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Biomedical subjects

F M Khan

Publications and source records attributed to F M Khan.

At least 55 records · Page 3Linked to original sources
PubMed1985

Antacid regimen in reducing gastric fluid acidity--comparison of conventional oral antacids with cimetidine.

281 patients, divided into two groups, were given single 30 ml dose of five different conventional oral antacids (sodium citrate, 0.3 M Maalox, Gelusil, Alludrox and Mucaine), separately and in combination with Cimetidine to study their effect on decreasing the acidity of stomach contents. In 181 patients receiving varying types of conventional oral antacids, 2-10 percent of the patients had pH less than 3, regardless of the antacid received. In 100 patients of Cimetidine plus antacid group, none of the patients had pH less than 4.83, maximum being 8.2. With thick particulate oral antacids, no-mix between gastric juice and antacid was noticed in approximately 5-10 percent of cases. Cimetidine combined with oral antacid was the safest regimen to reduce the gastric fluid acidity.

Adolescent↗
PubMed1983

Monte Carlo evaluation of the Sievert integral for brachytherapy dosimetry.

The Sievert integral, widely used to compute dose distributions about filtered line sources, assumes that the emitted energy fluence is exponentially attenuated by the filter thickness traversed by the primary photons. To evaluate this approximation, a Monte Carlo simulation was performed realistically modelling the diffusion and energy degradation of primary photons due to coherent, incoherent and photoelectric interactions in the source filter. Estimates of the exposure rate at points near the source were obtained using analytical averaging. Comparison of the two models shows that for 226Ra and 192Ir sources, the Sievert algorithm consistently overestimates the exposure rate per unit activity. However, such errors may be significantly reduced if source intensity is expressed in terms of exposure rate. Computed exposure rate distributions based on exposure rate calibrations are also less sensitive to uncertainties in available spectroscopic data.

Brachytherapy↗
PubMed1983

Tangential fields. Improved reproducibility for breast-cancer treatment.

The authors describe an isocentric technique to set up tangential fields for breast-cancer therapy. The setup parameters (source-to-surface distance measured at the midline of the sternum, lateral shift of the treatment couch, and the gantry angle) are predetermined from a computed-tomographic image and a transverse contour which is obtained under treatment-like conditions. This procedure does not require breast immobilization and does not rely on skin marks on the breast.

Breast Neoplasms↗
PubMed1983

A six-month parallel group comparison of fenbufen and naproxen in the treatment of rheumatoid arthritis.

Thirty patients with definite or classical rheumatoid arthritis were enrolled in a six-month, prospective, double-blind study. Fifteen patients received 750 mg/day of naproxen and 15 patients received 900 mg/day of fenbufen. The fenbufen-treated group showed significant improvement in four parameters: pain at rest, pain on movement, duration of pain, and number of swollen joints. Naproxen produced significant improvement in three parameters: pain at rest, duration of morning stiffness, and number of swollen joints. There were no significant differences between treatments in any of the parameters at any assessment except for duration of morning stiffness at one observation point. Marked differences were noted in the number of patients with side effects and in the number of side effects reported. In the naproxen-treated group, 11 patients reported a total of 20 adverse reactions, while in the fenbufen-treated group, five patients reported a total of eight adverse reactions. Throughout the period of assessment, no consistent changes in laboratory values were observed. One patient in the naproxen-treated group showed an abnormal WBC at the third and fourth assessment, but this was not considered drug related. These results suggest that fenbufen is at least as effective as and better tolerated than naproxen in the treatment of patients with rheumatoid arthritis.

Anti-Inflammatory Agents↗
PubMed1982

Methods for routine calibration of brachytherapy sources.

Two types of routine geometry calibrators, the nuclear medicine dose calibrator and a Lucite jig holding a 30-ml external beam ion chamber with the source in a rigid geometry, were compared with open-air measurements for 137Cs, 192Ir, and 226Ra brachytherapy sources. The proximity of scattering surfaces in the second apparatus resulted in significant distortion of the buildup effect and deviation from the inverse square law (5% to 15%). For the dose calibrator, the response/Roentgen was found to be dependent not only on source energy, but on source capsule thickness as well. Approximately one half of the observed variation (27%) in calibration factors was accounted for by differences in filtration among sources. A mathematical logarithm that corrects for these geometric and filtration effects is presented. In addition, the activity assay procedure provided by the manufacturer of the dose calibrator is shown to be unsuitable for brachytherapy sources. Steps to overcome these problems are discussed.

Brachytherapy↗
PubMed1982

The relationship between milligram-hours and dose to point A in carcinoma of the cervix.

The relationships between the Fletcher and Manchester methods in dosimetry of cancer of the uterine cervix were explored in order to compare dose prescriptions between the systems, to optimize the best features of both systems, and to establish the necessity for computerized dosimetry. A total of 91 Fletcher-Suit radium applications was analyzed by a linear least-square regression analysis to compare Point A and Point B doses of the Manchester system will milligram-hours of the fletcher system. Although moderately high correlations were found between milligram-hours of radium and doses at Point A and Point B, it was concluded that direct comparisons, particularly between individual patients, are fraught with dose uncertainties of clinical significance. In addition, the correlation between milligram-hours of radium and Point A dose was markedly affected by the position of the colpostats and tandem, thus making it difficult to formulate a simple conversion factor between the two systems.

Brachytherapy↗
PubMed1979

Total-body superficial electron-beam therapy using a multiple-field pendulum-arc technique.

A technique using pendulum-arc rotation is presented for electron-beam treatment of generalized superficial malignancies. The technique consists of six arcing fields symmetrically dispersed around the body surface for circumferential coverage. The arc angle is selected to scan the height of the body fully. Beam uniformity within 10% over a height of 180 cm is achieved at a treatment distance of 385 cm. Randophantom dosimetry, using an 8 MeV electron beam degraded by 3/8 in. Plexiglas, indicates a surface dose uniformity within +/- 7% over most of the body surface. Underdosages occur at regions obstructed by adjacent body parts.

Abdomen↗
PubMed1978

Second neoplasms following megavoltage radiation in a pediatric population.

Previous reports of radiation-related neoplasia have relied primarily upon patients treated by orthovoltage to low doses for benign disease. This survey is believed to be the first to assess the incidence of second neoplasms following megavoltage therapy. The source was the records of all long-term pediatric survivors (88 patients) who were treated with megavoltage radiation (cobalt 60) at the University of Minnesota. There was an average follow-up period of 14 years during which 7 second neoplasms were discovered (8%). Five were not associated with prior radiation. Both radiation-related neoplasms were associated with low doses and one was without significant morbidity. Two of the seven neoplasms were malignant; one was not associated with radiation while the other was associated with prolonged chemotherapy and low dose radiation (1%). The only fatal second neoplasm was not associated with radiation but developed 5 years after prolonged chlorambucil treatment. This review reveals the tendency of childhood cancer victims to develop other neoplasms regardless of radiation. The finding of neoplasia induction only at low radiation doses supports the Gray hypothesis of decreased tumor induction at high doses through increased cell killing.

Adolescent↗