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Impact of gonad shielding for AP pelvis on dose and image quality on different female sizes: A phantom study

Introduction: In clinical practice AP pelvis standard protocols are suitable for average size patients. However, as the average body size has increased over the past decades, radiographers have had to improve their practice in order to ensure that adequate image quality with minimal radiation dose to the patient is achieved. Gonad shielding has been found to be an effective way to reduce the radiation dose to the ovaries. However, the effect of increased body size, or fat thickness, in combination with gonad shielding is unclear. The goal of the study was to investigate the impact of gonad shielding in a phantom of adult female stature with increasing fat thicknesses on SNR (as a measure for image quality) and dose for AP pelvis examination. Methods: An adult Alderson female pelvis phantom was imaged with a variety of fat thickness categories as a representation of increasing BMI. 72 images were acquired using both AEC and manual exposure with and without gonad shielding. The radiation dose to the ovaries was measured using a MOSFET system. The relationship between fat thickness, SNR and dose when the AP pelvis was performed with and without shielding was investigated using the Wilcoxon signed rank test. P-values < 0.05 were considered to be statistically significant. Results: Ovary dose and SNR remained constant despite the use of gonad shielding while introducing fat layers. Conclusion: The ovary dose did not increase with an increase of fat thickness and the image quality was not altered. Implications for practice: Based on this phantom study it can be suggested that obese patients can expect the same image quality as average patients while respecting ALARA principle when using adequate protocols.

Factors associated with phantom limb pain

OBJECTIVE: To analyse the prevalence of phantom (limb) pain over time and to analyse factors associated with phantom (limb) pain in a prospective cohort of amputees.DESIGN: A multicentre longitudinal study.PATIENTS: One hundred and thirty-four patients scheduled for amputation were included.METHODS: Patients filled in questionnaires before amputation, and postal questionnaires six months, 1(1/2) years and 2(1/2) years to a maximum of 3(1/2) years after amputation. Preoperative assessment included patients' characteristics, date, side and level of, and reason for amputation. The follow-up questionnaires assessed the frequencies of the experienced phantom pain, prosthetic use and walking distance. The occurrence of phantom pain was defined as phantom pain a few times a day or more frequently.RESULTS: Pre- and postoperative questionnaires were available filled in by 85 amputees (33 females and 52 males). The percentage of lower limb amputees with phantom pain was the highest at six months after amputation, and of upper limb amputees at 1(1/2) years. In general, more women than men experienced phantom pain. One and a half years and 2(1/2) years after amputation the highest percentages of the lower limb amputees used their prosthesis more than 4 hours a day (66%), after that time this percentage decreased to 60%. The results of the two-level logistic regression analysis to predict phantom pain show that phantom pain was less frequently present in men (odds ratio (OR) = 0.12), in lower limb amputees (OR = 0.14) and that it decreased in due course (OR = 0.53 for 1 year).CONCLUSION: Protective factors for phantom pain are: being male, having a lower limb amputation and the time elapsed since amputation.

Lesion detection performance

Incidental findings on low-dose CT images obtained during hybrid imaging are an increasing phenomenon as CT technology advances. Understanding the diagnostic value of incidental findings along with the technical limitations is important when reporting image results and recommending follow-up, which may result in an additional radiation dose from further diagnostic imaging and an increase in patient anxiety. This study assessed lesions incidentally detected on CT images acquired for attenuation correction on two SPECT/CT systems.METHODS: An anthropomorphic chest phantom containing simulated lesions of varying size and density was imaged on an Infinia Hawkeye 4 and a Symbia T6 using the low-dose CT settings applied for attenuation correction acquisitions in myocardial perfusion imaging. Twenty-two interpreters assessed 46 images from each SPECT/CT system (15 normal images and 31 abnormal images; 41 lesions). Data were evaluated using a jackknife alternative free-response receiver-operating-characteristic analysis (JAFROC).RESULTS: JAFROC analysis showed a significant difference (P < 0.0001) in lesion detection, with the figures of merit being 0.599 (95% confidence interval, 0.568, 0.631) and 0.810 (95% confidence interval, 0.781, 0.839) for the Infinia Hawkeye 4 and Symbia T6, respectively. Lesion detection on the Infinia Hawkeye 4 was generally limited to larger, higher-density lesions. The Symbia T6 allowed improved detection rates for midsized lesions and some lower-density lesions. However, interpreters struggled to detect small (5 mm) lesions on both image sets, irrespective of density.CONCLUSION: Lesion detection is more reliable on low-dose CT images from the Symbia T6 than from the Infinia Hawkeye 4. This phantom-based study gives an indication of potential lesion detection in the clinical context as shown by two commonly used SPECT/CT systems, which may assist the clinician in determining whether further diagnostic imaging is justified.

Treating phantom limb pain following amputation

Phantom limb pain following amputation is highly prevalent as it affects up to 80% of amputees. Many amputees suffer from phantom limb pain for many years and experience major limitations in daily routines and quality of life. Conventional pharmacological interventions often have negative side-effects and evidence regarding their long-term efficacy is low. Central malplasticity such as the invasion of areas neighbouring the cortical representation of the amputated limb contributes to the occurrence and maintenance of phantom limb pain. In this context, alternative, non-pharmacological interventions such as mirror therapy that are thought to target these central mechanisms have gained increasing attention in the treatment of phantom limb pain. However, a standardized evidence-based treatment protocol for mirror therapy in patients with phantom limb pain is lacking, and evidence for its effectiveness is still low. Furthermore, given the chronic nature of phantom limb pain and suggested central malplasticity, published studies proposed that patients should self-deliver mirror therapy over several weeks to months to achieve sustainable effects. To achieve this training intensity, patients need to perform self-delivered exercises on a regular basis, which could be facilitated though the use of information and communication technology such as telerehabilitation. However, little is known about potential benefits of using telerehabilitation in patients with phantom limb pain, and controlled clinical trials investigating effects are lacking. The present thesis presents the findings from the ‘PAtient Centered Telerehabilitation’ (PACT) project, which was conducted in three consecutive phases: 1) creating a theoretical foundation; 2) modelling the intervention; and 3) evaluating the intervention in clinical practice. The objectives formulated for the three phases of the PACT project were: 1) to conduct a systematic review of the literature regarding important clinical aspects of mirror therapy. It focused on the evidence of applying mirror therapy in patients with stroke, complex regional pain syndrome and phantom limb pain. 2) to design and develop a clinical framework and a user-centred telerehabilitation for mirror therapy in patients with phantom limb pain following lower limb amputation. 3) to evaluate the effects of the clinical framework for mirror therapy and the additional effects of the teletreatment in patients with phantom limb pain. It also investigated whether the interventions were delivered by patients and therapists as intended.

OPTIMAX 2017 Radiation dose, image quality optimisation, the use of new technology in medical imaging

The validity and reliability of the exposure index as a metric for estimating the radiation dose to the patient

INTRODUCTION: With the introduction of digital radiography, the feedback between image quality and over-exposure has been partly lost which in some cases has led to a steady increase in dose. Over the years the introduction of exposure index (EI) has been used to resolve this phenomenon referred to as 'dose creep'. Even though EI is often vendor specific it is always a related of the radiation exposure to the detector. Due to the nature of this relationship EI can also be used as a patient dose indicator, however this is not widely investigated in literature.METHODS: A total of 420 dose-area-product (DAP) and EI measurements were taken whilst varying kVp, mAs and body habitus on two different anthropomorphic phantoms (pelvis and chest). Using linear regression, the correlation between EI and DAP were examined. Additionally, two separate region of interest (ROI) placements/per phantom where examined in order to research any effect on EI.RESULTS: When dividing the data into subsets, a strong correlation between EI and DAP was shown with all R-squared values > 0.987. Comparison between the ROI placements showed a significant difference between EIs for both placements.CONCLUSION: This research shows a clear relationship between EI and radiation dose which is dependent on a wide variety of factors such as ROI placement, body habitus. In addition, pathology and manufacturer specific EI's are likely to be of influence as well.IMPLICATIONS FOR PRACTICE: The combination of DAP and EI might be used as a patient dose indicator. However, the influencing factors as mentioned in the conclusion should be considered and examined before implementation.