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British Journal of Radiology [journal]
- In vivo dosimetry: trends and prospects for brachytherapy. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 8.:20140206.
The error types during brachytherapy (BT) treatments and their occurrence rates are not well known. The limited knowledge is partly attributed to the lack of independent verification systems of the treatment progression in the clinical workflow routine. Within the field of in vivo dosimetry (IVD), it is established that real-time IVD can provide efficient error detection and treatment verification. However, it is also recognized that widespread implementations are hampered by the lack of available high-accuracy IVD systems that are straightforward for the clinical staff to use. This article highlights the capabilities of the state-of-the-art IVD technology in the context of error detection and quality assurance (QA) and discusses related prospects of the latest developments within the field. The article emphasizes the main challenges responsible for the limited practice of IVD and provides descriptions on how they can be overcome. Finally, the article suggests a framework for collaborations between BT clinics that implemented IVD on a routine basis and postulates that such collaborations could improve BT QA measures and the knowledge about BT error types and their occurrence rates.
- Non osseous incidental findings in low dose whole body CT in patients with multiple myeloma. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 9.:20140185.
Objective: The purpose of this study was to identify the frequency and grading of non osseous incidental findings (NOIF) in non contrast whole body low dose CT (LDCT) in patients with multiple myeloma. Methods: In the time period from 2010 to 2013, 93 patients with multiple myeloma were staged by non contrast whole body LDCT at our radiological department. LDCT images were analyzed retrospectively for NOIF, which also included unsuspected extramedullary manifestation of multiple myeloma. All NOIF were classified as major or clinically significant, moderate or possibly clinically significant, and minor or not clinically significant. Medical records were analyzed regarding further investigation and follow-up of the identified NOIF. Results: In the 93 patients, 295 NOIF were identified (on average 3.2 NOIF per patient). Most of the NOIF (52.4%) were not clinically significant, 25.8% of the NOIF were possibly clinically significant, and 21.8% of the NOIF were clinically significant. Clinically significant NOIF were investigated further by CT after intravenous administration of contrast medium and/or by ultrasound or magnetic resonance imaging. In 34 of these cases, extramedullary relapse of myeloma, occult carcinoma or infectious/septic incidental findings were diagnosed (11.5% of all NOIF). In the remaining 10.3% of the NOIF classified as clinically significant, various benign lesions were diagnosed. Conclusion: LDCT detected various non osseous lesions in patients with multiple myeloma. 36.6% of the patients had clinically significant NOIF. These findings underline the importance to check LDCT examinations in patients with multiple myeloma carefully for the presence of NOIF.
- Pyogenic and Nonpyogenic Spinal Infections: Emphasis on Diffusion-Weighted Imaging for the Detection of Abscesses and Pus Collections. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 7.:20140011.
The incidence of spinal infections has increased in the past two decades, due to increasing number of elderly patients, immunocompromised conditions, spinal surgery and instrumentation, vascular access and intravenous drug use. Conventional magnetic resonance imaging (MRI) is the gold standard for diagnostic imaging; however, there are still a significant number of misdiagnosed cases. Diffusion-weighted imaging (DWI) with b-value of 1000 and ADC (apparent diffusion coefficient) maps provide early and accurate detection of abscess and pus collection. Pyogenic infections are classified into 4 types of the extension based on MRI and DWI findings: 1) Epidural/ paraspinal abscess with spondylodiskitis, 2) Epidural/paraspinal abscess with facet joint infection, 3) Epidural/paraspinal abscess without concomitant spondylodiscitis or facet joint infection, and 4) Intradural abscess (subdural abscess, purulent meningitis and spinal cord abscess). DWI easily detects abscesses and demonstrates the extension, multiplicity, and remote disseminated infection. DWI is often a key image in the differential diagnosis. Important differential diagnoses include epidural subdural or subarachnoid hemorrhage, CSF leak, disc herniation, synovial cyst, granulation tissue, intra- or extradural tumor, and postsurgical fluid collections. DWI and the ADC value are affected by susceptibility artifacts, incomplete fat suppression, and volume-averaging artifacts. Recognition of artifacts is essential when interpreting DWI of spinal and paraspinal infections. DWI is not only useful for the diagnosis but also the treatment planning of pyogenic and non-pyogenic spinal infections.
- Comparison of Effective Dose and Lifetime Risk of Cancer Incidence of Computed Tomography Attenuation Correction Acquisitions and Radiopharmaceutical Administration for Myocardial Perfusion Imaging. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 7.:20140110.
Objectives: To measure the organ dose and calculate effective dose from CTAC acquisitions from protocols based on four commonly used gamma camera SPECT/CT systems. Method: CTAC dosimetry data was collected using thermoluminescent dosimeters on GE's Infinia Hawkeye four and single slice systems, Siemen's Symbia T6 and the Philips Precedence. Organ and effective dose from the administration of (99m)Tc-tetrofosmin and (99m)Tc-sestamibi were calculated using ICRP reports 80 and 106. Using this data the lifetime biological risk was calculated. Results: The Siemens Symbia gave the lowest CTAC dose (1.8 mSv) followed by the GE Infinia Hawkeye single-slice (1.9 mSv), GE Infinia Hawkeye four-slice (2.5 mSv) and Philips Precedence (3.0). Doses were significantly lower than the calculated doses from radiopharmaceutical administration (11 mSv and 14 mSv for 99m Tc-Tetrofosmin and 99m Tc-Sestamibi respectively). Overall lifetime biological risks were lower suggesting that using CTAC data posed minimal risk to the patient. Comparison of data for breast tissue demonstrated a higher risk than that from the radiopharmaceutical. Conclusions: CTAC doses were confirmed to be much lower than from radiopharmaceutical administration and diagnostic CT chest examinations. However risk to breast tissue was significantly higher than that arising from the radiopharmaceutical administration. Advances in knowledge: This research proved that CTAC is a comparatively low dose procedure. However, it has been shown that there is increased risk to breast tissue especially in the younger patient. As per legislation justification is required and CTAC should only be used in situations that demonstrate sufficient net benefit.
- Exploring silver as a contrast agent for contrast-enhanced dual-energy x-ray breast imaging. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 7.:20140081.
Objectives: Through prior monoenergetic modeling, we have identified silver as a potential alternative to iodine in dual-energy (DE) x-ray breast imaging. The purpose of this study is to compare the performance of silver and iodine contrast agents in a commercially-available DE imaging system through a quantitative analysis of signal difference-to-noise ratio (SDNR). Methods: A polyenergetic simulation algorithm was developed to model the signal intensity and noise. The model identified the influence of various technique parameters on SDNR. The model was also used to identify the optimal imaging techniques for silver and iodine, so that the two contrast materials could be objectively compared. Results: The major influences on the SDNR were the low-energy dose fraction and breast thickness. An increase in the value of either of these parameters resulted in a decrease in SDNR. The SDNR for silver was, on average 43% higher than iodine when imaged at their respective optimal conditions, and 40% higher when both were imaged at the optimal conditions for iodine. Conclusions: A silver contrast agent should provide benefit over iodine, even when translated to the clinic without modification of imaging system or protocol. If the system were slightly modified to reflect the lower k-edge of silver, the difference in SDNR between the two materials would be increased. Advances in knowledge: These data are the first to demonstrate the suitability of silver as a contrast material in a clinical CEDE image acquisition system.
- The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 3.:20140134.
A new efficient type of gadolinium-based theranostic agent (AGuIX) has recently been developed for magnetic resonance imaging (MRI)-guided radiotherapy. These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Due to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, while a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, these particles present no evidence of toxicity, in the absence of irradiation with up to 10 times the planned dose for clinical trials. AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies, and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Preclinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intra-tumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a radiotherapy protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed.
- The imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumors (pPNETs). [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 2.:20130631.
Objective: To explore the imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumors (pPNETs). Methods: The imaging features and pathological characteristics of eight cases of surgically and pathologically confirmed Ewing sarcoma/pPNET were analyzed retrospectively in light of recent literature on the disease. Results: The peak age was between 10 and 20. The lesions tended to be spindle-shaped and dural-based, usually widely so. CT showed the lesions were slightly uneven high density in 5 cases, iso-low mixed density in 3 cases; marked heterogeneous enhancement was seen in all cases after contrast injection. Magnetic resonance imaging of the lesions showed varying proportions of isointense and hypointense signal in all cases on unenhanced T1-weighted imaging, and varying proportions of isointense and hyperintense signal on T2-weighted imaging. After contrast injection, marked heterogeneous enhancement was seen in all cases; three cases showed a short and nodular dural tail and five cases showed adjacent skull erosion and osteolysis. Pathological results included high cell density, hemorrhage, and necrosis. The cells resembled lymphocytes and spindle cells with transparent cytoplasm. CD99 and vimentin were expressed by all tumor cells. Conclusion: Features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumors (pPNETs) include peak incidence in the second decade, a broad connection to the meninges, a thick dural tail involved with tumor, skull and scalp erosion, and early metastasis. Necrosis and cystic changes are common histological findings. Advances in knowledge: The imaging features of meningeal Ewing sarcoma/pPNETs have not been reported. The study helps to identify meningeal Ewing sarcoma/pPNETs and meningioma.
- Extragonadal Teratomas of the Adult Abdomen and Pelvis: A Pictorial Review. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 1.:20140116.
Teratomas comprise a spectrum of tumours that have striking imaging appearances and are commonly considered when evaluating a mass in the female pelvis. A subgroup of these tumours located in an extragonadal abdomino-pelvic location, in contrast are extremely rare, and can affect both sexes. Extra gonadal teratomas can occur at all ages, are particularly unusual in adults and can cause confusion in the differential diagnosis, especially in children. Familiarity with the imaging features of the spectrum of teratomas within the abdominal cavity is therefore of great importance, as radiological diagnosis can guide treatment, preventing delays in diagnosis and avoidable sequelae. This article summarizes the radiological appearances of these rare extragonadal tumours in adults in relation to their pathology, malignant potential, location and behaviour. Although uncommon, teratomas should be considered in the differential diagnosis of extragonadal abdominal masses, particularly in young adults.
- Additional diagnostic value of magnetic resonance imaging in patients with suspicious breast lesions based on ultrasound. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 1.:20140009.
Objectives: Biopsy has long been the standard approach in BIRADS 4 or BIRADS 5 lesions despite a wide variation in reported incidence of malignancy in BIRADS 4 lesions. This study examined the diagnostic value of breast MRI as well as its ability to decrease unnecessary biopsies in patients with solid breast lesions who had an indication for biopsy. Methods: In this retrospective study, 277 female breast lesions with a documented histological diagnosis as established by ultrasound-guided biopsy were included. Biopsies were performed due to a BIRADS score 4/5 on ultrasonography. In addition, all patients had undergone MRI before biopsy. Diagnostic value of MRI was calculated for the prediction of malignancy. Results: Overall sensitivity, specificity, negative predictive value, and positive predictive value of MRI in detecting malignancy were 94.2%, 56.1%, 90.7%, and 68.1%, respectively. When only ultrasonographically BIRADS 4 lesions are considered, corresponding figures were as follows: 90.9%, 56.7%, 93.8%, and 46.4%, respectively. False-negative rate of MRI for the latter group of lesions was 2.6%. Forty-two percent of unnecessary biopsies were avoided in sonographically BIRADS 4 lesions. Conclusions: Despite promising results obtained in this study, currently dynamic MRI does not seem to be effective in ruling out the need for biopsy in the assessment of sonographically BIRADS 4 lesions. Advances in knowledge: In the future, MRI may decrease the number of unnecessary biopsies in patients with solid breast lesions identified by ultrasonography if advanced MRI techniques are developed to improve its accuracy, particularly with better false negativity rates.
- CT Chest Abdomen Pelvis Doses in Scotland : Has the DRL had its day? [JOURNAL ARTICLE]
- Br J Radiol 2014 Jun 27.:20140157.
Objectives: This paper reports on a pilot study designed to collect dose data representative of current CT Chest Abdomen Pelvis (CAP) practice in Scotland, make any immediately obvious interventions and to identify if the current UK DRL of 940 mGycm is still appropriate. The aims are to identify if a Scotland wide PACS based dose audit of a number of CT examinations is likely to have value in terms of optimisation of patient doses, and to comment on the significance of the results in terms of future optimisation strategies. Methods: Dose audit of CT CAP examinations at 32 different scanner sites across Scotland using accepted data collection and analysis methods. Minimum sample size was 30. Results: Results indicate that CT CAP doses are lower than previously reported (median 800 mGycm, 75th percentile 840 mGycm) but follow a distribution not in keeping with the concept of DRLs as presently implemented. Conclusions: There is value in a PACS dose audit project to provide serial snapshots of patient doses as optimisation efforts take place and to revise current knowledge about CT doses. In our opinion, the results call into question whether DRLs or the concept of 'achievable dose' are suitable for devising optimisation strategies once a certain degree of optimisation has taken place. Advances in knowledge: The results reported here suggest that it may be time to take a different approach to optimisation, concentrating on more refined tools than the DRL, which may have become more of a compliance tool than aid to optimisation.