Study on the Tongue and Groove Effect of the Elekta Multileaf Collimator Using Monte Carlo Simulation and Film Dosimetry

BACKGROUND: Nowadays, multileaf collimation of the treatment fields from medical linear accelerators is a common option. Due to the design of the leaf sides, the tongue and groove effect occurs for certain multileaf collimator applications such as the abutment of fields where the beam edges are defined by the sides of the leaves. MATERIAL AND METHODS: In this study, the tongue and groove effect was measured for two pairs of irregular multileaf collimator fields that were matched along leaf sides in two steps. Measurements were made at 10 cm depth in a polystyrene phantom using Kodak EDR2 films for a photon beam energy of 6 MV on an Elekta Sli-plus accelerator. To verify the measurements, full Monte Carlo simulations were done. In the simulations, the design of the leaf sides was taken into account and one component module of BEAM code was modified to correctly simulate the Elekta multileaf collimator. RESULTS AND CONCLUSION: The results of measurements and simulations are in good agreement and within the tolerance of film dosimetry.     

American Society of Nuclear Cardiology review of the ACCF/ASNC appropriateness criteria for single-photon emission computed tomograph myocardial perfusion imaging (SPECT MPI)

Conclusion  The ACCF/ASNC AC for SPECT MPI provides recommendations for the appropriate use of SPECT MPI. After the publication of the AC document in 2005, the AC has been used by nuclear cardiology practices with many clinical studies evaluating the list of indications in routine clinical practice. From these data. ASNC recommends minor but important changes to the indication list, suggesting the addition of 6 new indications and the modification of the definitions for “chest pain syndrome” and “CHD high risk.”. An objective review of existing indications focused on only those indications that had significant variability among the reviewers (n=20). These indications were reviewed in the presence of existing and new evidence-based data, and ASNC recommends that the grades for 6 indications be re-evaluated. The AC for SPECT MPI will require periodic review as new evidence becomes available or as clinical practice evolves. ASNC recognizes the importance of these criteria to improve the quality of patient care, and it will continue to play a key role in assembling the information for this ongoing review. From the current summary of evidence, ASNC consensus opinions, and ASNC recommendations in this document, ASNC strongly recommends that the AC guidelines be reviewed Prepared by the American Society of Nuclear Cardiology Quality Assurance Subcommittee for Quality in Imaging Standards. Reviewed by members of the American Society of Nuclear Cardiology Quality Assurance Committee. Approved by the American Society of Nuclear Cardiology Board of Directors, September 6, 20.     

Comparison of Endovenous Treatment with an 810 nm Laser versus Conventional Stripping of the Great Saphenous Vein in Patients with Primary Varicose Veins

BACKGROUND: Patients with varicose veins seek medical assistance for many reasons, including esthetic ones. The development of suitable and more flexible instruments, along with less invasive techniques, enables the establishment of new therapeutic procedures. OBJECTIVE: To compare endovenous great saphenous vein photocoagulation with an 810 nm diode laser and the conventional stripping operation in the same patient. METHODS: Twenty patients selected for operative treatment of primary great saphenous vein insufficiency on duplex scanning were assigned to a bilateral random comparison. In all cases, both techniques were performed, one on each lower limb. Clinically, evaluation was assessed on the seventh, thirtieth, and sixtieth postoperative days. Patients underwent examination with duplex ultrasonography and air plethysmography during the follow-up. RESULTS: Patients who received endovenous photocoagulation presented with the same pain but fewer swellings and less bruising than the stripping side. Most patients indicated that the limb operated on by laser received more benefits than the other. There was only one recanalization and no adverse effects. The venous filling time showed better hemodynamics in both techniques. CONCLUSION: The endovenous great saphenous vein photocoagulation is safe and well tolerated and presents results comparable to those of conventional stripping.     

Development of an in vitro burn wound model

Healing of a deeper burn wound is a complex process that often leads to scar formation. Skin wound model systems are important for the development of treatments preventing scarring. The aim of this study is to develop a standardized in vitro burn wound model that resembles the in vivo situation. A burn wound (10 × 2 mm) was made in ex vivo skin and the skin samples were cultured at the air–liquid interface for 7, 14, and 21 days. Cells in the skin biopsies maintained their viability during the 21-day culture period. During culture, reepithelialization of the wound took place from the surrounding tissue and fibroblasts migrated into the wound area. Cells of the epithelial tongue and fibroblasts near the wound margin were proliferating. During culture, skin-derived antileukoproteinase and keratin 17 were expressed only in the epithelial tongue. Both collagen type IV and laminin were present underneath the newly formed epidermis, indicating that the basement membrane was restored. These results show that the burn wound model has many similarities to in vivo wound healing. This burn wound model may be useful to study different aspects of wound healing and testing pharmaceuticals and cosmetics on, e.g., migration and reepithelialization.     

Hämatologische Störungen bei Intensivpatienten

This final issue of the series "Emergency and intensive care therapy for hematooncological diseases" reviews cytopenias in intensive care patients who do not offer any oncological or haematological problems in their medical history. Anaemia is a very common problem in the intensive care setting. We highlight aetiological aspects of anaemia in critically ill patients and discuss therapeutical options like substitution of blood and application of erythropoietin, respectively. The second paragraph focuses on leukocytopenia and agranulocytosis, their causation and therapy and among other things the application of G-CSF (Granulocyte colony-stimulating factor). Last but not least, we deal with thrombocytopenia, especially heparin-induced thrombocytopenia.     

Prospective evaluation of the effect on initial brain metastases from small cell lung cancer of platinum-etoposide based induction chemotherapy followed by an alternating multidrug regimen

BACKGROUND:: During the 1980s reports describing the effect of systemic chemotherapyon brain metastases from chemosensitive tumours emerged, includinga few retrospective reports on small cell lung cancer (SCLC)patients. DESIGN:: Previously untreated SCLC patients with no other malignancy,but in some cases with mixed histological subtype, who had symptomaticbrain metastases verified by contrast enhanced CT-scan, weretreated with a multidrug combination chemotherapy regimen andno cranial irradiation. Radiotherapy was optional at cranialrelapse or progression at the discretion of the physician incharge. The intracranial effect was evaluated by 4-weekly CT-scanand neurological examination, according to a standardized scoringsystem. END POINTS:: Intracranial response, duration of response, neurological score,terminal CNS status, and survival. RESULTS:: 21 patients were included, corresponding to 8.6% of consecutiveSCLC patients at our institution. 8 patients died before follow-upleaving 13 evaluable for response. In the former group, allpatients had WHO performance status of 3–4 compared to6/13 in the latter group. Of the 13 evaluable patients, 1 hadearly progression in the CNS and 1 had no change. 11 had CT-scanverified response, with a median duration of 135 days. Mostpatients, including all complete responders, had improvementin their neurological score. 6 out of 11 responders died withoutactive CNS disease. The crude median survival was 111 days,whereas the median survival(early deaths excluded) was 197 days. CONCLUSION:: Systemic combination chemotherapy was effective for palliationof initial brain involvement in the majority of patients ina small consecutive series. The role of consolidating cranialirradiation in responders should be assessed by a randomizedtrial. small cell carcinoma, brain metastases, chemotherapy     

Tibial hypo-/aplasia with preaxial syn- and polydactyly

Summary Tibial hypo-/aplasia with preaxial syn- and polydactyly is a rare autosomal dominant condition. Fewer than 20 cases have so far been described. One is presented here.     

Neural classifier construction using regularization, pruning and test error estimation

In this paper we propose a method for construction of feed-forward neural classifiers based on regularization and adaptive architectures. Using a penalized maximum likelihood scheme, we derive a modified form of the entropic error measure and an algebraic estimate of the test error. In conjunction with optimal brain damage pruning, a test error estimate is used to select the network architecture. The scheme is evaluated on four classification problems.