Design and characterization of a prototype tertiary device for proton beam stereotactic radiosurgery.

Though potentially beneficial, proton beam stereotactic radiosurgery has not been adopted widely secondary to the technical challenge of safely delivering multiple focused beams of proton radiation. In this study, we describe the design and characterization of a proton beam stereotactic radiosurgery system that can be adopted by existing passive scattering systems. This system utilizes a helmet-like device in which patient-specific brass apertures required for final beam collimation are positioned on a scaffold that is separate from the treatment gantry. The proton snout is then fitted with a generic aperture to focus the primary proton beam onto the patient specific apertures that are in the helmet-like device. The patient-specific apertures can all be placed at the start of the treatment, thus treatment with multiple beams can be accomplished without the delay of switching the apertures. In this report we describe a prototype design of this collimation system and dosimetric testing to verify efficacy. Subsequently, we describe a custom 3D printing of a prototype device and report on overall localization accuracy using Winston-Lutz tests. Our results show that it is possible to develop an add-on device for proton beam radiosurgery that is safe and efficient and capable of wide adoption on existing proton delivery systems.

Proton vs Hyperarc™ radiosurgery: A planning comparison.

For many patients, stereotactic radiosurgery (SRS) offers a minimally invasive, curative option when surgical techniques are not possible. To date, the literature supporting the efficacy and safety of SRS treatment techniques uses photon beams. However, with the number of proton therapy facilities exponentially growing and the favorable physical properties of proton beam radiation therapy, there is an opportunity to develop proton therapy techniques for SRS. The goal of this paper is to determine the ability of clinical proton treatment planning systems to model small field dosimetry accurately and to compare various planning metrics used to evaluate photon SRS to determine the optimum beam configurations and settings for proton SRS (PSRS) treatment plans. Once established, these plan settings were used to perform a planning comparison on a variety of different SRS cases and compare SRS metrics between the PSRS plans and HyperArc™ (VMAT) SRS plans.

Laparoscopic management of common bile duct stones.

BACKGROUND: While laparoscopic cholecystectomy is widely accepted for therapy of cholecystolithiasis, controversy still exists concerning the management of common bile duct stones. Besides preoperative endoscopic papillotomy followed by laparoscopic cholecystectomy and open common bile duct surgery, management of common bile duct stones can be conducted by laparoscopy, if respective experience is available. METHOD: During laparoscopic cholecystectomy a cholangiography via the cystic duct is routinely performed. If bile duct stones are detected they are retrieved via the cystic duct or via incision of the common bile duct by insertion of a Fogarty catheter or Dormia basket. Exclusion criteria against simultaneous laparoscopic management include suspicion of malignancy, severe pancreatitis, or cholangitis. RESULTS: From November 1991 to March 2002, 200 patients primarily underwent laparoscopic therapy of bile duct stones. Retrieval was performed via cystic duct and common bile duct incision in 115 and 85 cases, respectively. Complete removal was achieved in 91%; complication rate and mortality was 7% and 0.5%, respectively. During the same period primary endoscopic papillotomy was necessary in 40 patients because of the above contraindications. CONCLUSIONS: When correct indications and surgical expertise are observed, simultaneous laparoscopic management of common bile duct stones represents a safe and minimally invasive alternative to a two-procedure approach.

Drug-induced lupus-like syndrome associated with severe autoimmune hepatitis.

Atorvastatin and other members of the statin family are widely used for the treatment of hypercholesterolaemia in order to reduce the risk of atherosclerosis and cardiovascular disease. Atorvastatin-induced adverse events are mostly mild and only a few cases of lupus-like syndrome or severe acute hepatitis have been documented. In this case report we describe a patient who developed an atorvastatin-induced severe autoimmune hepatitis. In addition, this patient presented with a concomitant systemic lupus-like syndrome which has been already described for statins but not in association with severe liver disease. Although the drug was immediately withdrawn the disease persisted and even deteriorated to a fulminant disease with evidence of acute hepatic failure. The patient failed to respond to conventional immunosuppression with corticosteroids and azathioprine. Only the introduction of intense immunosuppressive therapy, as used in solid organ transplantation, led to a complete and sustained recovery of the patient. Interestingly, the patient was HLA DR3- and HLA DR4-positive, which are well-known genetic factors associated with autoimmune diseases. This case is the first report of a drug-induced lupus-likesyndrome concomitant with a severe autoimmune hepatitis in a genetically predisposed patient.

Primary gastric B-cell lymphoma: results of a prospective multicenter study. The German-Austrian Gastrointestinal Lymphoma Study Group.

BACKGROUND & AIMS: Appropriate management of primary gastric lymphoma is controversial. This prospective, multicenter study aimed to evaluate the accuracy of endoscopic biopsy diagnosis and clinical staging procedures and assess a treatment strategy based on Helicobacter pylori status and tumor stage and grade. METHODS: Of 266 patients with primary gastric B-cell lymphoma, 236 with stages EI (n = 151) or EII (n = 85) were included in an intention-to-treat analysis. Patients with H. pylori-positive stage EI low-grade lymphoma underwent eradication therapy. Nonresponders and patients with stage EII low-grade lymphoma underwent gastric surgery. Depending on the residual tumor status and predefined risk factors, patients received either radiotherapy or no further treatment. Patients with high-grade lymphoma underwent surgery and chemotherapy at stages EI/EII, complemented by radiation in case of incomplete resection. RESULTS: Endoscopic-bioptic typing and grading and clinical staging were accurate to 73% and 70%, respectively, based on the histopathology of resected specimens. The overall 2-year survival rates for low-grade lymphoma did not differ in the risk-adjusted treatment groups, ranging from 89% to 96%. In high-grade lymphoma, patients with complete resection or microscopic tumor residuals had significantly better survival rates (88% for EI and 83% for EII) than those with macroscopic tumor residues (53%; P < 0.001). CONCLUSIONS: There is a considerable need for improvement in clinical diagnostic and staging procedures, especially with a view toward nonsurgical treatment. With the exception of eradication therapy in H. pylori-positive low-grade lymphoma of stage EI and the subgroup of locally advanced high-grade lymphoma, resection remains the treatment of choice. However, because there is an increasing trend toward stomach-conserving therapy, a randomized trial comparing cure of disease and quality of life with surgical and conservative treatment is needed.

Thoracoscopic resection of a pericardial cyst.

The development of new instruments that can be applied endoscopically opens up new possibilities for minimally invasive thoracic surgery. The surgical technique is exemplified by a thoracoscopic resection of a pericardial cyst. The benefits for the patient are impressive: minimization of surgical trauma and postoperative pain, a short convalescence, and an optimal cosmetic outcome.

Decrease of human serum fucosyltransferase as an indicator of successful tumor therapy.

Surgical removal of colon carcinomas leads to a decrease in the rate of incorporation of [14C]fucose into its endogenous acceptor in human serum; normal incorporation rates are attained within 14 days. A similar time course has been determined for alpha2- and alpha3-fucosyltransferase when either desialo- or desialodegalactofetuin are employed as exogenous acceptors. A correlation has also been seen between transferase activity and the therapeutic response of patients with breast cancer. These results indicate that the determination of fucosyltransferase activity can facilitate the diagnosis of neoplasia, and the success of surgery, chemotherapy, or radiation.

[Intracellular localisation of urea-cycle enzymes in liver (author's transl)]. / Intrazelluläre Lokalisation von Enzymen des Krebs-Henseleit-Cyclus in der Leber

Enzymes of the Krebs-Henseleit urea-cycle were localized by means of differential centrifugation and fractional tissue extraction in rat liver and in human liver. Argininosuccinatlyase (ASAL) and Argininosuccinatsynthetase (ASAS) represent enzymes of the soluble cytoplasmic fraction. Ornithine-ketoacid-transaminase(OKT), carbamyl-phosphate-synthetase (CPS) and ornithine-carbamyl-transferase (OCT) are localized in the mitochondrial and nuclei fractions of the liver cell. Most of the arginase activity is bound to subcellular structures (probably to nuclei). A small portion of arginase-activity was found in the soluble cytoplasmatic fraction. The enzymes of the Krebs-Henseleit urea-cycle are equally distributed in rat liver and in human liver. Differences in the subcellular localisation of (mitochondrial) enzymes in human liver could be attributed to mitochondrial breakage during tissue preparation and do not represent in-vivo conditions.