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Biomedical subjects

R G Richardson

Publications and source records attributed to R G Richardson.

10 recordsLinked to original sources
PubMed1986

Radiotherapy treatment planning using lymphoscintigraphy.

A method for the three dimensional location of lymph nodes with respect to the skin surface is described. The technique is based on the reconstruction of surface shape using isocentric radiographs taken with metal chains draped on the patient. Registration of the radiographic study to the lymphoscintigraphic study is accomplished automatically by matching the location of four radiopaque and radioisotope markers. This method allows nodes to be located in a beam's eye view with any set up of an isocentric radiotherapy machine. An accurate determination of the depth of lymph nodes is obtained, which is of value in electron beam therapy.

Breast Neoplasms↗
PubMed1986

Adjuvant radiotherapy following radical prostatectomy: results and complications.

Between 1954 and 1978, 148 patients underwent radical perineal prostatectomy for adenocarcinoma clinically confined to the prostate gland. This report is based on 45 of these patients with microscopic extension of disease beyond the gland and a minimum 5-year followup. Of the patients 22 received adjuvant external beam radiation therapy and 23 did not. The groups were comparable with regard to significant prognostic variables. Patient selection was by surgeon preference. Local recurrences were seen in 1 of 22 patients (5 per cent) receiving adjuvant radiotherapy and 7 of 23 (30 per cent) undergoing an operation alone (p less than 0.05). Of 8 patients with local recurrence 7 died of the disease. Delayed radiotherapy of a local recurrence generally was not effective in controlling the disease. Of the 11 patients who died of prostatic cancer with a mean followup of 9.2 years 3 received adjuvant radiotherapy and 8 did not. Severe but nonfatal long-term complications were seen in 14 per cent of the irradiated patients and 6 per cent of those treated with an operation alone. Most of the complications occurred in the earlier years of the study in patients who received 60cobalt radiotherapy. When clinical stage B cancer of the prostate is found to be pathological stage C following radical perineal prostatectomy, adjuvant radiotherapy can decrease the incidence of subsequent local recurrence. The potential risk of adjuvant radiation therapy should be weighed and its use considered, particularly in patients whose tumor extends to the surgical margins or who have seminal vesicle invasion.

Adenocarcinoma↗
PubMed1985

A basis for blocking the spinal cord in opposed field irradiation.

The concept of partial tolerance is applied to the equivalent dose formula for spinal cord tolerance to allow for the change in dose when open and blocked fields are used in a course of radiotherapy. The field arrangement considered is parallel opposed irradiation. Certain assumptions are made regarding the contribution of dose to the spinal cord from open and blocked fields, which allows for the development of an equation to calculate the number of fractions that require spinal cord shielding in the posterior field. The use of a form to facilitate these calculations is described.

Humans↗
PubMed1979

Radiation therapy for localized prostate cancer.

Since 1965, 401 patients with prostate cancer have received intensive local pelvic radiation therapy at the Virginia Mason Medical Center. Two hundred seventy-seven of these patients were treated from 1965 through 1975, comprising the study group. Two hundred twenty-one of this series were in the Stage C category. The 36 Stage B cancers were either medically nonoperable, or advanced extent, or had high-grade histopathology. Ten patients each were in diffuse Stage A or Stage D groups, the latter receiving local palliative intensive treatment to the prostate area. The mean age of the patients was 67.6 years. The five year survival of the Stage C group was 57.7%. There was no apparent influence on the survival of irradiated Stage C patients who received estrogen therapy. Current treatment techniques employ 10 megavolt photon beam with whole pelvic nodal fields and bilateral arc rotational boost fields. The incidence of reactions and complications is presented.

Aged↗
PubMed1979

Carcinoma of the prostate: local control with external beam radiation therapy.

Local clinical control of the primary disease was evaluated in 209 patients with stage C adenocarcinoma of the prostate treated with definitive external beam radiation therapy and followed for a minimum of 2 years. Of these patients 92 per cent required no further prostatic operations for obstruction. Prostatectomy before therapy did not necessarily prevent later prostatic obstruction from occurring. Of 129 patients who had only a needle biopsy before irradiation 90 per cent had improvement of the obstructive and/or irritative symptoms as tumor regression occurred with therapy and these patients did not require a later prostatic operation for obstruction. Stricture formation occurred in 8 per cent of the patients and was not influenced by the type of preirradiation prostatic operation done. If transurethral resection was reuqired after irradiation it was technically more difficult but the morbidity was acceptable. The incidence of hematuria and incontinence was far less than that reported in non-irradiated patients with this disease. Most tumors exhibited a down-grading effect after irradiation. There were no deaths attributable to the treatment. Over-all, 83 per cent of the 209 patients had no urinary complaints after completion of therapy. From a urological viewpoint, good clinical local control is achieved in the patient with stage C adenocarcinoma of the prostate treated with external beam radiation therapy.

Adenocarcinoma↗