Linac4 H⁻ ion sources.

CERN's 160 MeV H(-) linear accelerator (Linac4) is a key constituent of the injector chain upgrade of the Large Hadron Collider that is being installed and commissioned. A cesiated surface ion source prototype is being tested and has delivered a beam intensity of 45 mA within an emittance of 0.3 π ⋅ mm ⋅ mrad. The optimum ratio of the co-extracted electron- to ion-current is below 1 and the best production efficiency, defined as the ratio of the beam current to the 2 MHz RF-power transmitted to the plasma, reached 1.1 mA/kW. The H(-) source prototype and the first tests of the new ion source optics, electron-dump, and front end developed to minimize the beam emittance are presented. A temperature regulated magnetron H(-) source developed by the Brookhaven National Laboratory was built at CERN. The first tests of the magnetron operated at 0.8 Hz repetition rate are described.

Status and operation of the Linac4 ion source prototypes.

CERN's Linac4 45 kV H(-) ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma, and pulsed high voltages are described. The first experimental results of two prototypes relying on 2 MHz RF-plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H(-) beam of 16-22 mA which has successfully been used for the commissioning of the Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ) accelerator, and chopper of Linac4.

Hypoxic antiblastic stop-flow perfusion: clinical outcome and pharmacokinetic findings.

Stop-flow perfusion (SFP) is a recently implemented locoregional treatment based on the vascular isolation of the tumor bearing body district through a radiointerventistic technique. SFP is currently under investigation as a palliative therapeutic option for patients with locally advanced tumors. This paper reports on the results of our prospective study of limb and pelvic SFP. Thirty-seven patients were treated with SFP. No postoperative deaths occurred. Locoregional and systemic toxicity were observed after 22 and 31 treatments, respectively; complete and partial response after 3 (6%) and 24 (51%) SFPs, respectively. The pharmacokinetic study showed that pelvic SFP was associated with a leakage rate higher than femoral SFP (38% vs 28%). In conclusion, SFP is a feasible procedure. Toxicity and tumor response rates strictly depend upon drug leakage control.

Assessment of vascularized fibular graft one year after reconstruction of the wrist after excision of a giant-cell tumour.

We report a patient in whom the distal radius was resected for a giant cell tumour and the bone defect was replaced using a vascularized proximal fibular graft. The graft was viable and hypertrophied and normal callus formed on the distal radius. Due to chronic instability of the wrist the patient underwent revision arthrodesis 1 year after resection. Microscopic studies of the epishyseal region of the fibula showed wide necrosis of the graft with active creeping substitution. Despite the good technical result of the vascularized fibular graft, the vascularization was incomplete in the proximal epiphysis. We discuss possible reasons for this.

An atypical presentation of Paget's disease in an immunocompromised individual. A case report.

Paget's disease of bone is a localized disorder of bony resorption. The mechanism underlying the development of the disease remains controversial. There is substantial evidence suggesting a genetic basis for Paget's disease in some patients. A viral etiology of Paget's disease has been advocated. A further hypothesis implicating an immunological mechanism for this disease is based on growing evidence reviewed in the text. The presented case showed clinical and X-ray features typical of a very aggressive form of Paget's disease. We hypothesize that the extreme local aggressiveness of this case was secondary to the patient's concomitant immunosuppression due to an extended therapy following renal transplant.