ABSTRACT
The Laitinen Stereoadapter 5000 from Sandstroem Trade and Technology was acceptance tested and commissioned for clinical use in a Fractionated Stereotactic Radiotherapy Program at our facility. The frame was implemented to function as a localization device for target delineation rather than as an immobilization device. The frame is of non-invasive nature utilizing ear plugs and a nasion bridge adapter as the connecting points with the patient's head. The reproducibility of the head frame position with respect to external skull reference points was tested. CT and MRI imaging studies were performed on a patient phantom with the stereoadapter in place. The target was delineated and target coordinates were calculated for two implanted targets. The phantom was positioned according to the target coordinates on a Siemens MXE Linear Accelerator by aid of the target positioning lasers. Radiographic port film images were taken with the circular fields typically used in stereotactic radiosurgery. A complete treatment isodose plan was performed and dosimetric accuracy was tested by positioning a small volume ionization chamber at the center of the target volume in the head phantom. The results of these tests were found to be clinically acceptable.
Subject(s)
Dose Fractionation, Radiation , Radiosurgery/instrumentation , Head/anatomy & histology , Head/diagnostic imaging , Head/surgery , Humans , Magnetic Resonance Imaging , Particle Accelerators , Phantoms, Imaging , Radiosurgery/methods , Tomography, X-Ray ComputedABSTRACT
An intra-oral lead shield was developed that consists of a lead base with an aluminum layer that is placed upstream of the lead base. Several such shields with various thicknesses of Al layers were manufactured and quantitatively evaluated in 6 MeV and 12 MeV electron radiation by Thermoluminescent dosimetry (TLD) measurements. The clinical relevance was established by using a 5 cm backscatter block down-stream of the lead shield to simulate anatomical structures of the head and a 0.5 cm superflab bolus upstream of the Al layers of the shield to simulate the patient's lip or cheek. The TLDs were placed between the Al layers of the shield and the superflab to determine the intra-oral skin dose. TLD exposure results revealed that 59.8% of the skin dose at 6 MeV and 45.1% of the skin dose at 12 MeV is due to backscattered electrons. Introduction of a 3.0 mm thick Al layer reduces the backscatter contribution to 13.5% of the back scatter dose at 6 MeV and 56.3% of the back scatter dose at 12 MeV electron radiation.
Subject(s)
Aluminum , Lead , Mouth/radiation effects , Radiation Protection/instrumentation , Radiotherapy/instrumentation , Scattering, Radiation , Cheek/radiation effects , Electrons , Equipment Design , Head/radiation effects , Humans , Lip/radiation effects , Radiation Dosage , Radiotherapy Dosage , Radiotherapy, High-Energy/instrumentation , Skin/radiation effects , Thermoluminescent DosimetryABSTRACT
Several methods for dose deposition of a given isodose distribution were developed by implementation of different techniques of accelerator use. Common to all of these methods is the time-dependent change of certain accelerator parameters during radiation treatment. The accelerators for which these methods can be used are equipped with independent collimator jaws, however, not with any kind of multileaf collimation. This method was designed to deposit a certain group of dose distributions that are restricted by a small number of constraints. The developed methods were implemented into a digitally controlled medical linear accelerator and the dosimetric results of such treatments were evaluated. Dose distributions with spatial dependencies in one and in two dimensions were deposited by movement of one X-ray jaw pair. Furthermore, a method for generation of a two-dimensional rotationally symmetric dose distribution was developed.
Subject(s)
Radiotherapy Dosage , Radiotherapy, Computer-Assisted , Algorithms , Equipment Design , Humans , Particle Accelerators , Radiotherapy/instrumentation , Radiotherapy, High-Energy , Signal Processing, Computer-Assisted , Time Factors , X-RaysABSTRACT
From October, 1993 to August, 1994, a post-marketing surveillance study enrolled 9,568 adults and children treated for respiratory tract infections with cefixime in a daily dose of 400 mg or 8 mg/kg body weight, respectively. Twice daily dosage was preferred with adults (60.4%) and children (54.4%). Bronchitis (45.5%) and otitis media (48.0%) were the most frequent indications given for cefixime use in adults and children, respectively. Bacterial analysis was done in 5.4% of adults and in 6.5% of children. With a median therapy of 6 days, cure or improvement was reported in 98.7% of adult patients and in 98.0% of children. Symptoms rapidly improved in a majority of patients. Adverse events occurred in 1.12% of adult patients and 1.92% of children. In 96.7% of all cases the dry syrup was very well or well accepted by children. In conclusion, high efficacy and low incidence of side effects make cefixime a drug of choice for treatment of respiratory tract infections.
Subject(s)
Cefotaxime/analogs & derivatives , Cephalosporins/therapeutic use , Respiratory Tract Infections/drug therapy , Adult , Cefixime , Cefotaxime/adverse effects , Cefotaxime/therapeutic use , Child, Preschool , Female , Humans , MaleABSTRACT
During conjugative transfer of sex pheromone plasmids of Enterococcus faecalis a so-called surface exclusion protein reduces the frequency with which these plasmids are transferred to cells already possessing the same plasmid. We report here the DNA sequence of a 3.8 kb fragment of the sex pheromone plasmid pAD1 containing the structural gene sea1 for surface exclusion protein and a small open reading frame (ORF) upstream of sea1. Surface exclusion protein Sea1 was found to be highly homologous to the surface exclusion protein Sec10 encoded by the sex pheromone plasmid pCF10. Hybridization studies with DNA probes derived from the structural gene sea1 demonstrated that, with the exception of pAM373, all known sex pheromone plasmids carry a homologous gene. These studies also indicated that the genetic organization is similar in these plasmids, with the structural gene for surface exclusion protein being located 5' to that for aggregation substance.
Subject(s)
Bacterial Proteins/genetics , Enterococcus faecalis/genetics , Plasmids , Sex Attractants/genetics , Amino Acid Sequence , Base Sequence , Blotting, Southern , Blotting, Western , Conjugation, Genetic , DNA Probes , DNA, Bacterial , Genes, Bacterial , Molecular Sequence Data , Nucleic Acid Hybridization , Open Reading Frames , Sequence Homology, Nucleic AcidABSTRACT
We evaluated the monoclonal antibody MAb, BW 250/183, which is easy to label with Tc-99m, with respect to its clinical application for the detection of inflammatory processes in bone and joint diseases. This monoclonal antibody is a murine immunoglobulin (IgG1 isotype), directed against NCA 95 (nonspecific cross-reacting antigen), which is also present on the surface of neutrophil granulocytes. We investigated patients with acute (n = 9) and chronic (n = 3) osteomyelitis, with coxitis (n = 3) and coxarthrosis (n = 2), with septic hip prosthesis (n = 8) and loosening hip prosthesis (n = 14), with low back pain (n = 4), with spondylitis (n = 5) and with postoperative spondylodiscitis (n = 9). With reference to the total number of patients examined in this study we found 29 true positive results, 22 true negative results, 4 false negative results and 2 false positive results. This gives a sensitivity of 88% and a specificity of 92%. The lesions were already visualized within 4 to 6 hours, but 24 hour pictures are desirable. SPECT pictures are mandatory in patients with diseases of the hip or of the spine because sensitivity is considerably improved thereby.