A comparison study between single- and dual-energy CT density extraction methods for neurological proton monte carlo treatment planning.

Monte Carlo proton dose calculations requires mass densities calculated from the patient CT image. This work investigates the impact of different single-energy CT (SECT) and dual-energy CT (DECT) to density conversion methods in proton dose distributions for brain tumours.Material and methods: Head CT scans for four patients were acquired in SECT and DECT acquisition modes. Commercial software was used to reconstruct DirectDensity™ images in Relative Electron Densities (RED, [Formula: see text]) and to obtain DECT-based pseudo-monoenergetic images (PMI). PMI and SECT images were converted to RED using piecewise linear interpolations calibrated on a head-sized phantom, these fits were referred to as "PMI2RED" and "CT2RED". Two DECT-based calibration methods ("Hünemohr-15it" and "Saito-15it") were also investigated. [Formula: see text] images were converted to mass-densities ([Formula: see text]) to investigate [Formula: see text]differences and one representative patient case was used to make a proton treatment plan. Using CT2RED as reference method, dose distribution differences in the target and in five organs-at-risk (OARs) were quantified.Results: In the phantom study, Saito-15it and Hünemohr-15it produced the lowest [Formula: see text]root-mean-square error (0.7%) and DirectDensity™ the highest error (2.7%). The proton plan evaluated in the Saito-15it and Hünemohr-15it datasets showed the largest relative differences compared to initial CT2RED plan down to -6% of the prescribed dose. Compared to CT2RED, average range differences were calculated: -0.1 ± 0.3 mm for PMI2RED; -0.8 ± 0.4 mm for Hünemohr-15it, and -1.2 ± 0.4 mm for Saito-15it.Conclusion: Given the wide choice of available conversion methods, studies investigating the density accuracy for proton dose calculations are necessary. However, there is still a gap between performing accuracy studies in reference [Formula: see text]phantoms and applying these methods in human CT images. For this treatment case, the PMI2RED method was equivalent to the conventional CT2RED method in terms of dose distribution, CTV coverage and OAR sparing, whereas Hünemohr-15it and Saito-15it presented the largest differences.

Small bowel toxicity after high dose spot scanning-based proton beam therapy for paraspinal/retroperitoneal neoplasms.

PURPOSE: Mesenchymal tumours require high-dose radiation therapy (RT). Small bowel (SB) dose constraints have historically limited dose delivery to paraspinal and retroperitoneal targets. This retrospective study correlated SB dose-volume histograms with side-effects after proton radiation therapy (PT). PATIENTS AND METHODS: Between 1997 and 2008, 31 patients (mean age 52.1 years) underwent spot scanning-based PT for paraspinal/retroperitoneal chordomas (81%), sarcomas (16%) and meningiom (3%). Mean total prescribed dose was 72.3 Gy (relative biologic effectiveness, RBE) delivered in 1.8-2 Gy (RBE) fractions. Mean follow-up was 3.8 years. Based on the pretreatment planning CT, SB dose distributions were reanalysed. RESULTS: Planning target volume (PTV) was defined as gross tumour volume (GTV) plus 5-7 mm margins. Mean PTV was 560.22 cm(3). A mean of 93.2% of the PTV was covered by at least 90% of the prescribed dose. SB volumes (cm(3)) receiving doses of 5, 20, 30, 40, 50, 60, 70, 75 and 80 Gy (RBE) were calculated to give V5, V20, V30, V40, V50, V60, V70, V75 and V80 respectively. In 7/31 patients, PT was accomplished without any significant SB irradiation (V5=0). In 24/31 patients, mean maximum dose (Dmax) to SB was 64.1 Gy (RBE). Despite target doses of >70 Gy (RBE), SB received >50 and >60 Gy (RBE) in only 61 and 54% of patients, respectively. Mean SB volumes (cm(3)) covered by different dose levels (Gy, RBE) were: V20 (n=24): 45.1, V50 (n=19): 17.7, V60 (n=17): 7.6 and V70 (n=12): 2.4. No acute toxicity ≥ grade 2 or late SB sequelae were observed. CONCLUSION: Small noncircumferential volumes of SB tolerated doses in excess of 60 Gy (RBE) without any clinically-significant late adverse effects. This small retrospective study has limited statistical power but encourages further efforts with higher patient numbers to define and establish high-dose threshold models for SB toxicity in modern radiation oncology.

[Pediatric anesthesia for proton radiotherapy : medicine remote from the medical centre]. / Kinderanästhesie zur protonenbestrahlung : medizin fernab der klinik.

Anesthesia care for infants and young children for proton beam radiotherapy demands great technical and vocational skills from the anesthesia team and also a high degree of competence in soft skills. The anesthesia team should be experienced and regularly trained in pediatric anesthesia, especially as the children are often in a reduced general condition. The infrastructure should be established according to the current standards in anesthesiology. Monitoring of vital data, thorax excursions and inadvertent movements of the remotely positioned and sedated patient need to be under constant technical and optical surveillance. Propofol is an ideal hypnotic for the sedation of children under spontaneous breathing for proton beam radiation therapy. It is well tolerated even when given on a daily basis over several weeks. A close cooperation between the pediatric oncologist, radiation oncologist and anesthetist is important in order to manage additional medical problems in an optimal way. The special needs of oncology patients must be taken into consideration when planning anesthesia care.

Dumbbell-shaped thoracic chondroid chordoma mimicking a neurinoma.

A 31-year-old woman was admitted to the hospital with paraparesis and pyramidal signs. Magnetic resonance imaging disclosed a homogeneously enhanced mass occupying the spinal canal at the T1-T2 level and extending to the apical pleural space through the right intervertebral foramen. Surgical resection was achieved using a laminectomy and complete facetectomy. Histological examination indicated chondroid chordoma. The patient received postoperative proton radio-therapy. Chondroid chordoma is a subtype of chordomas with better prognosis, and it may appear as a dumbbell-shaped tumor as previously described in classical chordomas.

Proton therapy in paediatric oncology: an Irish perspective.

BACKGROUND: Proton therapy (PT) is a radiotherapy treatment modality that uses protons, rather than conventional photons. PT is often used in paediatric oncology due to its reported capability to reduce acute and late adverse treatment effects. As PT is unavailable in Ireland, patients are referred abroad for treatment. AIMS: To: (1) produce a descriptive study of Irish children referred abroad for PT, and (2) discuss the case for PT in general. METHODS: A retrospective review of all children referred for PT before October 2015 was performed. Information was gathered regarding demographics, diagnosis, referral timeline, adverse effects attributable to PT, current status and cost. A review of the relevant literature was performed. RESULTS: Seventeen children treated in Ireland have been referred abroad for PT. The largest number was in the 0-4 year old group. At initial diagnosis the median age was 4.8 years. The average cost per child was €37,312. Two patients suffered disease relapse. Four have encountered PT-related adverse effects. CONCLUSION: Despite the fact that >100,000 patients worldwide have been treated with PT, the level of published evidence to support superiority over conventional treatment remains low. It is debated that randomised control trials in this area would be inconsistent with the principle of clinical equipoise. In contrast, there is a call for level 1 evidence to justify drastic changes in patient care, particularly in light of recent reports of unexpected toxicities. In time, careful evaluation, follow-up and clinical trials will likely support the preferential use of PT in children.

Efficacy and safety of femoral vascular access for peripheral blood stem cell (PBSC) collection.

Central venous catheters are frequently used in leukapheresis to provide high flow rates. The most common locations are the subclavian or jugular vein, but insertion-related complications and inadequate flow are frequent problems. Experience using femoral venous access is limited, because this has been discouraged due to the high incidence of infectious or thromboembolic complications. We evaluated the safety and efficacy of 108 short-term femoral venous dialysis catheters used for the collection of peripheral blood stem cells (PBSCs). All catheters were placed by a member of the dialysis unit, and they remained in situ for the days needed to reach the target number of CD34+cells. No prophylactic antibiotic or antithrombotic therapy was used. A total of 232 apheresis sessions was performed. The longest duration a catheter remained in situ was 5 days. Most of the patients finished the collection in one or two apheresis sessions. There were no thrombotic or infectious complications, and insertion-related complications or mechanical problems were minimal. Apheresis results were similar to those reported using subclavian or jugular venous access. The short-term use of femoral venous dialysis catheters appears safe and effective for PBSC collection, simplifying the procedure, improving patient comfort, and reducing cost.

[Program of hypertransfusion and chelation with desferrioxamine in 10 patients with thalassemia major]. / Programa de hipertransfusión y quelación con desferrioxamina en diez pacientes afectos de talasemia maior.

PURPOSE: Thalassaemia maior is an inherited severe anaemia due to abnormal haemoglobin synthesis. Hypertransfusion therapy is based on the reduction of ineffective erythropoiesis and improvement of the anaemia. To prevent iron overload, continuous chelation therapy was performed with desferrioxamine (DFO). The efficacy of such management in 10 thalassaemia maior patients followed-up for 11 years has been evaluated. PATIENTS AND METHODS: Packed red-cell transfusions were administered to maintain haemoglobin rates over 100 g/L; 40 mg/Kg DFO was given five days a week subcutaneously. The mean age at the start of such treatment was 9.3 years. Clinical problems due to iron overload were evaluated, such as heart function, growth and development, endocrinopathies, along with DFO toxicity and complications of transfusion (positive indirect antiglobulin test (IAT), hepatitis, HIV infection). RESULTS: Two patients died of heart haemosiderosis. The mean ferritin values at the end of the study were around 3.031 mg/mL. Heart dysfunction was seen in 2 cases; 2 patients had retarded growth, decreased IGF-1 being found in both; 3 cases had hypogonadotropic hypogonadism, and 2 had clinical hypoparathyroidism. Bilateral opacification of the eye lens appeared in one patients as a consequence of prolonged DFO therapy. Positive IAT was found in 3 cases, and one patient developed positive hepatitis C serology. CONCLUSIONS: Control of iron deposits by iron chelators can prevent the damages of iron overload. Adequate accomplishment of programmes may be difficult, especially in children.

Motility-related protein-1 (MRP-1/CD9) expression can predict disease-free survival in patients with squamous cell carcinoma of the head and neck.

CD9 is a transmembrane protein that has been implicated in cell adhesion, motility and proliferation, and numerous studies have demonstrated the prognostic value of its expression in different solid tumours. The purpose of this study is to determine the predictive value of CD9 in squamous cell carcinoma (SCC) of the head and neck. A total of 153 cases were examined for CD9 expression using immunohistochemistry applied on formalin-fixed, paraffin-embedded tissue. Cases were stratified in two categories depending on CD9 expression, as positive (>/=50% positive cells) or reduced (<50%). In all, 108 cases were positive for CD9 (85 cases with membranous, and 23 with both membranous and cytoplasmic staining) and 45 reduced expression. Reduced CD9 expression was significantly associated with high grade (P=0.0007) and lower disease-free survival (DFS) (P=0.017). The latter retained its significance in the multivariate analysis. When the 23 cases with both membranous and cytoplasmic patterns were studied as a separate subgroup, there were significant associations between CD9 expression and tumour grade (P=0.025) (95% CI 11-68), tumour stage (P=0.08) (95% CI 3.5-86) and the occurrence of any failure (P=0.083) (95% CI -1.7-57). Immunohistochemical CD9 expression proved to be an independent prognostic factor in SCC of the head and neck, and it may detect patients at a high risk of recurrence. In addition, the cytoplasmic pattern seems to have an even more significant value. However, this finding is limited to the small number of cases with this pattern.

A mobile phone integrated health care delivery system of medical images.

With the growing computing capability of mobile phones, a handy mobile controller is developed for accessing the picture archiving and communication system (PACS) to enhance image management for clinicians with nearly no restriction in time and location using various wireless communication modes. The PACS is an integrated system for the distribution and archival of medical images that are acquired by different imaging modalities such as CT (computed tomography) scanners, CR (computed radiography) units, DR (digital radiography) units, US (ultrasonography) scanners, and MR (magnetic resonance) scanners. The mobile controller allows image management of the PACS including display, worklisting, query and retrieval of medical images in DICOM format. In this mobile system, a server program is developed in a PACS Web server which serves as an interface for client programs in the mobile phone and the enterprise PACS for image distribution in hospitals. The application processing is performed on the server side to reduce computational loading in the mobile device. The communication method of mobile phones can be adapted to multiple wireless environments in Hong Kong. This allows greater feasibility to accommodate the rapidly changing communication technology. No complicated computer hardware or software is necessary. Using a mobile phone embedded with the mobile controller client program, this system would serve as a tool for heath care and medical professionals to improve the efficiency of the health care services by speedy delivery of image information. This is particularly important in case of urgent consultation, and it allows health care workers better use of the time for patient care.

Un caso de rotura subcapsular del bazo en el parto / A case of subcapsular splenic rupture during labour

Se presenta un caso clínico de laceración subcapsular del bazo en el puerperio inmediato. Esta entidad es de gran dificultad diagnóstica tras el parto, dada su gran rareza clínica. Un punto muy importante es su sospecha y una rápida actuación al respecto para evitar una alta tasa de morbimortalidad

We report a case of subcapsular splenic rupture in the immediate postpartum period. Because of its rarity, this entity is difficult to diagnose. Key points are a high index of suspicion and rapid active management to avoid a high rate of morbidity and mortality