and NSG mice models.Key Results: BG-P400-TAT demonstrated significant (**P<0.01, ***P< 0.001) suppression of neuroblastoma tumor progression, growth, and viability in both mice models implanted with the neuroblastoma. The pharmacokinetic and biodistribution profile of BG-P400-TAT showed a significant increase in BG-P400-TAT levels in plasma and xenografts of NSG compared to SCID mice. Further our RNAseq genome-wide expression profiling experiments in neuroblastoma cell line SKNAS results showed that BG-P400-TAT treatment altered the signal transduction pathways, intracellular multiprotein complexes and Independent GSEA.Conclusion & Implications: BG-P400-TAT represents a potential lead candidate for the treatment of neuroblastoma and other neuroendocrine tumors.

High-Intensity Focused Ultrasound: A Review of Mechanisms and Clinical Applications.

High Intensity Focused Ultrasound (HIFU) is an emerging and increasingly useful modality in the treatment of cancer and other diseases. Although traditional use of ultrasound at lower frequencies has primarily been for diagnostic imaging purposes, the development of HIFU has allowed this particular modality to expand into therapeutic use. This non-invasive and acoustic method involves the use of a piezoelectric transducer to deliver high-energy pulses in a spatially coordinated manner, while minimizing damage to tissue outside the target area. This review describes the history of the development of diagnostic and therapeutic ultrasound and explores the biomedical applications utilizing HIFU technology including thermally ablative treatment, therapeutic delivery mechanisms, and neuromodulatory phenomena. The application of HIFU across various tumor types in multiple organ systems is explored in depth, with particular attention to successful models of HIFU in the treatment of various medical conditions. Basic mechanisms, preclinical models, previous clinical use, and ongoing clinical trials are comparatively discussed. Recent advances in HIFU across multiple medical fields reveal the growing importance of this biomedical technology for the care of patients and for the development of possible pathways for the future use of HIFU as a commonplace treatment modality.

Personalised Profiling of Innate Immune Memory Induced by Nano-Imaging Particles in Human Monocytes.

Engineered nanoparticles used for medical purposes must meet stringent safety criteria, which include immunosafety, i.e., the inability to activate possibly detrimental immune/inflammatory effects. Even medical nanomaterials devoid of direct immunotoxic or inflammatory effects may have an impact on human health if able to modify innate memory, which is the ability to “prime” future immune responses towards a different, possibly more detrimental reactivity. Although innate memory is usually protective, anomalous innate memory responses may be at the basis of immune pathologies. In this study, we have examined the ability of two nanomaterials commonly used for diagnostic imaging purposes, gold and iron oxide nanoparticles, to induce or modulate innate memory, using an in vitro model based on human primary monocytes. Monocytes were exposed in culture to nanoparticles alone or together with the bacterial agent LPS (priming phase/primary response), then rested for six days (extinction phase), and eventually challenged with LPS (memory/secondary response). The memory response to the LPS challenge was measured as changes in the production of inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10, IL-1Ra), as compared to unprimed monocytes. The results show that both types of nanoparticles can have an effect in the induction of memory, with changes observed in the cytokine production. By comparing nanomaterials of different shapes (spherical vs. rod-shaped gold particles) and different size (17 vs. 22 nm diameter spherical iron oxide particles), it was evident that innate memory could be differentially induced and modulated depending on size, shape and chemical composition. However, the main finding was that the innate memory effect of the particles was strongly donor-dependent, with monocytes from each donor showing a distinct memory profile upon priming with the same particles, thereby making impossible to draw general conclusions on the particle effects. Thus, in order to predict the effect of imaging nanoparticles on the innate memory of patients, a personalised profiling would be required, able to take in consideration the peculiarities of the individual innate immune reactivity.

Manually scanned single fiber optical coherence tomography for skin cancer characterization

Optical coherence tomography (OCT) is a cross-sectional imaging modality based on low coherence light interferometry. Within dermatology, it has found applications for in vivo diagnostic imaging purposes, as well as to guide Mohs micrographic surgery (MMS), due to its ability to visualize skin morphology up to several millimeters in depth. However, standard OCT probes have a large footprint and capture an extended area of the skin, making it difficult to precisely pinpoint clinically relevant location being imaged. Mohs surgeons stand to benefit from a handheld in vivo imaging device that can accurately trace surgical margins. In this study, we demonstrate the use of a single fiber OCT (sfOCT) instrument. Our imaging system features a miniature common path single fiber probe, and a novel speckle decorrelation technique that generates distortion free 2D images from manual scanning.By manually moving the single-fiber probe across the region of interest, the user can perform a lateral OCT scan while visualizing the location of the probe during data acquisition. Using the sfOCT, we have identified normal skin morphology, qualitatively correlated features of basal cell carcinoma and squamous cell carcinoma with histopathology, and quantified the disruption of the dermo-epidermal junction OCT pattern in skin tumors—each demonstrating the potential of utilizing sfOCT to differentiate tumor from normal skin. Using this imaging tool, a Mohs surgeon can enhance determination of surgical margins for the first stage of MMS, potentially decreasing the time and number of stages required for complete tumor removal.

A case for mandatory ultrasound training for rural general practitioners: a commentary.

Point-of-care ultrasound is a rapidly evolving technology that enables rapid diagnostic imaging to be performed at a patient's bedside, reducing time to diagnosis and minimising the need for patient transfers. This has significant applications for rural emergency and general practice, and could potentially prevent unnecessary transfers of patients from rural communities to more urban centres for the purpose of diagnostic imaging, reducing costs and preventing disruption to patients' lives. Meta-analyses on point-of-care ultrasound have reported extremely high sensitivity and specificity when detecting lung pathology, and the potential applications of the technology are substantial. A significant application of the technology is in the care of rural paediatric patients, where acute lower respiratory pathology is the most common cause of preventable deaths, hospitalisations, and emergency medical retrievals from remote communities for children under five. Although widely available, point-of-care ultrasound technology is not widely utilised in Australian emergency departments and general practices. Issues with comprehensive training, maintenance of skills, upskilling and quality assurance programs prevent physicians from feeling confident when utilising the technology. In Canada, point-of-care ultrasound training is part of the core competency training in the Royal College of Physicians of Canada emergency medicine fellowship program. Point-of-care ultrasound is widely used in rural practice, although lack of training, funding, maintenance of skills and quality assurance were still listed as barriers to use. Point-of-care ultrasound is a highly sensitive and specific technology with wide potential applications. Issues with quality control and maintenance of skills are preventing widespread use. Coupling point-of-care ultrasound with telemedicine could help increase the usability and accessibility of the technology by reducing the issues associated with maintenance of skills and quality assurance.

Multi detector computed tomography in maxillofacial injuries

Background: Imaging is an important step after the clinical evaluation in the workup of patients with facial trauma .It helps to define the extent of injury and to plan the surgical, interventional, or conservative therapy. Multidetector computed tomography (MDCT) is the imaging technique of choice to detect and characterize the number of fractures, fragments, the degree of dislocation, and the involvement of anatomical structures. It provides a three-dimensional (3D) mapping of the smallest fractures and abnormalities in a short period of time in trauma and emergency setting.Results: The study included 30 patients with mean age of 41.07± 13.92 years with age range of 21 – 68 years. In most of the cases the mode of injury was road traffic accidents among 23(76.7%). Fracture maxilla in 63.3% followed by mandible in 56.7% was the most common bone involved in facial fractures. Hemosinus (56.7%) was the most common associated finding in the patients who presented with facial trauma. Brain contusions were the next common finding seen in 30% patients. Medial wall of the orbit was the most common wall involved in orbital fractures. The mandibular injuries were most common in the condyle and the body of the mandible. Le Fort fracture lines were identified in 17 patients with the most common Le Fort line being the Le Fort II & Le Fort III which was seen 7 patients (23.3%) each.Conclusion: The complex anatomy of the facial bones requires multiplanar imaging techniques for a proper evaluation. The main purpose of diagnostic imaging is to detect and localize the exact number, site of facial fractures and soft tissue injuries. 3D images are useful, although variable for different bones, in the assessment of complex fractures involving the face. Coronal images are useful adjunct in detection of facial fractures. MDCT offers excellent spatial resolution, which in turn enables exquisite multiplanar reformations, and 3-D reconstructions, allowing enhanced diagnostic accuracy and surgical planning.

Fractal dimension of external linear contour of human cerebellum (magnetic resonance imaging study)

Fractal analysis is a method of mathematical analysis, which provides quantitative assessment of the spatial configuration complexity of the anatomical structures and may be used as a morphometric method. The purpose of the study was to determine the values of the fractal dimension of the outer linear contour of human cerebellum by studying the magnetic resonance images of the brain using the authors’ modification of the caliper method and compare to the values determined using the box counting method. Brain magnetic resonance images of 30 relatively healthy persons aged 18-30 years (15 men and 15 women) were used in the study. T2-weighted digital magnetic resonance images were studied. The midsagittal MR sections of the cerebellar vermis were investigated. The caliper method in the author’s modification was used for fractal analysis. The average value of the fractal dimension of the linear contour of the cerebellum, determined using the caliper method, was 1.513±0.008 (1.432÷1.600). The average value of the fractal dimension of the linear contour of the cerebellum, determined using the box counting method, was 1.530±0.010 (1.427÷1.647). The average value of the fractal dimension of the cerebellar tissue as a whole, determined using the box counting method, was 1.760±0.006 (1.674÷1.837). The values of the fractal dimension of the outer linear contour of the cerebellum, determined using the caliper method and the box counting method were not statistically significantly different. Therefore, both methods can be used for fractal analysis of the linear contour of the cerebellum. Fractal analysis of the outer linear contour of the cerebellum allows to quantify the complexity of the spatial configuration of the outer surface of the cerebellum, which is difficult to estimate using traditional morphometric methods. The data obtained from this study and the methodology of the caliper method of fractal analysis in the author’s modification can be used for morphometric investigations of the human cerebellum in morphological studies, as well as in assessment of cerebellar MR images for diagnostic purposes.

Transformation acoustics for beamforming in anisotropic media

Acoustic wave propagation in anisotropic media like tissue and other biomaterials is important for biomedical acoustics, as ultrasound is commonly used as a technique for non-invasive surgeries and diagnostic imaging purposes. These ultrasound applications require beamformed signals to target specific regions of the body. However, the anisotropic properties of the body (e.g., muscle fibers) distort the beamformed wavefronts, detrimental to the performance of ultrasound therapies and imaging. Here, we propose and experimentally demonstrate a unique transformation acoustic technique that corrects the anisotropic distortive effects to beamform an arbitrarily desired propagation pattern. The experimental measurements demonstrate the effectiveness of this transformation acoustic correction for arbitrary focusing and selfbending beams. Our work provides an important method to suppress undesired anisotropic effects on beamformed waves, to improve upon the precision and effectiveness of medical treatments and diagnostics facilitated by noninvasive ultrasound therapies and imaging.

Normal Pancreas Graft Appearance in Magnetic Resonance Diffusion Tensor Imaging (DTI).

BackgroundThe main purpose of diagnostic imaging after pancreas transplantation is to exclude potential complications. As long as standard anatomical imaging such as sonography, contrast-enhanced computed tomography, and magnetic resonance imaging (MRI) are sufficient to display macroscopic vasculature, early changes within the graft caused by insufficient microperfusion will not be displayed for evaluation.Material/MethodsPatients with pancreas allograft function in good condition were included in the study. No specific preparation was demanded before the MRI examination. The results of MRI were correlated with Igls criteria. It was a preliminary study to examine diffusion tensor imaging (DTI) value and safety in pancreas transplantation.ResultsOur results indicated that higher fractional anisotropy (FA) values of the graft’s head were associated with delayed graft function and insulin intake. We also compared grafts’ images in early and late periods and found differences in T1 signal intensity values. DTI is a reliable noninvasive tool, requiring no contrast agent, to assess graft microstructure in correlation with its function, with FA values showing the most consistent results. By Igls criteria, no graft failure, 76% had optimal function, 10% had good function, and 14% had marginal function.ConclusionsOur results suggest that DTI can be safely used in patients after pancreas transplantation and is advantageous in detecting early as well as late postoperative complications such as intra-abdominal fluid collection, malperfusion, and ischemia of the graft. Our findings correspond with clinical condition and Igls criteria. DTI is free of ionizing agents and is safe for kidney grafts.

Pediatric applications of Dotatate: early diagnostic and therapeutic experience.

In recent years, new somatostatin receptor agents (SSTRs) have become available for diagnostic imaging and therapy in neuroendocrine tumors. The novel SSTR ligand DOTA-DPhel-Tyr3-octreotate (Dotatate) in particular can be linked with 68Gallium for diagnostic imaging purposes, and with the β-emitter 177Lutetium for radiotherapy in the setting of neuroendocrine tumors. Dotatate imaging offers distinct advantages in the evaluation of neuroendocrine tumors compared to standard techniques, including greater target-to-background ratio and lesion conspicuity, high sensitivity/specificity, improved spatial resolution with positron emission tomography (PET)/CT or PET/MR, and decreased radiation exposure. Although currently off-label in pediatrics, Dotatate theranostics in children are being explored, most notably in the setting of neuroblastoma and hereditary neuroendocrine syndromes. This article provides a multicenter case series of Dotatate imaging and therapy in pediatric patients in order to highlight the spectrum of potential clinical applications.

The development of a clinically tested visually lossless Image compression system for capsule endoscopy

Background and objective:Capsule endoscopy investigations currently capture a large number of images that must be processed and transferred inside the capsule. This demands a compression system that is capable of reducing the amount of data processed, encoded and transmitted. In comparison to a lossless system, a near-lossless image compression approach would have lower complexity and reduce the amount of data processed inside the capsule. However, the visual quality of the images compressed using a near-lossless approach must be deemed suitable for diagnostic use by clinicians. Methods:This paper outlines the development and clinical validation of a near-lossless image compression approach based on a Simplified Structure Conversion method, an Optimized Difference Approach, and a Golomb–Rice encoder. Eighteen clinicians participated to assess the suitability of processed videos and images for diagnostic purposes. Results:Our near-lossless approach returned a Peak Signal to Noise Ratio (PSNR) of 43.89182 dB and Structural Similarity measure of 0.996746 and an overall compression ratio (CR) of 5:1. Clinicians assessed the videos compressed by the developed system and rated 82% of the videos as acceptable for diagnostic purposes. Clinicians also compared the images before and after processing with the developed system and rated 86% of the images as “no difference”. Conclusion:The high values of the MSSIM, PSNR, CR and the high acceptance of clinicians provided a reliable indication of the high performance of the developed compression system. This matches the image quality requirements of capsule endoscopy for real-world medical diagnosis.

Anatomic Variation of the Submandibular Gland: A Case Report

The Human Anatomy is an ancient Science, which uses the human body as the main material of study. However, structural differences between individuals that make up the species are quite common in the population and always emerge as a source of reports that aim to demonstrate and clarify these differences. These structural changes are called anatomical variations and may be presented externally or internally in any of the body systems, with no functional impairment to the individual. The salivary glands are exocrine glands that secrete saliva directly into the mouth through their ducts. This secretion has the functions of keeping mucous membranes moist, cleaning teeth, lubricating, dissolving and starting the food digestion process. Most of the saliva is secreted by the major salivary glands, the parotid glands and the submandibular glands, the latter being the focus of this case report. The purpose of this paper is to report a case of finding an accessory submandibular gland on a cadaver from the Human Anatomy Laboratory of the University Center of Rio Grande do Norte located in Natal, Rio Grande do Norte, Brazil. The discovery was made during a dissection of an adult male body in 2012, where an accessory submandibular gland was found in the right antimere. Thus, by identifying such variations, its clinical importance can be observed for the purpose of diagnostic imaging, surgery and anatomical teaching applied to clinic, given the scarcity of published reports, thus providing better understanding those working directly or indirectly on the subject.

The Role of Autophagy in Nanoparticles-Induced Toxicity and Its Related Cellular and Molecular Mechanisms.

In the past decades, nanoparticles have been widely used in industry and pharmaceutical fields for drug delivery, anti-pathogen, and diagnostic imaging purposes because of their unique physicochemical characteristics such as special ultrastructure, dispersity, and effective cellular uptake properties. But the nanotoxicity has been raised over the extensive applications of nanoparticles. Researchers have elucidated series of mechanisms in nanoparticles-induced toxicity, including apoptosis, necrosis, oxidative stress, and autophagy. Among upon mechanisms, autophagy was recently recognized as an important cell death style in various nanoparticles-induced toxicity, but the role of autophagy and its related cellular and molecular mechanisms during nanoparticles-triggered toxicity were still confusing. In the chapter, we briefly introduced the general process of autophagy, summarized the different roles of autophagy in various nanoparticle-treated different in vitro/in vivo models, and deeply analyzed the physicochemical and biochemical (cellular and molecular) mechanisms of autophagy during nanoparticles-induced toxicity through listing and summarizing representative examples. Physicochemical mechanisms mainly include dispersity, size, charge, and surface chemistry; cellular mechanisms primarily focus on lysosome impairment, mitochondria dysfunction, mitophagy, endoplasmic reticulum stress and endoplasmic reticulum autophagy; while molecular mechanisms were mainly including autophagy related signaling pathways, hypoxia-inducible factor, and oxidative stress. This chapter highlighted the important role of autophagy as a critical mechanism in nanoparticles-induced toxicity, and the physicochemical and biochemical mechanisms of autophagy triggered by nanoparticles might be useful for establishing a guideline for the evaluation of nanotoxicology, designing and developing new biosafety nanoparticles in the future.

Inefficiency, dignity and patient experience: is it time for separate outpatient diagnostics?

There is international and national variation in the location of diagnostic imaging centres relative to hospitals. Diagnostic cross-sectional imaging has traditionally been performed within a hospital, catering for both inpatient and outpatients. The resulting two-tiered system caters for emergent and complex inpatients, in addition to typically ambulatory outpatients. These outpatients are less complex, and often attend an acute hospital for the specific purpose of diagnostic imaging. In both the UK and the Republic of Ireland, outpatient radiology is often provided on-campus in state-funded hospitals, reflecting the allocation of resources nationally. In many other countries, hospitals provide acute and high-level care, with community centres addressing outpatients' clinical and diagnostic needs. Mixing inpatients and outpatients introduces variability into the scanning process, and many institutions struggle to provide for the very different needs of outpatients. Current strategies of mixing these two fundamentally different groups should be reassessed, and either in-hospital segregation or dedicated outpatient diagnostic imaging centres merit serious consideration in any future healthcare planning.

Evaluation of different teaching methods for FAST examination: high fidelity simulation versus traditional training

Background The Focused Assessment with Sonography for Trauma (FAST) is used to identify free fluids. It is highly sensitive and specific if performed by experienced physicians. The most complex part of the learning curve is represented by the acquisition of adequate images for diagnostic purposes. Hence it is of primary importance to properly handle the ultrasound probe and to identify its correct position and orientation on patients. High fidelity simulation (HFS) might provide an efficient way of learning by reproducing realistic and rare situations. However, although some ultrasound simulators are commercially available, none is of low cost, suitable for every medical discipline and specifically designed for HFS and made for any mannequin.

Will the future of knowledge work automation transform personalized medicine?

Today, we live in a world of ‘information overload’ which demands high level of knowledge-based work. However, advances in computer hardware and software have opened possibilities to automate ‘routine cognitive tasks’ for knowledge processing. Engineering intelligent software systems that can process large data sets using unstructured commands and subtle judgments and have the ability to learn ‘on the fly’ are a significant step towards automation of knowledge work. The applications of this technology for high throughput genomic analysis, database updating, reporting clinically significant variants, and diagnostic imaging purposes are explored using case studies.

Antibody-based imaging strategies for cancer.

Although mainly developed for preclinical research and therapeutic use, antibodies have high antigen specificity, which can be used as a courier to selectively deliver a diagnostic probe or therapeutic agent to cancer. It is generally accepted that the optimal antigen for imaging will depend on both the expression in the tumor relative to normal tissue and the homogeneity of expression throughout the tumor mass and between patients. For the purpose of diagnostic imaging, novel antibodies can be developed to target antigens for disease detection, or current FDA-approved antibodies can be repurposed with the covalent addition of an imaging probe. Reuse of therapeutic antibodies for diagnostic purposes reduces translational costs since the safety profile of the antibody is well defined and the agent is already available under conditions suitable for human use. In this review, we will explore a wide range of antibodies and imaging modalities that are being translated to the clinic for cancer identification and surgical treatment.

Characterization of calibration curves and energy dependence GafChromic™ XR-QA2 model based radiochromic film dosimetry system.

The authors investigated the energy response of XR-QA2 GafChromic™ film over a broad energy range used in diagnostic radiology examinations. The authors also made an assessment of the most suitable functions for both reference and relative dose measurements. Pieces of XR-QA2 film were irradiated to nine different values of air kerma in air, following reference calibration of a number of beam qualities ranging in HVLs from 0.16 to 8.25 mm Al, which corresponds to effective energy range from 12.7 keV to 56.3 keV. For each beam quality, the authors tested three functional forms (rational, linear exponential, and power) to assess the most suitable function by fitting the delivered air kerma in air as a function of film response in terms of reflectance change. The authors also introduced and tested a new parameter χ = netΔR·e(m netΔR) that linearizes the inherently nonlinear response of the film. The authors have found that in the energy range investigated, the response of the XR-QA2 based radiochromic film dosimetry system ranges from 0.222 to 0.420 in terms of netΔR at K(air)(air) = 8 cGy. For beam qualities commonly used in CT scanners (4.03-8.25 mm Al), the variation in film response (netΔR at K(air)(air) = 8 cGy) amounts to ± 5%, while variation in K(air)(air) amounts to ± 14%. Results of our investigation revealed that the use of XR-QA2 GafChromic™ film is accompanied by a rather pronounced energy dependent response for beam qualities used for x-ray based diagnostic imaging purposes. The authors also found that the most appropriate function for the reference radiochromic film dosimetry would be the power function, while for the relative dosimetry one may use the exponential response function that can be easily linearized.