Expanding the PET radioisotope universe utilizing solid targets on small medical cyclotrons.

Molecular imaging with medical radioisotopes enables the minimally-invasive monitoring of aberrant biochemical, cellular and tissue-level processes in living subjects. The approach requires the administration of radiotracers composed of radioisotopes attached to bioactive molecules, the pairing of which considers several aspects of the radioisotope in addition to the biological behavior of the targeting molecule to which it is attached. With the advent of modern cellular and biochemical techniques, there has been a virtual explosion in potential disease recognition antigens as well as targeting moieties, which has subsequently opened new applications for a host of emerging radioisotopes with well-matched properties. Additionally, the global radioisotope production landscape has changed rapidly, with reactor-based production and its long-defined, large-scale centralized manufacturing and distribution paradigm shifting to include the manufacture and distribution of many radioisotopes via a worldwide fleet of cyclotrons now in operation. Cyclotron-based radioisotope production has become more prevalent given the commercial availability of instruments, coupled with the introduction of new target hardware, process automation and target manufacturing methods. These advances enable sustained, higher-power irradiation of solid targets that allow hospital-based radiopharmacies to produce a suite of radioisotopes that drive research, clinical trials, and ultimately clinical care. Over the years, several different radioisotopes have been investigated and/or selected for radiolabeling due to favorable decay characteristics (i.e. a suitable half-life, high probability of positron decay, etc.), well-elucidated chemistry, and a feasible production framework. However, longer-lived radioisotopes have surged in popularity given recent regulatory approvals and incorporation of radiopharmaceuticals into patient management within the medical community. This review focuses on the applications, nuclear properties, and production and purification methods for some of the most frequently used/emerging positron-emitting, solid-target-produced radioisotopes that can be manufactured using small-to-medium size cyclotrons (≤24 MeV).

Surgical and Radiotherapeutic Management of Malignant Extradural Spinal Cord Compression.

Malignant spinal cord compression is one of the most dreaded complications of advanced malignancy, with patients presenting with progressive paralysis, paresthesia and/or autonomic dysfunction. The choice of management should be guided by the expected prognosis and outcome, not just from a neurological function point-of-view but also from the metastatic cancer itself. The main indications for surgery are: impending cord compression, spinal instability from tumour progression, bony retropulsion, for tissue diagnosis and for pain resistant to conventional therapies. Here, surgical principles, traditional and novel techniques and complications will be reviewed. For radiotherapy, multiple randomised studies have shown that for most patients a single fraction of external radiation has the same functional outcomes compared with multi-fractionation protocols. The experience of a specialised centralised interdisciplinary team will also be discussed.

Neurosurgical contribution within a complex NF1 supraregional service.

OBJECTIVES: The goal of this study was to review and present neurosurgical related activity within a multidisciplinary nationally commissioned specialty neurofibromatosis type I (NF1) center. PATIENTS & METHODS: We reviewed all NF1 Neurosurgical MDTs, NF1 Neurosurgical clinics and all neurosurgical procedures carried out in NF1 patients over an 8-year period. RESULTS: Since the inception of the service in 2009, 1505 cases were discussed at our NF-1 multidisciplinary meeting, 171 clinic appointments in complex NF1 patients with neurosurgical pathologies and 43(cranial and spinal) operations were performed. CONCLUSIONS: The formation of a supraregional multidisciplinary team allows for a better understanding of the disease, a comprehensive evaluation of neuroimaging findings and a steep learning curve in the management of NF1 surgical conditions. We provide holistic treatment for these patients via direct care, specialist advice and liaison with local units.

Pseudomeningocele presenting with cauda equina syndrome: is a 'ball-valve' theory the answer?

Pseudomeningocele is an uncommon complication of spinal surgery. The condition is most often asymptomatic and self-limiting. A proportion of patients may present with lower back pain, dural fistulas, radiculopathy or myelopathy. Cauda equina syndrome due to a pseudomeningocele has been reported due to herniation of the Cauda equina roots through the dural defect. We report a case of large pseudomeningocele causing an impending Cauda equina syndrome by acting as an extradural mass lesion.

The characteristics of neuronal injury in a static compression model of spinal cord injury in adult rats.

Studies of spinal cord injury using contusion (impact) injury paradigms have shown that neuronal death is an acute event that is largely over within 24 h. However, much less is known about cell death following compression injury, despite compression being a key component of natural spinal injuries. We have therefore used neuronal nuclei (NeuN) immunostaining to examine the spatiotemporal pattern of neuronal loss after static compression injury in adult rats. 3D reconstruction was used to reveal the full effect of the injury. Neuronal loss at the injury epicentre, assessed by NeuN immunostaining, amounted to 44% at 1 day but increased to 73% at 3 days and 81% at 1 month. Neuronal loss was also seen 5 mm rostral and caudal to the epicentre, but was not significant until 3 days. NeuN loss was greatest in the ventral horns and in the intermediate grey matter, with the lateral dorsal horns relatively spared. Cystic cavities formed after injury, but were not evident until 4 weeks and were small in size. In contrast to the slow profile of neuronal loss, the compression injury also evoked a transient expression of activating transcription factor-3 (ATF3) and activated c-Jun in neurons. ATF3 expression peaked at 3 days and declined at 7 days. Our spatiotemporal analysis of compression injury shows that neuronal loss is much more protracted than in contusion injury, and highlights the potential for neuroprotective strategies. This study is also the first indication of ATF3 involvement in spinal cord injury.

Vacuum assisted closure system in the management of enterocutaneous fistulae.

BACKGROUND: A very important yet often troublesome element in the conservative management of enterocutaneous fistulae is the protection of the surrounding skin from contact with the effluent. This report describes the successful use of a vacuum assisted closure (VAC) system in dealing with this problem. METHODS: The results of using the VAC system were studied in three patients with moderate or high volume output enterocutaneous fistulae where conventional treatment had failed to prevent skin excoriation. RESULTS: The VAC system was found to be highly effective in controlling fistula effluent and in promoting healing of excoriated skin in all three patients. Complete healing of the fistula was also achieved in two of the three patients. CONCLUSION: The VAC system can be an effective and economically viable method of containing fistula effluent and protecting the skin of patients with enterocutaneous fistulae. Contrary to conventional thought, the VAC system may also actually promote healing of the fistula.