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Biomedical subjects

C Westermann

Publications and source records attributed to C Westermann.

15 recordsLinked to original sources
PubMed2005

Two cases of fatal necrosis of the lesser pelvis in patients treated with combined radiotherapy and hyperthermia for cervical carcinoma.

This study reports two cases of fatal necrosis of the lesser pelvis in patients with advanced cervical carcinoma, who had received combined radiotherapy and hyperthermia. The necrosis reached far from the high dose area, in one of the cases even outside the radiation portals. Both patients initially had treatment-related morbidity which responded well to surgical treatment. After a disease-free interval, a rapidly progressive necrosis developed. Necrosis to this extent after combined modality treatment has, to the authors' knowledge, not been described.

Adult↗
PubMed2000

Dependence of the tray transmission factor on collimator setting and source-surface distance.

When blocks are placed on a tray in megavoltage x-ray beams, generally a single correction factor for the attenuation by the tray is applied for each photon beam quality. In this approach, the tray transmission factor is assumed to be independent of field size and source-surface distance (SSD). Analysis of a set of measurements performed in beams of 13 different linear accelerators demonstrates that there is, however, a slight variation of the tray transmission factor with field size and SSD. The tray factor changes about 1.5% for collimator settings varying between 4x4 cm and 40 x 40 cm for a 1 cm thick PMMA tray and approximately 3% for a 2 cm thick PMMA tray. The variation with field size is smaller if the source-surface distance is increased. The dependence on the collimator setting is not different, within the experimental uncertainty of about 0.5% (1 s.d.), for the nominal accelerating potentials and accelerator types applied in this study. It is shown that the variation of the tray transmission factor with field size and source-surface distance can easily be taken into account in the dose calculation by considering the volume of the irradiated tray material and the position of the tray in the beam. A relation is presented which can be used to calculate the numerical value of the tray transmission factor directly. These calculated values can be checked with only a few measurements using a cylindrical beam coaxial miniphantom.

Models, Theoretical↗
PubMed1999

Effect of electron contamination on scatter correction factors for photon beam dosimetry.

Physical quantities for use in megavoltage photon beam dose calculations which are defined at the depth of maximum absorbed dose are sensitive to electron contamination and are difficult to measure and to calculate. Recently, formalisms have therefore been presented to assess the dose using collimator and phantom scatter correction factors, Sc and Sp, defined at a reference depth of 10 cm. The data can be obtained from measurements at that depth in a miniphantom and in a full scatter phantom. Equations are presented that show the relation between these quantities and corresponding quantities obtained from measurements at the depth of the dose maximum. It is shown that conversion of Sc and Sp determined at a 10 cm depth to quantities defined at the dose maximum such as (normalized) peak scatter factor, (normalized) tissue-air ratio, and vice versa is not possible without quantitative knowledge of the electron contamination. The difference in Sc at dmax resulting from this electron contamination compared with Sc values obtained at a depth of 10 cm in a miniphantom has been determined as a multiplication factor, Scel, for a number of photon beams of different accelerator types. It is shown that Scel may vary up to 5%. Because in the new formalisms output factors are defined at a reference depth of 10 cm, they do not require Scel data. The use of Sc and Sp values, defined at a 10 cm depth, combined with relative depth-dose data or tissue-phantom ratios is therefore recommended. For a transition period the use of the equations provided in this article and Scel data might be required, for instance, if treatment planning systems apply Sc data normalized at d(max).

Electrons↗
PubMed1995

Increased phosphotyrosine in breast cancer tissue is associated with a worse prognosis.

We have previously demonstrated that phosphotyrosine can be identified in breast cancer cells using an immunohistochemical stain. We have subsequently used this technique to characterize 106 women with breast cancer (46 with Stage 1 and 60 with Stage 2) who have been followed for at least four years by one oncologist. We analyzed all primary breast cancer tissue using immunohistochemical staining and the amount of phosphotyrosine (PT) was scored on a 0 to 3 range. The PT score of the primary tumor was unrelated to either breast cancer stage or estrogen and progesterone receptor analysis, as high PT scores were noted in both disease stages and all receptor categories. We did find that patients with either no or trace (1+) amounts of PT survived longer than those patients with higher amounts of PT. The patients with low PT had significantly lower chance of relapse (Chi Square = 15.8, p < 0.001) and a lower mortality (Chi Square = 13.1, p = 0.001). We conclude that immunohistochemical methods to determine the PT score may identify patients at higher risk for disease relapse independent of tumor stage or hormonal status.

Breast Neoplasms↗
PubMed1989

The value of CT scanning in the management of patients with gynecologic malignancies.

The management of gynecologic malignancies is exceedingly complex, requiring thoughtful coordination of surgery, radiation therapy and chemotherapy. Despite the fact that the natural history and clinical course of these cancers are generally well understood, the scarring caused by surgery and/or radiation, and the marked limitations of pelvic examination make clinical staging and evaluation of limited value and known inaccuracy in following women with ovarian, cervical, uterine, vulvar and vaginal cancers. Understandably, the development of computerized axial tomography (CT), and its ability to visualize the abdomen and pelvis, lead to rapid acceptance of CT scans in defining extent of cancer and following patient response to various therapeutic interventions (Chen et al. 1980; Feigen et al. 1987; Photopoulos et al. 1977). Authors have compared the accuracy of CT findings with physical examination, surgical findings, lymphography, conventional radiography or ultrasound (Clarke-Pearson et al. 1986; Vercamb et al. 1987; Amendola 1981; Kerr-Wilson et al. 1984). However, little has been written on the effect of CT scanning on patient management. If we define and accept the accuracy of CT scanning in detecting pelvic and abdominal disease, can we show a benefit in patient management? Or, does CT scanning provide us with expensive information, or misinformation, which fails to translate into better patient care. Do complex imaging modalities compliment thorough examination and experienced clinical judgement, or only duplicate findings and provide extraneous information? To answer these questions, eighty-one months experience in using CT scanning in managing patients with gynecologic malignancies was reviewed.

Biopsy↗
PubMed1987

Ovarian metastases from stage IB adenocarcinoma of the cervix.

At the time carcinoma of the cervix is treated by radical surgery, it is believed that ovarian preservation is possible, and will prevent surgical menopause, with its risks of osteoporosis, vaginal dryness, and "hot flashes." However, the data originally used to justify ovarian preservation was based on clinical experience with squamous cell carcinoma of the cervix. Little if any data exist to justify this treatment rationale in patients with adenocarcinoma of the cervix. Two patients who presented with clinical Stage IB adenocarcinoma of the cervix, subsequently underwent radical surgical treatment. Pathologic review of the operative specimens revealed microscopic metastasis to the ovaries in both patients. It is suggested that ovarian preservation at the time of radical surgical treatment for adenocarcinoma of the cervix has not had its safety established, and that sacrificing the ovaries and providing hormonal replacement postoperatively may be a safer course.

Adenocarcinoma↗
PubMed1986

Routine appendectomy in extensive gynecologic operations.

Based upon past clinical experience, a policy was established in a teaching service to remove the appendix whenever encountered during extensive gynecologic operations. Retrospectively, all patients operated upon during the subsequent 54 month period were reviewed to determine the success of instituting the policy of mandatory elective appendectomy and to assess the pathologic findings. We found that 93 per cent of the time the policy was followed and appendectomy performed. Definite pathologic findings were found in 14.6 per cent of the specimens and equivocal pathologic findings in an additional 14 per cent. No procedure related morbidity occurred. The incidence of metastasis to the appendix from specific gynecologic malignant diseases is discussed herein.

Adolescent↗
PubMed1985

RO-TAGE biopsy. An improved method of endocervical evaluation.

The colposcopic management of patients with abnormal Papanicolaou smears relies on correlating the examination findings with the cytology and biopsy results. Failure to adequately sample the endocervical canal introduces a possible source of error and could allow an invasive lesion to be missed. In 300 patients subjected to both endocervical curettage and RO-TAGE biopsy (Proto Med Incorporated, Boulder, Colorado), significantly fewer inadequate samples were obtained with RO-TAGE biopsy (1%) or the use of both methods (0.3%) than with curettage alone (4.3%). Therefore, we conclude that RO-TAGE biopsy should be added to every colposcopic examination.

Biopsy↗
PubMed1977

Massive doses of methylprednisolone (30 mg/kg) in man: immediate haemodynamic effects in "low output state".

Methylprednisolone, 30 mg/kg body weight, was given as an intravenous bolus injection to a total of 31 cardiosurgical patients. Measurements of left ventricular parameters showed no significant increase in dp/dtmax and no significant decrease in left ventricular end-diastolic pressure. There were no important changes in blood pressure, heart rate, cardiac index, stroke index and total peripheral resistance. During 'steady state' extracorporeal circulation no relevant vasodilating effect could be found. In comparison to a control-group there were no important differences in haemodynamic parameters. In cardio-surgical patients, --mainly functional class III--we were unable to demonstrate any gross cardiovascular effects of large doses of methylprednisolone.

Adult↗