The low energy X-ray response of the LiF:Mg:Cu:P thermoluminescent dosemeter: a comparison with LiF:Mg:Ti

LiF:Mg:Cu:P thermoluminescent dosemeters (TLD) can be used for the same X-ray dosimetry applications as LiF:Mg:Ti, with each type having the disadvantage of a response dependent on energy, particularly at low energies. Measurements were made of the response per unit air kerma of LiF:Mg:Cu:P and LiF:Mg:Ti to nine quasi-monoenergetic X-ray beams with mean energies from 12 keV to 208 keV. Each measurement was normalized to the value produced by 6 MV X-rays. LiF:Mg:Cu:P was found to under-respond to a majority of these radiations whereas LiF:Mg:Ti over-responded to a majority. Their smallest relative measured response was produced by the lowest energy beam, and the maximum measured relative response of 1.15+/-0.07 and 1.21+/-0.07 for LiF:Mg:Cu:P and LiF:Mg:Ti, respectively, occurred at 33 keV. Energy response coefficients were derived from these measurements to estimate the error introduced by using either type of TLD to measure the dose from an X-ray spectrum different to that used for its absolute response calibration. It was calculated that if the response of either type of TLD was calibrated at 100 kVp, then an error of no more than +/-2% would be introduced into measurements of tube output at potentials of 50-130 kVp. LiF:Mg:Cu:P was found to introduce a larger error (up to 30%) into the measurement of body exit dose than LiF:Mg:Ti at tube potentials of 40-150 kVp, if its absolute response was calibrated using the corresponding body entrance beam. The method should allow this type of error to be estimated in other dosimetry applications for either type of TLD.     

Vascular Complications of Transplantation: Part 2: Pancreatic Transplants

Vascular complications after solid organ transplantation are not uncommon and may lead to graft dysfunction and ultimately graft loss. A thorough understanding of the surgical anatomy, etiologies, and types of vascular complications, their presentation and the options for management are important for managing these complex patients. This article reviews the basic surgical anatomy, the vascular complications, and endovascular management options of vascular complications in patients with pancreas transplants.     

Introduction: economy of running: a multidisciplinary perspective.

This symposium endeavors to address the issue of running economy from a multidisciplinary perspective. Topics addressed in this symposium include physiological aspects of running economy, changes in running economy with age during childhood and adolescence, biomechanical considerations for economical walking and running, psychological state and running economy, and running economy of elite performers. While the knowledge base in this area is expanding, future research should emphasize the formulation of testable hypotheses and the fostering of collaborative efforts aimed at identifying and manipulating variables associated with improved economy and discovering mechanisms underlying economical running styles.     

Percutaneous Biliary Interventions: Inside and Outside the Box: Gallbladder: Role of Interventional Radiology

Percutaneous cholecystostomy is an established procedure for the management of patients with acute cholecystitis and with significant medical comorbidities that would make laparoscopic cholecystectomy excessively risky. In this review, we will explore the role of percutaneous cholecystostomy in the management of acute cholecystitis as well as other applications in the management of biliary pathology. The indications, grading, technical considerations, and postprocedure management in the setting of acute cholecystitis are discussed. In addition, we will discuss the potential role of percutaneous cholecystostomy in the management of gallstones and biliary strictures, in establishing internal biliary drainage, and in a joint setting with other clinicians such as gastroenterologists in the management of complex biliary pathology.     

The lumbar facet joint: a review of current knowledge: Part II: diagnosis and management

This article is the second article in a two-part review on lumbar facet joint pathology. In this review, we discuss the current concepts and controversies regarding the proper diagnosis and management of patients presenting with presumed facet-mediated lower back pain. All efforts were made to include the most relevant literature from the fields of radiology, orthopaedics, physiatry, and pain management. Our focus in this article is on presenting the evidence supporting or refuting the most commonly employed injection-based therapies for facet-mediated lower back pain.     

MRI: imaging of stomach

The study is to determine the optimal MRI bowel preparation regime for visualization of the stomach anatomy. Eight healthy volunteers were asked to take water, 75% barium and blueberry juice. The image quality and tolerance of different stomach distension regime were evaluated. Blueberry juice gave the best distension, but the signal intensity was not very homogeneous. Taking into account the image quality, tolerability and adverse effects, it is concluded that water is the most desirable oral contrast for MR stomach imaging.     

Pediatrics: diagnosis of neuroblastoma

Neuroblastoma is the most common pediatric extracranial soft-tissue tumor, accounting for approximately 8% of childhood malignancies. Its prognosis is widely variable, ranging from spontaneous regression to fatal disease despite multimodality therapy. Multiple imaging and clinical tests are needed to accurately assess patient risk with risk groups based on disease stage, patient age, and biological tumor factors. Approximately 60% of patients with neuroblastoma have metastatic disease, most commonly involving bone marrow or cortical bone. Metaiodobenzylguanidine (mIBG) scintigraphy plays an important role in the assessment of neuroblastoma, allowing whole-body disease assessment. mIBG is used to define extent of disease at diagnosis, assess disease response during therapy, and detect residual and recurrent disease during follow-up. mIBG is highly sensitive and specific for neuroblastoma, concentrating in >90% of tumors. mIBG was initially labeled with (131)I, but (123)I-mIBG yields higher quality images at a lower patient radiation dose. (123)I-mIBG (AdreView; GE Healthcare, Arlington Heights, IL) was approved for clinical use in children by the Food and Drug Administration in 2008 and is now commercially available throughout the United States. The use of single-photon emission computed tomography and single-photon emission computed tomography/computed tomography in (123)I-mIBG imaging has improved certainty of lesion detection and localization. Fluorodeoxyglucose positron-emission tomography has recently been compared with mIBG and found to be most useful in neuroblastomas which fail to or weakly accumulate mIBG.