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Biomedical subjects

D Doughty

Publications and source records attributed to D Doughty.

At least 55 records · Page 3Linked to original sources
PubMed1997

Stereotactic multiple are radiotherapy. IV--Haemangioblastoma.

Our initial experience in the treatment of haemangioblastoma using conventional external beam radiotherapy and stereotactic radiotherapy (radiosurgery), by the linear accelerator method, is reported. Six haemangioblastomas in five patients were treated with a mean follow-up of 40 months (range 14-60). Five haemangioblastomas in four patients were treated with stereotactic radiotherapy, where four showed complete radiological response and the fifth was static. Neurological symptoms and signs improved in those patients. The sixth haemangioblastoma was situated close to the pituitary and optic chiasm, and was treated with conventionally fractionated external beam radiotherapy. The lesion showed partial response. No complications were noted in this patient group. This series complements and extends the relatively sparse published literature demonstrating that radiotherapy is an effective option for treating haemangioblastomas. Radiosurgery often lends itself particularly well to these discrete lesions allowing highly focused treatment. For patients with multiple and metachronous cerebellar haemangioblastomas as part of the von Hipple-Lindau syndrome, the data support a policy of conventionally fractionated external beam radiotherapy to the whole cerebellum of 50-55 Gy followed, after a period of time, by radiosurgery to persisting lesions (patients 3 and 4).

Adolescent↗
PubMed1997

Stereotactic multiple arc radiotherapy. III--Influence of treatment of arteriovenous malformations on associated epilepsy.

Although radiosurgery obliterates the majority of arteriovenous malformations (AVMs) and cures patients of further haemorrhage, the perceived beneficial effect on the epilepsy associated with it is less certain. Two recent publications suggest that radiosurgery benefits the associated epilepsy. In a consecutive series of 101 AVM patients presenting for radiosurgery to St Bartholomew's Hospital, 24 had a history of fits; 16 were evaluable for analysis of fit control. Fifteen of the sixteen patients (94%) had improvement in fit control, 10/16 (63%) becoming fit free. This improvement appeared to correlate with response to treatment on follow-up angiography and in 11/15 patients this occurred with no change or a reduction in anticonvulsant in medication. No patient suffered a deterioration in the epilepsy. These data are discussed in the context of the only two previous reports in the literature and the mechanisms of action of treatment.

Adolescent↗
PubMed1996

A physiologic approach to bowel training.

Bowel training is an effective management option for many patients with dysfunctional bowel elimination patterns and neurogenic fecal incontinence. To be effective, a bowel training program must be based on sound physiologic principles and must be individualized for each patient. This article includes a review of the structures and physiologic processes controlling normal defecation and the physiologic principles governing bowel training. The steps involved in successful implementation of a bowel training program are discussed, and case studies are used to illustrate the principles.

Adult↗
PubMed1996

Stereotactic multiple arc radiotherapy. II--Cranial neuroma.

We report our early experience using stereotactic radiotherapy (radiosurgery) in the treatment of cranial neuroma, by the linear accelerator method. We report the first 13 neuromas treated in 12 patients (follow-up 6-60 months). Radiologically, seven of 10 patients demonstrated signs of central tumour necrosis on follow-up scanning and four of these also demonstrated shrinkage. Of seven assessable acoustic neuroma patients treated, hearing was stabilized in three and improved in two. An abducent neuroma patient treated by this method is reported and demonstrated good response. Our preliminary studies endorse the opinion that stereotactic radiosurgery is a suitable and safe alternative to microsurgical procedures in the management of many cranial neuromas. Indications for stereotactic radiosurgery are discussed.

Adult↗
PubMed1995

Stereotactic multiple arc radiotherapy. I. Vascular malformations of the brain: an analysis of the first 108 patients.

Between March 1989 and December 1993, 101 patients with inoperable arteriovenous malformations (AVMs) and seven patients with inoperable angiographically occult malformations (AOVMs) have been treated with stereotactic multiple arc radiotherapy (SMART). All patients (excluding one patient with a brain stem AOVM) were treated with a uniform dose of 1750 cGy prescribed to the 90% isodose. Fifty-two patients with AVMs have had follow-up angiographic studies performed 11-42 months after SMART. The complete angiographic obliteration rates were 75-77% for AVMs < 10 cm3 and 40-75% for AVMs > 10 cm3, when studied 18-30 months after SMART. Four patients re-bled prior to complete obliteration representing an actuarial 2-year incidence of re-bleeding of 5.1%. Seven patients developed a new neurological deficit after SMART after a median latent interval of 17 months (range 6-32). The actuarial 2-year incidence of neurological complications was 1.8% for lesions < 10 cm3. The actuarial 2-year incidence of neurological complications was 16% for lesions > 10 cm3 (10.5% for persisting deficit). Of seven patients with AOVM six have shown a reduction in size and degree of contrast enhancement, but in no patient has there been complete resolution shown by CT. Five patients with AOVMs developed symptomatic neurological deterioration at a median of 6 months after SMART (range 5-9). When viewed in the context of the natural history of conservatively managed inoperable AVMs, this series has demonstrated that our highly specialized irradiation technique is a safe and effective treatment for many patients.

Adolescent↗
PubMed1995

External beam radiotherapy for retinoblastoma: II. Lens sparing technique.

A retrospective analysis is presented of the results of external beam radiotherapy for retinoblastoma utilising an accurate lens sparing technique. Local tumour control has been assessed in a consecutive series of 67 eyes in 53 children all of whom received external beam radiotherapy as the primary treatment of retinoblastoma. Follow up ranged from 12 to 82 months (median 35 months) with 76% of the children followed for more than 2 years. Tumour control rates have been analysed with respect to the Reese-Ellsworth classification. The role of adjuvant and salvage focal therapy is emphasised. Following lens sparing radiotherapy with prior adjuvant treatment of anterior tumours, where appropriate, the overall ocular cure rate was 72%. With salvage therapy of persistent, recurrent, or new tumours, 93% of eyes could be preserved in this series which includes mainly eyes classified in Reese-Ellsworth groups I-III. These results compare favourably with those of whole eye external beam radiotherapy for comparable tumours, and with those of lens and anterior segment sparing using other techniques. They were achieved without the ocular morbidity associated with whole eye external beam radiotherapy.

Child↗
PubMed1994

A rational approach to the use of topical antiseptics.

The proper application of antiseptics to the open wound is controversial. With the goal of creating an optimal environment for wound repair, consideration of a topical antiseptic includes both its bactericidal activity and its potential cytotoxicity when applied to the healing wound in varying concentrations. This discussion reviews the events of wound healing, including the key cells that mediate this process, the significance of bacteria in the wound bed, and the impact of infection. Specific antiseptics, including povidone-iodine, hydrogen peroxide, acetic acid, and Dakin's solution are reviewed, emphasizing their bactericidal potential and their cytotoxic properties.

Anti-Infective Agents, Local↗
PubMed1993

Exercise endurance in rats: roles of type I and II corticosteroid receptors.

Intact and adrenalectomized (ADX) rats were mildly food deprived and administered dexamethasone (type II agonist), aldosterone (type I agonist), corticosterone (mixed agonist), or vehicle 24 and 2 h prior to forced exercise in a treadmill. The endurance of intact animals was unaffected by hormone treatments. Adrenalectomy greatly advanced the onset of fatigue, and aldosterone exacerbated the effect of adrenalectomy. Corticosterone improved endurance in ADX rats, and dexamethasone was even more potent in this respect. Aldosterone slowed deprivation-induced weight loss in ADXs, while corticosterone and especially dexamethasone accelerated loss. Thus, endurance was directly related to body weight loss, and presumably to the fuels released by such loss. The results extend the type I-type II functional dichotomy to the delivery of utilizable energy for metabolically active tissues.

Adrenal Glands↗
PubMed1992

Role of the enterostomal therapy nurse in ostomy patient rehabilitation.

Enterostomal therapy (ET) nurses specialize in the management of patients with urinary and fecal diversions, draining wounds and fistulas, fecal and urinary incontinence, and chronic wounds such as pressure ulcers and vascular ulcers. ET nurses have much to offer in the management of patients with cancer. Such nurses play a major role in the rehabilitation of patients undergoing fecal or urinary diversions. Preoperative services include: counseling regarding planned surgical procedure, the impact of an ostomy on the patient's life, and the basics of ostomy management; sexual counseling; and stoma site selection. Postoperatively, the ET nurse instructs the patient and family in ostomy care, dietary and fluid alterations, and ways to incorporate ostomy management into the patient's life. The ET nurse also provides long-term follow-up care in outpatient settings; such care includes ongoing counseling, education, and surveillance for complications requiring medical intervention. ET nurses can recommend appropriate measures to prevent and manage skin breakdown that is related to immobility, friable skin, incontinence, and/or radiation therapy. They also can assist in correcting or containing fecal or urinary incontinence and in cost-effective management of draining wounds and fistulas.

Counseling↗
PubMed1992

Intracranial germ cell tumours: II. The application of a partial transmission block technique to reduce late morbidity.

Craniospinal axis (CSA) irradiation may be associated with significant late sequelae. The recognition of the influence of dose per fraction on late sequelae and the radiosensitivity of germ cell tumours (GCT) led to the adoption of a partial transmission block (PTB) technique for patients with intracranial GCTs. The PTB allows a dose differential between the whole cranium (prophylactic area) and the primary site (high-dose area) throughout the CSA prescription. The PTB technique has been used in four patients, two with germinoma and two with non-germinomatous germ cell tumours (NGGCT). All patients received two courses of primary chemotherapy with at least a partial response prior to CSA irradiation with the PTB and a three-field boost to the primary site. There was no prolongation in the overall treatment time. The use of this 'CNS friendly' radiotherapy technique was straightforward and the potential benefit in reducing late sequelae is discussed using two isoeffect methods.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

An innovative method for neuraxis radiotherapy using partial transmission block technique.

Whole CNS (neuraxis) radiotherapy is an important part of therapy for certain CNS tumours which seed via the CSF. Many, if not the majority, of these predominantly young patients are cured but the neuropsychometric, neuroendocrine and growth morbidity of neuraxis radiotherapy on children by conventional methods may be considerable; patients receiving such therapy at an early age often are eventually in the educationally subnormal category. Recent radiobiological data support the concept that all aspects of CNS radiation tolerance are heavily dependent on daily fraction size. We describe a new radiotherapy technique that allows lower daily fraction sizes to be delivered to the neuraxis without prejudicing the total dose to the neuraxis or primary area and without prolonging the overall treatment time. Published radiobiological data support the concept that all the major morbidities attributed to conventional neuraxis radiotherapy will be reduced by the currently described technique without reducing tumour control rates.

Brain Neoplasms↗
PubMed1990

Stereotactic multiple arc radiotherapy.

A radiotherapy technique is presented for delivering a concentrated pattern of absorbed dose to intracranial lesions. Treatment takes place on a conventional, isocentrically mounted linear accelerator, rotated in several planes around a single target site. A new, relocatable stereotactic frame is used which enables fractionated radiotherapy to be administered if required. Calculations of the absorbed dose distribution in three orthogonal planes are performed using specially prepared software on a computer used for standard treatment planning. In this way, the need for excessive computing power is avoided.

Brain Diseases↗
PubMed1988

Radiotherapy in benign orbital disease. II: Ophthalmic Graves' disease and orbital histiocytosis X.

Ophthalmic Graves' disease and histiocytosis X involving the orbit are occasionally refractory to treatment, so that vision may be threatened. In these situations megavoltage external beam radiotherapy should be employed, and the indications for this treatment are discussed. A highly accurate technique is described, using precise planning with information obtained from high definition CT scans, a complete patient head shell for immobilisation, and modern megavoltage radiotherapy treatment machines. As a result the dose to the lens is minimised (to a maximum of 10% of the prescribed dose), and late morbidity will be small. Two cases are described to illustrate this procedure and the response to treatment.

Adult↗
PubMed1987

Improved total-body irradiation dosimetry.

The total-body irradiation (TBI) technique at St Bartholomew's Hospital has been developed to improve dose homogeneity within the patient. Using a standard 6 MV linear accelerator in an orthodox-sized treatment room, the midpoint doses in head, neck, shoulders, mid-mediastinum, pelvis, knees and ankles are +/- 5% of that of the umbilicus in our current technique. This homogeneity has been achieved by a four-field technique, a reproducible patient set-up, careful use of a new bolus material and an additional beam-flattening filter mounted near the machine head. In addition, thermoluminescent dosimetric data collected at a test irradiation before TBI are used to influence field weightings and further improve dosimetry. This individualised and empirical TBI technique has dosimetric advantages over theoretical TBI dosimetric considerations in reducing dose gradients within the patient. These advantages are discussed.

Data Collection↗
PubMed1985

Combining backscattered electrons and low energy photons to improve the dose distribution to an eyelid.

In electron beam therapy, backscattered electrons from metal shields result in a high dose to tissue in the vicinity of the shield. Data are now available which enable both the magnitude of the dose enhancement at the interface and the fall off in dose 'up stream' to be determined. With the aid of these data, a combined modality therapy (5 MeV electrons, 1.1 mm A1 HVL X rays) was given to an eyelid during which the lens was protected with a superficial X ray lead eye shield. The eyelid was treated to a mid lid dose of 45 Gy in 28 days, and the dose gradient on the beam central axis was more uniform (+/- 3%) than that obtainable with superficial X rays alone. The lens dose from the combined therapy was estimated to be less than 0.25 Gy.

Aged↗