Radiation Medical Imaging Research Articles

Synchrotron X-ray Radiation (SXR) in Medical Imaging: Current Status and Future Prospects

Synchrotron X-ray radiation (SXR) has been widely studied to explore the structure of matter. Recently, there has been an intense focus on the medical application of SXR in imaging. This review is intended to explore the latest applications of SXR in medical imaging and to shed light on the advantages and drawbacks of this modality. The article highlights the latest developments in other fields that can greatly enhance the capability and applicability of SXR. The potentials of using machine and deep learning (DL)-based methods to generate synthetic images to use in regular clinics along with the use of photon counting X-ray detectors for spectral medical imaging with SXR are also discussed.

Metrology for radiation protection: a new European network in the foundation phase

Abstract. More than 23 million workers worldwide are occupationally exposed to ionizing radiation and all people in the world are exposed to environmental radiation. The mean exposure, that is the mean annual dose of per person, is dominated by medical applications and exposure to natural sources. Due to recent developments in healthcare, e.g. the increasing application of ionising radiation in medical imaging with relative high doses like CT, and modern high dose applications (for example CT angiography), the exposure due to medical application has risen. Additionally, the changes in living conditions increase the exposure to natural radioactivity also: More living time is spent in buildings or in an urban environment, which causes higher exposure to Naturally Occurring Radioactive Materials (NORM) in building materials and higher exposure to radon. The level of radon activity concentration in buildings is far higher than in the environment (outdoor). This effect is often amplified by modern energy-efficient buildings which reduce the air exchange and thus increase the radon indoor activity concentration. In summary both medical application of ionizing radiation and natural sources are responsible for the increase of the mean annual exposure of the population. The accurate measurement of radiation dose is key to ensuring safety but there are two challenges to be faced: First, new standards and reference fields are needed due to the rapid developments in medical imaging, radiotherapy and industrial applications. Second, direct communication channels are needed to ensure that information on best practice in measurements reaches effectively and quickly the people concerned. It is therefore necessary to allow for an international exchange of information on identified problems and solutions. Consequently, a European Metrology Network (EMN) for radiation protection under the roof of EURAMET is in the foundation phase. This network EMN for Radiation Protection is being prepared by the project EMPIR 19NET03 supportBSS. The project aims to prepare this EMN by addressing this issue through the identification of stakeholder research needs and by implementing a long-term ongoing dialogue between stakeholders and the metrology community. The EMN will serve as a unique point of contact to address all metrological needs related to radiation protection and it will relate to all environmental processes where ionising radiation and radionuclides are involved. A Strategic Research Agenda and two roadmaps are in development, covering the metrology needs of both the Euratom Treaty and the EU Council Directive 2013/59/EURATOM pinning down the basic safety standards for protection against the dangers arising from exposure to ionizing radiation. Furthermore, long-term knowledge sharing, and capacity building will be supported and a proposal for a sustainable joint European metrology infrastructure is under way. This will significantly strengthen the radiation protection metrology and support radiation protection measures. The final goal of the network project is a harmonised, sustainable, coordinated and smartly specialised infrastructure to underpin the current and future needs expressed in the European regulations for radiation protection.

Cancer risk of CT scan in COVID-19: Resolving the dilemma.

Cancer risk of CT scan in COVID-19: Resolving the dilemma.

Measurement of mass attenuation coefficient of polyvinyl alcohol (PVAL) as breast tissue equivalent material in the photon energy range of 16.61–25.26 keV

Medical physics phantom is commonly designed to mimic physical properties of human tissue. Phantom is widely used to provide quantitative and qualitative information upon its interaction with ionizing radiation in medical imaging, radiation dosimetry and treatment planning procedures. This study was carried out to fabricate a potential medical physics phantom material for mammography using polyvinyl alcohol (PVAL). The mass attenuation coefficients (μ/ρ ) of the PVAL gel samples were calculated based on the measurement of attenuation coefficient studies with low photon energy. The gel samples were prepared at 4 concentrations (5, 10, 15 and 20 %) of PVAL solution. Single photon beam transmission in the energy range between 16.61 and 25.26 keV was used to determine the μ/ρ of the PVAL gel. The low photon energy was chosen as the effective energy used in mammography is in a range between 17.5 to 22.6 keV. This was achieved by using the X-ray fluorescent (XRF) configuration. The experimental μ/ρ were compared with theoretical values of water and breast tissue calculated by using the XCOM computer program. The measured value of μ/ρ of the PVAL gels agreed with the XCOM values of water and breast tissue. The 5% and 10% PVAL gel samples were the closest to water while the 20% PVAL was the closest to breast tissue.

Ionising radiation exposure from medical imaging – A review of Patient's (un) awareness

IntroductionMedical imaging is the main source of artificial radiation exposure. Evidence, however, suggests that patients are poorly informed about radiation exposure when attending diagnostic scans. This review provides an overview of published literature with a focus on nuclear medicine patients on the level of awareness of radiation exposure from diagnostic imaging. MethodsA review of available literature on awareness, knowledge and perception of ionising radiation in medical imaging was conducted. Articles that met the inclusion criteria were subjected to critical appraisal using the Mixed Methods Appraisal Tool. Results140 articles identified and screened for eligibility, 24 critically assessed and 4 studies included in synthesis. All studies demonstrated that patients were generally lacking awareness about radiation exposure and highlighted a lack of communication between healthcare professionals and patients with respect to radiation exposure. ConclusionStudies demonstrate a need to better inform patients about their radiation exposure, and further studies focusing on nuclear medicine patients are particularly warranted. Implications for practiceAdequate and accurate information is crucial to ensure the principle of informed consent is present.

Informed consent guidelines for ionising radiation examinations: A Delphi study

IntroductionInformed consent for ionising radiation medical imaging examinations is currently undertaken inconsistently in Australian radiographic practice. There is no uniform informed consent process, and opinions vary about how it should be undertaken, and by whom, if indeed it needs to be undertaken at all.To ensure that patients’ rights are maintained, the informed consent process must be consistent, proactive in the provision of information, and must empower the patient to formulate and ask questions about their care, and to make voluntary decisions. MethodsThe Delphi technique utilises a group of experts whose individual responses are used to create a collective consensus on a process. This ten-expert (five radiographer, five radiologist) Delphi study examined a basic modelling of the process of informed consent for ionising radiation medical imaging examinations and made recommendations for an ideal process. ResultsA series of consensus statements were developed, seeking to rectify areas of the process that were inconsistent, unclear, or ethically unsound. These statements were then considered alongside current codes of professional practice, and Australian law on the duty of disclosure. A model of the ideal process was then developed using these consensus statements and adhering to codes of practice. ConclusionThe final process model has a continuity of care and a continuity of information provision. The model eliminates the radiographer as a delegatee, and emphasises physician involvement. The referrer and the radiologist have a shared responsibility of providing risk disclosure information.Implications for Practice: For a non-pregnant adult, the ionising radiation dose from conventional radiography is considered insignificant, and does not require risk disclosure, ameliorating the time commitment needed for the process.

Knowledge, attitude and practice of nuclear medicine staff towards radiation protection

Introduction: Ionizing radiation in medical imaging is one of the dominant sources of exposure, and correct knowledge of radiation protection, affects staff safety behaviors during procedures. This study aimed to assess the radiation protection Knowledge, Attitude and Practice (KAP) amongst nuclear medicine centers' staff in Iran. Methods: To evaluate the level of radiation protection KAP, a validated questionnaire was distributed between 243 participants considering demographic characteristics in different geographical regions in Iran from 2014 to 2015. Results: There were statistically significant differences in the level of nuclear medicine staff KAP radiation protection with gender (p<0.05), practice age KAP level and radiation protection (p<0.05) among nuclear medicine staff with different working regions and healthcare market. There is no significant connection between educational age and KAP level of radiation protection of nuclear medicine department staff (p>0.05). Conclusion: Our findings have shown that radiation protection KAP level of nuclear medicine staff was inadequate in some regions. This might be due to the lack of continuous training and absence of adequate safety knowledge about ionizing radiation. It seems that awareness about radiation protection rules and regulations, along with continuous training and preparations has a direct effect on radiation practice leading to enhanced KAP of staff in nuclear medicine centers.

Barriers and pathways to informed consent for ionising radiation imaging examinations: A qualitative study

IntroductionInformed consent for ionising radiation medical imaging examinations represents a recent change to medical imaging practice. This practice has not had a definitive and authoritative integration into clinical practice, and lack of direction has caused many health care professionals to be unsure of an appropriate consent methodology. Consent practices have been undertaken inconsistently and sometimes poorly. This research sought to investigate what barriers exist to meaningful informed consent, and what pathways are suggested to overcome these barriers. These views are then discussed in the context of practical health care consent practices. MethodsA semi-structured interview explored the views of radiographers and radiologists on the practice of disclosing the ionising radiation risk of a clinical medical imaging examination. Qualitative data was analysed using a nominal method of quantitative transformation. Responses were reviewed, and a set of definitive themes constructed. Participants considered the influences, logistics and barriers to the informed consent process. Participants were then asked what pathways might be developed that would improve the process. ResultsTwenty-one (21) radiographer participants and nine (9) radiologists were interviewed. The barriers to consent identified issues of time constraints, lack of a unified message, and patient presentations. Pathways suggested included limiting the scope of the consent practice, sharing the consent responsibility, and formulation of definitive consent guidelines. ConclusionA unified, definitive series of guidelines for informed consent for ionising radiation examinations would alleviate many of the identified barriers. Having the consent process consistently begin with the referring doctor would facilitate more meaningful consent.

Understanding, justifying, and optimizing radiation exposure for CT imaging in nephrourology.

An estimated 4-5 million CT scans are performed in the USA every year to investigate nephrourological diseases such as urinary stones and renal masses. Despite the clinical benefits of CT imaging, concerns remain regarding the potential risks associated with exposure to ionizingradiation. To assess the potential risk of harmful biological effects from exposure toionizing radiation, understanding the mechanisms by which radiation damage and repair occur is essential. Although radiation level and cancer risk follow a linear association at high doses, no strong relationship is apparent below 100 mSv, the doses used in diagnostic imaging. Furthermore, the small theoretical increase in risk of cancer incidence must be considered in the context of the clinical benefit derived from a medically indicated CT and the likelihood of cancer occurrence in the general population. Elimination of unnecessary imaging is the most important method to reduce imaging-related radiation; however, technical aspects of medically justified imaging should also be optimized, such that the required diagnostic information is retained while minimizing the dose of radiation. Despite intensive study, evidence to prove an increased cancer risk associated with radiation doses below ~100 mSv is lacking; however, concerns about ionizing radiation in medical imaging remain and can affect patient care. Overall, the principles of justification and optimization must remain the basis of clinical decision-making regarding the use of ionizing radiation in medicine.

Children, medical radiation and the environment: An important dialogue

There are unique considerations in the medical care of children, which includes the use of medical imaging. Medical imaging is frequently necessary and is essential in diagnosis and management of children with illness and injury. Much of medical imaging requires ionizing radiation. While virtually all diagnostic imaging radiation is considered low-dose level, there is still a broad misperception about what modalities use ionizing radiation and how much radiation risk exists in the medical environment. A discussion of radiation exposure is especially relevant in children due to their increased vulnerability, including to radiation-induced cancer. Ionizing radiation is both naturally occurring and man-made, including medical sources that have been increasing over the past few decades and can vary in radiation dose both between different modalities and for similar examinations. Perspectives vary regarding cancer risk and levels of radiation resulting from diagnostic imaging, however most medical and scientific organization support the perspective that the risk of cancer at these levels is uncertain. It is important to have balanced and informed resources for the use of ionizing radiation in the care of children, and it is equally important to assure that the delivery of this content is appropriate to the audience to which it is intended. For these reasons, it is valuable to review the issues related to use of ionizing radiation in medical imaging in children.

Knowledge of Radiation Hazards, Radiation Protection Practices and Clinical Profile of Health Workers in a Teaching Hospital in Northern Nigeria.

Use of ionizing radiation in medical imaging for diagnostic and interventional purposes has risen dramatically in recent years with a concomitant increase in exposure of patients and health workers to radiation hazards. To assess the knowledge of radiation hazards, radiation protection practices and clinical profile of health workers in UDUTH, Sokoto, Nigeria. A cross-sectional study was conducted among 110 Radiology, Radiotherapy and Dentistry staff selected by universal sampling technique. The study comprised of administration of standardized semi-structured pre-tested questionnaire (to obtain information on socio-demographic characteristics, knowledge of radiation hazards, and radiation protection practices of participants), clinical assessment (comprising of chest X-ray, abdominal ultrasound and laboratory investigation on hematological parameters), and evaluation of radiation exposure of participants (extracted from existing hospital records on their radiation exposure status). The participants were aged 20 to 65 years (mean = 34.04 ± 8.83), most of them were males (67.3%) and married (65.7%). Sixty five (59.1%) had good knowledge of radiation hazards, 58 (52.7%) had good knowledge of Personal Protective Devices (PPDs), less than a third, 30 (27.3%) consistently wore dosimeter, and very few (10.9% and below) consistently wore the various PPDs at work. The average annual radiation exposure over a 4 year period ranged from 0.0475mSv to 1.8725mSv. Only 1 (1.2%) of 86 participants had abnormal chest X-ray findings, 8 (9.4%) of 85 participants had abnormal abdominal ultrasound findings; while 17 (15.5%) and 11 (10.0%) of 110 participants had anemia and leucopenia respectively. This study demonstrated poor radiation protection practices despite good knowledge of radiation hazards among the participants, but radiation exposure and prevalence of abnormal clinical conditions were found to be low. Periodic in-service training and monitoring on radiation safety was suggested.

Applications of electromagnetic radiation in medicine

Recent decades have been devoted to the intense search for the response to questions related to the impact of radiation on the human body. Due to the growing fashion for a healthy lifestyle, increasing numbers of works about the alleged dangers of electromagnetic waves and diseases that they cause appeared. However, the discoveries of 20th century, and knowledge of the properties of electromagnetic radiation have allowed to broaden the horizons of the use of artificial sources of radiation in many fields of science and especially in medicine. The aim of this paper is to show that although excessive radiation or high doses are dangerous to the human body, its careful and controlled use, does not pose a threat, and it is often necessary in therapy. The possibility of using ionizing radiation in radiotherapy, isotope diagnostics or medical imaging, and non-ionizing radiation in the treatment for dermatological disorders and cancers will be presented. The unique properties of synchrotron radiation result in using it on a large scale in the diagnosis of pathological states by imaging methods.

Physical properties and biocompatibility of UHMWPE-derived materials modified by synchrotron radiation.

The applications of synchrotron radiation (SR) in medical imaging have become of great use, particularly in angiography, bronchography, mammography, computed tomography, and X-ray microscopy. Thanks to recently developed phase contrast imaging techniques non-destructive preclinical testing of low absorbing materials such as polymers has become possible. The focus of the present work is characterization and examination of UHMWPE-derived materials widely used in medicine, before and after their exposure to SR during such testing. Physical properties, such as wettability, surface energy, IR-spectroscopy, roughness, optical microscopy, microhardness measurements of UHMWPE samples were studied before and after SR. The relationship between a growth of UHMWPE surface hydrophilicity after SR and surface colonization by stromal cells was studied in vitro. Obtained results demonstrate that SR may be used as prospective direction to examine bulk (porous) structure of polymer materials and/or to modify polymer surface and volume for tissue engineering.

Medical imaging using ionizing radiation: Optimization of dose and image quality in fluoroscopy

The 2012 Summer School of the American Association of Physicists in Medicine (AAPM) focused on optimization of the use of ionizing radiation in medical imaging. Day 2 of the Summer School was devoted to fluoroscopy and interventional radiology and featured seven lectures. These lectures have been distilled into a single review paper covering equipment specification and siting, equipment acceptance testing and quality control, fluoroscope configuration, radiation effects, dose estimation and measurement, and principles of flat panel computed tomography. This review focuses on modern fluoroscopic equipment and is comprised in large part of information not found in textbooks on the subject. While this review does discuss technical aspects of modern fluoroscopic equipment, it focuses mainly on the clinical use and support of such equipment, from initial installation through estimation of patient dose and management of radiation effects. This review will be of interest to those learning about fluoroscopy, to those wishing to update their knowledge of modern fluoroscopic equipment, to those wishing to deepen their knowledge of particular topics, such as flat panel computed tomography, and to those who support fluoroscopic equipment in the clinic.

Current Opinions on Medical Radiation: A Survey of Oncologists Regarding Radiation Exposure and Dose Reduction in Oncology Patients

The aim of this study was to evaluate oncologists' opinions about the use of ionizing radiation in medical imaging of oncology patients. An electronic survey was e-mailed to 2,725 oncologists at the top 50 National Cancer Institute-funded cancer centers. The survey focused on opinions on CT dose reduction in oncology patients and current philosophies behind long-term imaging in these patients. The response rate was 15% (415 of 2,725). Eighty-two percent of respondents stated that their patients or families have expressed anxiety regarding radiation dose from medical imaging. Although fewer than half of oncologists (48%) did not know whether CT dose reduction techniques were used at their institutions, only 25% were concerned that small lesions may be missed with low-dose CT techniques. The majority of oncologists (63%) follow National Comprehensive Cancer Network guidelines for imaging follow-up, while the remainder follow other national guidelines such as those of the Children's Oncology Group, the American Society of Clinical Oncology, or clinical trials. Ninety percent of respondents believe that long-term surveillance in oncology patients is warranted, particularly in patients with breast cancer, melanoma, sarcoma, and pediatric malignancies. The majority of oncologists would consider the use of low-dose CT imaging in specific patient populations: (1) children and young women, (2) those with malignancies that do not routinely metastasize to the liver, and (3) patients undergoing surveillance imaging. Cumulative radiation exposure is a concern for patients and oncologists. Among oncologists, there is support for long-term imaging surveillance despite lack of national guidelines.

NCRP Report 160 and What It Means for Medical Imaging and Nuclear Medicine

The purpose of this paper is to briefly explain report 160 of the National Council on Radiation Protection and Measurement and the significance of the report to medical imaging as a whole and nuclear medicine specifically. The implications of the findings of report 160 have had repercussions and will continue to affect all of ionizing radiation medical imaging. The nuclear medicine community should have an understanding of why and how report 160 is important. After reading this article, the nuclear medicine technologist will be familiar with the main focus of report 160, the significant change that has occurred since the 1980s in the ionizing radiation exposure of people in the United States, the primary background source of ionizing radiation in the United States, the primary medical exposure to ionizing radiation in the United States, trends in nuclear medicine procedures and patient exposure, and a comparison of population doses between 2006 and the early 1980s as outlined in report 160.

Assessment of Patient Dose from CT Examinations in Khorasan, Iran

Introduction Computed Tomography scans are a very important tool for diagnosis and assessment of response to treatment in the practice of medicine. Ionizing radiation in medical imaging is undoubtedly one of the most powerful diagnostic tools in medicine. Yet, as with all medical interventions, there are potential risks in addition to the clear potential benefits. Materials and Methods Two reference dose quantities have been defined in order to promote the use of good technique in CT. These are weighted CT dose index (CTDIw) in (mGy) for a single slice in serial scanning or per rotation in helical scanning, and dose–length product (DLP) per complete examination (mGy.cm), All measurements were performed using a pencil shaped ionization chamber introduced into polymethyl methacrylate cylindrical brain and body phantoms. This survey was performed on 7 CT scanners in Khorasan Province-Iran. Results DLP for brain, chest, abdomen and pelvic examinations had a range of 255 - 1026, 76-1277, 48-737, 69-854 mGy.cm, respectively. Conclusion The results obtained in this study show that the DLP values obtained in this province are lower than European Commission reference dose levels (EC RDL), in other words performance of all the scanners were satisfactory.

Mapping very low level occupational exposure in medical imaging: A useful tool in risk communication and decision making

ObjectivesThe use of ionising radiation in medical imaging is accompanied with occupational exposure which should be limited by optimised room design and safety instructions. These measures can however not prevent that workers are exposed to instantaneous dose rates, e.g. the residual exposure through shielding or the exposure of discharged nuclear medicine patients. The latter elements are often questioned by workers and detailed assessment should give more information about the impact on the individual radiation dose. MethodsCumulated radiation exposure was measured in a university hospital during a period of 6 months by means of thermoluminescent dosimeters. Radiation exposure was measured at background locations and at locations where enhanced exposure levels are expected but where the impact on the individual exposure is unclear. ResultsThe results show a normal distribution of the cumulated background radiation level. No enhanced cumulated radiation exposure which significantly differs from this background level could be found during the operation of intra-oral apparatus, during ultrasonography procedures among nuclear medicine patients and at operator consoles of most CT-rooms. ConclusionsThis 6 months survey offers useful information about occupational low level exposure in medical imaging and the findings can be useful in both risk communication and decision making.

MPGD for breast cancer prevention: a high resolution and low dose radiation medical imaging

Early detection of small calcifications in mammograms is considered the best preventive tool of breast cancer. However, existing digital mammography with relatively low radiation skin exposure has limited accessibility and insufficient spatial resolution for small calcification detection. Micro Pattern Gaseous Detectors (MPGD) and associated technologies, increasingly provide new information useful to generate images of microscopic structures and make more accessible cutting edge technology for medical imaging and many other applications. In this work we foresee and develop an application for the new information provided by a MPGD camera in the form of highly controlled images with high dynamical resolution. We present a new Super Detail Image (S-DI) that efficiently profits of this new information provided by the MPGD camera to obtain very high spatial resolution images. Therefore, the method presented in this work shows that the MPGD camera with SD-I, can produce mammograms with the necessary spatial resolution to detect microcalcifications. It would substantially increase efficiency and accessibility of screening mammography to highly improve breast cancer prevention.

Is Ultrasound Imaging Inferior to Computed Tomography or Magnetic Resonance Imaging in Evaluating Renal Mass Size?

To evaluate whether ultrasonography was inferior in detecting the size of a renal mass preoperatively because of the increased attention on the harmful effects of ionizing radiation in medical imaging. A prospectively maintained database was reviewed of all patients who underwent renal ultrasonography before definitive therapy for the renal mass. Every patient who underwent ultrasound imaging also underwent computed tomography (CT) or magnetic resonance imaging (MRI), or both, before treatment. The size of the largest tumor identified per imaging modality was compared among the modalities using correlation and analysis of variance. A total of 116 patients underwent ultrasound imaging before therapy. Of these patients, 80 also underwent MRI, 66 underwent CT, and 38 underwent all 3 modalities before treatment. The average pathologic tumor size for the entire cohort was 4.45 cm (range 1-13). The size differences between CT and MRI compared with ultrasound were small (<3.5%). Compared with MRI and CT, ultrasound was also well correlated (P<.001 and P<.001). In patients who underwent all 3 imaging modalities, no difference was found in the average tumor size (P=.896). Ultrasound imaging does not appear to be inferior to CT and MRI in the imaging of renal masses. This is useful in reducing the costs and levels of radiation exposure for the long-term follow-up of patients receiving active surveillance.