Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

PURPOSE: To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. MATERIALS AND METHODS: A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. RESULTS: Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. CONCLUSIONS: Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

Optimizing the balance between radiation dose and image quality in pediatric head CT: findings before and after intensive radiologic staff training.

OBJECTIVE: The purpose of this study was to assess the radiation dose and image quality of pediatric head CT examinations before and after radiologic staff training. MATERIALS AND METHODS: Outpatients 1 month to 14 years old underwent 215 unenhanced head CT examinations before and after intensive training of staff radiologists and technologists in optimization of CT technique. Patients were divided into three age groups (0-4, 5-9, and 10-14 years), and CT dose index, dose-length product, tube voltage, and tube current-rotation time product values before and after training were retrieved from the hospital PACS. Gray matter conspicuity and contrast-to-noise ratio before and after training were calculated, and subjective image quality in terms of artifacts, gray-white matter differentiation, noise, visualization of posterior fossa structures, and need for repeat CT examination was visually evaluated by three neuroradiologists. RESULTS: The median CT dose index and dose-length product values were significantly lower after than before training in all age groups (27 mGy and 338 mGy ∙ cm vs 107 mGy and 1444 mGy ∙ cm in the 0- to 4-year-old group, 41 mGy and 483 mGy ∙ cm vs 68 mGy and 976 mGy ∙ cm in the 5- to 9-year-old group, and 51 mGy and 679 mGy ∙ cm vs 107 mGy and 1480 mGy ∙ cm in the 10- to 14-year-old group; p < 0.001). The tube voltage and tube current-time values after training were significantly lower than the levels before training (p < 0.001). Subjective posttraining image quality was not inferior to pretraining levels for any item except noise (p < 0.05), which, however, was never diagnostically unacceptable. CONCLUSION: Radiologic staff training can be effective in reducing radiation dose while preserving diagnostic image quality in pediatric head CT examinations.

A comprehensive assessment of physical image quality of five different scanners for head CT imaging as clinically used at a single hospital centre-A phantom study.

Nowadays, given the technological advance in CT imaging and increasing heterogeneity in characteristics of CT scanners, a number of CT scanners with different manufacturers/technologies are often installed in a hospital centre and used by various departments. In this phantom study, a comprehensive assessment of image quality of 5 scanners (from 3 manufacturers and with different models) for head CT imaging, as clinically used at a single hospital centre, was hence carried out. Helical and/or sequential acquisitions of the Catphan-504 phantom were performed, using the scanning protocols (CTDIvol range: 54.7-57.5 mGy) employed by the staff of various Radiology/Neuroradiology departments of our institution for routine head examinations. CT image quality for each scanner/acquisition protocol was assessed through noise level, noise power spectrum (NPS), contrast-to-noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD) and non-uniformity index analyses. Noise values ranged from 3.5 HU to 5.7 HU across scanners/acquisition protocols. NPS curves differed in terms of peak position (range: 0.21-0.30 mm-1). A substantial variation of CNR values with scanner/acquisition protocol was observed for different contrast inserts. The coefficient of variation (standard deviation divided by mean value) of CNR values across scanners/acquisition protocols was 18.3%, 31.4%, 34.2%, 30.4% and 30% for teflon, delrin, LDPE, polystyrene and acrylic insert, respectively. An appreciable difference in MTF curves across scanners/acquisition protocols was revealed, with a coefficient of variation of f50%/f10% of MTF curves across scanners/acquisition protocols of 10.1%/7.4%. A relevant difference in LCD performance of different scanners/acquisition protocols was found. The range of contrast threshold for a typical object size of 3 mm was 3.7-5.8 HU. Moreover, appreciable differences in terms of NUI values (range: 4.1%-8.3%) were found. The analysis of several quality indices showed a non-negligible variability in head CT imaging capabilities across different scanners/acquisition protocols. This highlights the importance of a physical in-depth characterization of image quality for each CT scanner as clinically used, in order to optimize CT imaging procedures.

Patient Perceptions and Knowledge of Ionizing Radiation From Medical Imaging.

Importance: Although imaging has become a standard tool of modern medicine, its widespread use has been paralleled by an increasing cumulative radiation dose to patients despite technological advancements and campaigns calling for better awareness and minimization of unnecessary exposures. Objective: To assess patients' knowledge about medical radiation and related risks. Design, Setting, and Participants: A survey study of hospitals in Italy was conducted; all patients in waiting rooms for medical imaging procedures before undergoing imaging examinations at 16 teaching and nonteaching hospitals were approached to take the survey. The survey was performed from June 1, 2019, to May 31, 2020. Main Outcomes and Measures: Survey respondents' basic knowledge of ionizing radiation levels and health risks, earlier imaging tests performed, and information and communication about radiation protection issues. Results: Among 3039 patients invited to participate, the response rate was 94.3% (n = 2866). Participants included 1531 women (53.4%); mean (SD) age was 44.9 (17.3) years. Of the 2866 participants, 1529 (53.3%) were aware of the existence of natural sources of ionizing radiation. Mammography (1101 [38.4%]) and magnetic resonance imaging (1231 [43.0%]) were categorized as radiation-based imaging modalities. More than half of the 2866 patients (1579 [55.1%]; P = .03) did not know that chest computed tomography delivers a larger dose of radiation than chest radiography, and only 1499 (52.3%) knew that radiation can be emitted after nuclear medicine examinations (P = .004). A total of 667 patients (23.3%) believed that radiation risks were unrelated to age, 1273 (44.4%) deemed their knowledge about radiation risks inadequate, and 2305 (80.4%) preferred to be informed about radiation risks by medical staff. A better knowledge of radiation issues was associated with receiving information from health care professionals (odds ratio [OR], 1.71; 95% CI, 1.43-2.03; P < .001) and having a higher educational level (intermediate vs low: OR, 1.48; 95% CI, 1.17-1.88; P < .001; high vs low: OR, 2.68; 95% CI, 2.09-3.43; P < .001). Conclusions and Relevance: The results of this survey suggest that patients undergoing medical imaging procedures have overall limited knowledge about medical radiation. Intervention to achieve better patient awareness of radiation risks related to medical exposures may be beneficial.

CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden.

Our aim is to compare the radiation dose associated with a low-dose CT colonography (CTC) protocol for colorectal cancer screening with that delivered by double-contrast barium enema (DCBE). CTC of twenty asymptomatic individuals (M:F = 10:10) participating to a colorectal cancer screening program and DCBE of fifteen patients (M:F = 6:9) were evaluated. For CTC, absorbed dose was determined by calculating the dose-length product for each CTC examination from measurements on a CT dose phantom equipped with a CT ion chamber. For DCBE, the free-in-air Kerma at the patient's X-ray entry surface and the Kerma-area product during fluoroscopy and fluorography were measured with a Barracuda system, with fluoroscopy times being recorded blinded to the performing operator. Effective dose at CTC was 2.17 ± 0.12 mSv, with good and excellent image quality in 14/20 (70%) and 6/20 cases (30%), respectively. With DCBE, effective patient dose was 4.12 ± 0.17 mSv, 1.9 times greater than CTC (P < 0.0001). Our results show that effective dose from screening CTC is substantially lower than that from DCBE, suggesting that CTC is the radiological imaging technique of the large bowel with the lowest risk of stochastic radiation effects.

Effect of CT Localizer Radiographs on Radiation Dose Associated With Automatic Tube Current Modulation: A Multivendor Study.

OBJECTIVES: To assess the influence of the CT localizer radiograph on the automatic tube current modulation system of 7 CT scanners produced by 4 different CT manufacturers. METHODS: The influence of the localizer orientation, table height, tube current and tube potential values on the radiation dose of the related CT scan were evaluated. Images were acquired by using an anthropomorphic phantom positioned in the CT gantry isocenter as well as from -6 cm to +6 cm vertically to the isocenter. RESULTS: Vertical movement of the CT table height affected the radiation dose in all scanners using anterior-posterior or a posterior-anterior localizer orientation albeit differently, depending on the manufacturer; only in 1/7 scanner no influence was observed. The latero-lateral localizer orientation proved to be more effective in limiting the influence of the vertical miscentering in all scanners. Changing localizer's tube voltage influenced the scan radiation dose in scanners produced by two manufacturers, while no significant effect was observed in scanners produced by the other two manufacturers. No significant dose variation was observed in 6/7 scanners when changing the localizer's tube current. CONCLUSION: Localizer radiograph shows a significant influence on the radiation exposure but with different outcomes depending on the manufacturer of the CT scanner. Radiologists and radiographers should have a thorough understanding of these differences to assure patients the best examination in terms of radiation dose and image quality.

The AISPEP (Associazione Italiana Sindromi Pelvico Prostatiche) chronic prostatitis questionnaire (AISPEP-Q). focus on the disease: anamnestic data, life activities, symptoms, sexual habits, quality of life and knowledge about prostatitis from 93 questions answered on the Internet.

Chronic prostatitis (CP) has been described as one of the most common illnesses men aged < or = 50, showing a significant impact on patients' quality of life comparable with other chronic diseases, such as unstable angina or Crohn's disease. CP also is a social and economic problem due to its high incidence in the young male population and to the absence of evidence for the effectiveness of treatment. Today, however, although validated outcome questionnaires are available to follow prostatitis patients, diagnostic and treatment options are based on experience, expert opinion and poor clinical trial data. More extensive and better-designed epidemiological studies are needed to evaluate and describe prostatitis patient clinical characteristics, in order to carry out correct and useful treatment. The aim of this report is to present the new Associazione Italiana Sindromi Pelvico Prostatiche questionnaire (AISPEP-Q) in order to provide a tool for increasing knowledge in prostatitis patient characteristics and design future epidemiological studies.

Awareness of radiation protection and dose levels of imaging procedures among medical students, radiography students, and radiology residents at an academic hospital: Results of a comprehensive survey.

PURPOSE: To evaluate the awareness of radiation protection issues and the knowledge of dose levels of imaging procedures among medical students, radiology residents, and radiography students at an academic hospital. MATERIAL AND METHODS: A total of 159 young doctors and students (including 60 radiology residents, 56 medical students, and 43 radiography students) were issued a questionnaire consisting of 16 multiple choice questions divided into three separated sections (i.e., demographic data, awareness about radiation protection issues, and knowledge about radiation dose levels of common radiological examinations). RESULTS: Medical students claimed to have at least a good knowledge of radiation protection issues more frequently than radiology residents and radiography students (94.4% vs 55% and 35.7%, respectively; P<0.05), with no cases of perceived excellent knowledge among radiography students. However, the actual knowledge of essential radiation protection topics such as regulations, patient and tissue susceptibility to radiation damage, professional radiation risk and dose optimisation, as well as of radiation doses delivered by common radiological procedures was significantly worse among medical students than radiology residents and radiography students (P<0.05). Those latter significantly outperformed radiology residents as to knowledge of radiation protection issues (P<0.01). Overall, less than 50% of survey respondents correctly answered all questions of the survey. CONCLUSIONS: Radiology residents, radiography students and medical students have a limited awareness about radiation protection, with a specific gap of knowledge concerning real radiation doses of daily radiological examinations. Both undergraduate and postgraduate teaching needs to be effectively implemented with radiation safety courses.

Automated contrast medium monitoring system for computed tomography--Intra-institutional audit.

The aim of this study was to analyze the usage and the data recorded by a RIS-PACS-connected contrast medium (CM) monitoring system (Certegra(®), Bayer Healthcare, Leverkusen, Germany) over 19 months of CT activity. The system used was connected to two dual syringe power injectors (each associated with a 16-row and a high definition 64-row multidetector CT scanner, respectively), allowing to manage contrast medium injection parameters and to send and retrieve CT study-related information via RIS/PACS for any scheduled contrast-enhanced CT examination. The system can handle up to 64 variables and can be accessed via touchscreen by CT operators as well as via a web interface by registered users with three different hierarchy levels. Data related to CM injection parameters (i.e. iodine concentration, volume and flow rate of CM, iodine delivery rate and iodine dose, CM injection pressure, and volume and flow rate of saline), patient weight and height, and type of CT study over a testing period spanning from 1 June 2013 to 10 January 2015 were retrieved from the system. Technical alerts occurred for each injection event (such as system disarm due to technical failure, disarm due to operator's stop, incomplete filling of patient data fields, or excessively high injection pressure), as well as interoperability issues related to data sending and receiving to/from the RIS/PACS were also recorded. During the testing period, the CM monitoring system generated a total of 8609 reports, of which 7629 relative to successful injection events (88.6%). 331 alerts were generated, of which 40 resulted in injection interruption and 291 in CM flow rate limitation due to excessively high injection pressure (>325 psi). Average CM volume and flow rate were 93.73 ± 17.58 mL and 3.53 ± 0.89 mL/s, and contrast injection pressure ranged between 5 and 167 psi. A statistically significant correlation was found between iodine concentration and peak IDR (rs=0.2744, p<0.0001), as well as between iodine concentration and iodine dose (rs=0.3862, p<0.0001) for all CT studies. Automated contrast management systems can provide a full report of contrast use with the possibility to systematically compare different contrast injection protocols, minimize errors, and optimize organ-specific contrast enhancement for any given patient and clinical application. This can be useful to improve and harmonize the quality and consistency of contrast CT procedures within the same radiological department and across the hospital, as well as to monitor potential adverse events and overall costs.

Effect of clinorotation on in vitro cultured explants of Mentha piperita L.

An in vitro culture system was used to study the influence of gravity on axillary shoot formation and adventitious root regeneration in Mentha piperita L. The direction of the gravity vector was altered by displacing stem node explants in different orientations. Also, microgravity conditions were simulated by rotating the explants on a horizontal clinostat so that the main axis of nodes was either parallel (Cpa) or perpendicular to the clinostat axis (Ccp and Ccf, centripetally and centrifugally oriented, respectively). Mint nodes were cultured on solidified Linsmaier and Skoog's medium [Physiol. Plant. 18 (1965) 100] adding a filter-sterilized aqueous solution of 2 mg/l benzyladenine (BA) in half of the cultures. The proliferation of axillary shoots as well as adventitious root formation were not affected by altering upright explant orientation. On the contrary clinorotation was able to modify plantlet development. In absence of BA, leaf width was hindered by Cpa treatment and penultimate internode length was enhanced by Ccp. Furthermore, a negative effect of Cpa treatment was observed in root length parameter, while Ccp increased the root number both in absence and in presence of BA. An effect strictly connected to clinorotation in presence of BA was the occurrence of hyperhydricity. Moreover, explants under clinorotation treatments switched their gravitropic response modifying shoot curvature.

Real practice radiation dose and dosimetric impact of radiological staff training in body CT examinations.

OBJECTIVES: To evaluate the radiation dose of the main body CT examinations performed routinely in four regional diagnostic centres, the specific contribution of radiologists and technologists in determining CT dose levels, and the role of radiological staff training in reducing radiation doses. METHODS: We retrospectively evaluated the radiation dose in terms of dose-length product (DLP) values of 2,016 adult CT examinations (chest, abdomen-pelvis, and whole body) collected in four different centres in our region. DLP values for contrast-unenhanced and contrast-enhanced CT examinations performed at each centre were compared for each anatomical area. DLP values for CT examinations performed before and after radiological staff training were also compared. RESULTS: DLP values for the same CT examinations varied among centres depending on radiologists' preferences, variable training of technologists, and diversified CT image acquisition protocols. A specific training programme designed for the radiological staff led to a significant overall reduction of DLP values, along with a significant reduction of DLP variability. CONCLUSIONS: Training of both radiologists and technologists plays a key role in optimising CT acquisition procedures and lowering the radiation dose delivered to patients. MAIN MESSAGES: • The effective dose for similar CT examinations varies significantly among radiological centres. • Staff training can significantly reduce and harmonise the radiation dose. • Training of radiologists and technologists is key to optimise CT acquisition protocols.

Are retinal and retinal-binding proteins involved in stomatal response to blue light?

Stomata respond to blue light and it is generally believed that the photoreceptor for this response is located inside the guard cells. Only a small number of blue light photoreceptors have been identified so far, namely cryptochromes and phototropins, and they show overlapping functions in regulating many different responses to light. The possibility that plants may possess other receptors regulating blue light responses under different light conditions cannot be excluded. In this paper we show the presence of two retinal-binding proteins in Commelina communis and we report the identification of retinal, a chromophore usually bound to the photoreceptor rhodopsin and previously identified in algae and other higher plants. We show that, under our experimental conditions, stomata open promptly when exposed to blue light and we demonstrated that this response is dependent on retinal. We hypothesise that rhodopsin-like retinal-binding proteins might be involved in stomatal response to blue light.

A turanose-insensitive mutant suggests a role for WOX5 in auxin homeostasis in Arabidopsis thaliana.

Sugars acting as signalling molecules regulate many developmental processes in plants, including lateral and adventitious root production. Turanose, a non-metabolizable sucrose analogue, profoundly affects the growth pattern of Arabidopsis seedlings. Turanose-treated seedlings are characterized by a very short primary root and a short hypocotyl showing the production of adventitious roots. A turanose-insensitive (tin) mutant was identified and characterized. Because of a T-DNA insertion and a chromosomal translocation, tin expresses a chimeric form of WOX5, a gene known to be expressed in the root quiescent centre. The tin mutation can be complemented by overexpression of WOX5, suggesting it is a loss-of-function mutant. We found that WOX5 is both turanose- and auxin-inducible. Moreover, turanose insensitivity is associated with altered auxin homeostasis, as demonstrated by the constitutive activation of indole acetic acid (IAA) conjugation and SUPERROOT2 expression in tin. On the basis of turanose effects on wild-type seedlings and the tin molecular and hormonal phenotype, we propose a role for WOX5 in the root apical meristem as a negative trigger of IAA homeostatic mechanisms allowing the maintenance of a restricted area of auxin maximum, which is required for a correct root-formation pattern.

Expression of two genes encoding gibberellin 2- and 3-oxidases in developing seeds of Phaseolus coccineus.

We have isolated PcGA3ox1, a cDNA clone from developing runner bean (Phaseolus coccineus) seeds that shows significant amino acid homology with the gibberellin (GA) 3-oxidases. A recombinant fusion protein of PcGA3ox1 converted GA20 and GA9 to GA1 and GA4, respectively. In situ hybridization results showed that transcripts of this gene accumulate specifically within the suspensor of globular-stage embryos. PcGA3ox1 mRNA begins to accumulate in the epidermal cells of the embryo proper and is also detectable in the endosperm during the transition from globular- to heart-stage embryos. PcGA3ox1 transcripts were localized exclusively in the cotyledons from the early cotyledonary stage up to the cotyledonary stage. Transcripts of the previously cloned GA 2-oxidase (PcGA2ox1) from developing seeds of runner bean were found primarily within the suspensor neck region from the late globular stage up to the heart stage. PcGA2ox1 mRNA was detectable in the whole suspensor from the early cotyledonary stage, and was found in the inner layer of integuments at the cotyledonary stage. Soluble enzyme preparations made from suspensors and embryos at two stages of embryogenesis (the heart and cotyledonary stages) were incubated with [14C]GA20 and [14C]GA1. Only young suspensor preparations converted GA20 to GA1 and GA5. Both suspensor preparations converted GA1 to GA8. Both embryo preparations converted GA20 to GA1, but were unable to convert GA1 to GA8.