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G Morton

Publications and source records attributed to G Morton.

32 records · Page 2Linked to original sources
PubMed1998

Target position variability throughout prostate radiotherapy.

PURPOSE: To quantify the variability in prostate and seminal vesicle position during a course of external beam radiotherapy, and to measure the proportion of target variability due to setup error. METHODS AND MATERIALS: Forty-four weekly planning computerized tomography (CT) studies were obtained on six patients undergoing radiotherapy for prostate cancer. All patients were scanned in the radiotherapy treatment position, supine with an empty bladder, with no immobilization device. All organs were outlined on 3-mm-thick axial CT images. Anterior and lateral beam's eye view digitally reconstructed radiographs and multiplanar reformatted images were generated. The position of the prostate and seminal vesicles relative to the isocenter location as set that day was recorded for each CT study. Target position relative to a bony landmark was measured to determine the relative contribution of setup error to the target position variability. RESULTS: The seminal vesicle and prostate position variability was most significant in the anterior-posterior (AP) direction, followed by cranial-caudal (CC) and mediolateral (ML) directions. Setup error contributed significantly to the total target position variability. Rectal filling was associated with a trend to anterior movement of the prostate, whereas bladder filling was not associated with any trends. Although most deviations from the target position determined at the initial planning CT scan were within 10 mm, deviations as large as 15 mm and 19 mm were seen in the prostate and seminal vesicles respectively. Target position variations were evenly distributed around the initial target position for some patient studies, but unpredictable patterns were also seen. From a simulation based on the observed variability in target position, the AP, CC, and ML planning target volume (PTV) borders around the clinical target volume (CTV) required for target coverage with 95% certainty are 12.4 mm, 10.3 mm, and 5.6 mm respectively for the prostate and 13.8 mm, 8.6 mm, and 3.9 mm respectively for the seminal vesicles. CONCLUSION: Target position variability is significant during prostate radiotherapy, requiring large PTV borders around the CTV. This target position variability may be potentially reduced by improving the setup accuracy.

Humans↗
PubMed1984

Isolation and identification of piperacillin amide as an impurity in piperacillin.

Piperacillin amide (IV) was successfully identified as the predominant impurity in commercial lots of piperacillin monohydrate (III). The impurity was isolated via a preparative liquid chromatographic scheme utilizing Florisil as the adsorbent and a mobile phase of water-acetonitrile (4:96, v/v). The isolated component had nearly the same reverse-phase HPLC properties as piperacillin and was chemically and thermally unstable. This labile impurity was spectroscopically identified by field desorption (FD), fast atom bombardment (FAB) with collision activation decomposition (CAD), and desorption chemical ionization (DCI) mass spectrometries , and NMR and IR spectrometries . Identity was confirmed on comparison of the chromatographic and spectrometric data of the impurity with an independently synthesized sample of piperacillin amide.

Chemical Phenomena↗
PubMed1982

Measurement of strabismus in shortened exam lanes versus the 20-foot lane.

The angle of strabismus was compared in 62 patients when measured at 10 feet and in a 20-foot mirrored system, to measurements at 20 feet. Several divergence excess type exodeviations were measured as being significantly less, relative to the 20-foot measurements. High accommodative convergence/accommodation ratio type esotropes were often measured as being significantly higher in the 10-foot room, relative to the 20-foot measurements. Having a shortened or mirrored lane for strabismus measurement could significantly alter the mode of treatment or amount of surgery in strabismus patients and possibly yield a less than optimal result in strabismus management.

Esotropia↗
PubMed1981

Adherence of Neisseria meningitidis to human epithelial cells.

Carrier strains of Neisseria meningitidis are recovered almost solely from the posterior pharynx and they are often nongroupable or rough. Invasive strains can be serogrouped (encapsulated). We studied adherence of both carrier- and patient-derived serogroupable and nongroupable meningococci to buccal epithelial and posterior pharyngeal cells. Fresh meningococcal isolates attached significantly better to pharyngeal than to buccal cells (P = 0.01). Strains that could be serogrouped adhered less than nongroupable strains (P less than 0.05). Meningococci passed in vitro became hemagglutinin negative and nonpiliated. Hemagglutinin-negative meningococci always adhered less to both epithelial cell types than the hemagglutinin-positive variants of the same strain. These results indicate that meningococcal pili probably mediate attachment to oropharyngeal cells, but encapsulation may reduce adherence. Localization of meningococci in the posterior pharynx is in part explained by the receptivity of the epithelial cells in this area for meningococci.

Cheek↗
PubMed1981

Management of the incontinent patient. Practical guidelines for home care.

Probably no condition produces such an emotive reaction on the part of both patient and care-giver as that of incontinence. It has profound implications psychosocially to both parties, and is often erroneously viewed as an inevitable corollary of the ageing process, being one of the most damning hallmarks of decline, and a potent cause of rejection. This article suggests practical ways in which incontinence can be coped with at home.

Attitude↗
PubMed1977

An improved method of fitting resultant prism in treatment of two-axis strabismus.

A new chart determines resultant prism power and angle when correction of combined horizontal and vertical deviation with a single prism, set at an angle intermediate between horizontal and vertical, is desired. The chart is based on a derivation so weighted as never to permit a vertical error greater than one tenth as large as the associated horizontal error, with use of commercially available sizes of plastic Fresnel-type prisms. This weighting takes into account differences in horizontal and vertical fusional reserves. A compass rose facilitates proper alignment of the prisms.

Humans↗
PubMed1975

Frustration.

Explore the source record for details and available documents.

Nursing↗
PubMedDate not supplied

Role of radiotherapy in the treatment of cancer of the ovary.

The initial management of carcinoma of the ovary is surgical. The need for further treatment is determined by a consideration of tumor stage, grade, and the presence of residual disease. Approximately one-third of patients are suitably managed by primary post-operative radiotherapy directed to the entire abdomen and pelvis with curative intent. Patients are mainly derived from stages I and II. Stage III patients are also included if the tumor is of low grade and there is no pelvic residuum. The dose which can be safely delivered to the upper abdomen is limited by normal tissue tolerance. Curative radiation is inappropriate for patients with upper abdominal disease and/or more than small volume residuum in the pelvis. These patients are best managed with chemotherapy. Suitably selected patients have a ten-year relapse-free survival of 68% following radiotherapy. Acute gastrointestinal symptoms are common during the treatment, but are usually amenable to symptomatic management. Long term morbidity is infrequent, and with modern techniques the incidence of treatment-related small bowel obstruction is around 5%. Radiotherapy to the abdomen and pelvis has also a potential role as consolidative treatment in patients with advanced disease, following a favourable response to chemotherapy.

Combined Modality Therapy↗