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Results for “Radiotherapy Dosage”

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At least 19 recordsLinked to original sources
PubMed1979

The direct use of CT numbers in radiotherapy dosage calculations for inhomogeneous media.

Techniques by which the quantitative anatomical data inherent in a CT scan can be directly used in treatment planning are described. The correction algorithms used in the RAD-8 system, based on an effective path length, have been extended to a pixel-by-pixel approach. By calibrating the X-ray transmission CT scanner in terms of electron densities (electron cm-3) inhomogeneity corrections may be made automatically.

Humans↗
PubMed1978

Dosimetry for tangential chest wall irradiation.

The skin-sparing effect of megavoltage photons is lost to a varying extent when tangential beams are used to irradiate the chest wall. The skin dose for this technique, with and without a bolus, was investigated for 4- and 6-MV photons using film, thermoluminescent dosimeters, and an ionization chamber. Metal/tissue interface effects were observed when a flexible brass fabric material was used as a bolus.

Humans↗
PubMedDate not supplied

Treatment of radiation-induced alopecia.

Radiotherapy is frequently employed in the management of head and neck neoplasia, either as an adjunct to surgery or as the sole treatment modality. Consequently, radiation alopecia--a well-known complication of high-dosage radiotherapy--is seen often. Longer patient survival, especially with earlier discovery of the malignancy and more refined treatment regimens, will provide the surgeon with the opportunity to treat radiation alopecia by means of the punch graft technique of hair transplantation. The technique is substantially similar to that employed in treating male pattern baldness, although the approach to the recipient and donor areas must be modified. A successful case report is documented and a modified approach is highlighted.

Adult↗
PubMed1975

Combined modality therapy for intracranial tumors.

Three types of tumor (supratentorial astrocytoma, medulloblastoma, and craniopharyngioma), each requiring a fundamentally different therapeutic approach, will be used to illustrate the principles and practice of combined treatment in this field. The role of radiotherapy and ways of enhancing the effect of irradiation will be considered. Attention will be given to adjuvant chemotherapy and to multiple drug regimes. Reference will be made to an early effort at immunotherapy following the initial reduction of tumor cell load by surgery and irradiation.

Antigens, Neoplasm↗
PubMed1977

Radiation treatment planning.

Radiation treatment planning has developed into a substantial and effective component of the entire radiation treatment approach. Over the last 2 decades, with the development of high energy electron and x-ray sources, and also with the availability of new radionuclides and techniques for internally applied radiation, all of which permit a high degree of concentration of radiation, treatment planning has been developed to make best use of these modalities. The use of automatic computation has proved necessary in order to handle the large amounts of radiation data involved in treatment dose calculation. Tumor and anatomical localization has been carried out with increasing precision. Several cases are described which illustrate planning and in particular the use of computerized transverse tomography. The use of moving shadow-shields is also described. For internally applied radiation, the features of iodine-125 are illustrated.

Adult↗
PubMed1977

High-energy photon and electron beam.

The optimum radiation treatment plan for any given clinical situation can be achieved by combining various irradiation modalities and beam energies. The availability of equipment that provides photon and electron beams of energies from 4 MeV to 25 MeV permits optimal dose distribution throughout the treatment volume. Since no difference in the biological effectiveness of electrons compared with megavoltage photons has been demonstrated in laboratory studies, there is no hesitation in combining electrons with photons. The selection of the various energies, the combination of electrons with photons, and the ratio of the given doses of each beam depend on the location of the tumor and the maximum depth to be treated. With the use of one beam alone, a combination of 25 MeV and 4 to 6 MeV photon beams, or a combination of photons and electrons, the most effective treatment plan with the available beams can be designed for any clinical situation.

Adult↗
PubMed1977

Radiation in bone sarcomas: a re-evaluation in the era of intensive systemic chemotherapy.

We have reviewed the literature and described experience in treating Ewing's sarcoma and osteosarcoma before and during the era of intensive systemic chemotherapy. Local control of Ewing's sarcoma may relate to increasing doses of radiation, especially when intensive chemotherapy is administered also. Problems of radiation enhancement by chemotherapy have caused us to reconsider time-dose and volume parameters in treating these patients. The role of radiation in osteogenic sarcoma is limited to patients with inoperable lesions and metastases.

Bone Neoplasms↗
PubMed1977

The increasing importance of radiation therapy in the improved prognosis of children with Wilms' tumor.

Treatment results for 32 children with Wilms' tumor seen at the JCRT, CHMC and SFCI from January 1, 1971, through December 31, 1975, are presented. Indications for and technical details of irridation are discussed. The uniform efficacy of irradiation in preventing local relapse in all patients presenting with unilateral disease despite tumor spill in nine is stressed. Actuarial survival of nearly 80% of all patients seen and followed for more than 2 years has been achieved. Eight of 14 patients with documented pulmonary relapse have been controlled with irradiation, chemotherapy and surgery. The importance of an aggressive multidisciplinary approach to this tumor is stressed.

Child↗
PubMed1977

Soft part tumors.

Results of management of rhabdomyosarcoma of childhood have improved in a dramatic manner during the recent 10 years as a consequence of the treatment by three modality approach which relies on an intensive multi-drug multicycle chemotherapy regimen combined with radiation therapy and or surgery. Both local results and total disease-free survival rates are markedly better with this more comprehensive approach. A staging system for sarcoma of soft tissue has just been developed by the A.J.C. Histopathological grade is the important parameter: stage 1,2, and 3 are tumors of histological grades 1, 2, and 3 respectively (an outline of the system is presented). Treatment results of 100 patients with sarcoma of soft tissue (extremities 89, torso 11) treated by radical dose radiation therapy (less than 6300 rad) and limited surgery at M.D. Anderson Hospital are presented. For both local control and disease free survival, results decreased with advancing stage and anatomic site was not a factor per se. Radiation therapy under tourniquet induced hypoxia was not found to be significantly more effective than conventional radical dose therapy. The necessity of planning treatment such that if subsequent surgery is required, the fields will provide the best distribution of unirradiated or low dose tissue for preparation of flaps, etc.

Adult↗
PubMed1977

Radiotherapy in Hodgkin's disease: past achievements and future progress.

Improvements in results of treatment for Hodgkin's disease have been dramatic in the last 20 years. The results of high dose radiation therapy are reviewed in terms of the importance of the extent of the field of irradiation. The importance of adjuvant chemotherapy is also discussed. Problem areas both in staging and in general management of patients with Hodgkin's disease are emphasized. Long-term complications of treatment, both radiotherapeutic and chemotherapeutic are stressed. The excellent results of management for stage I, II (A and B), and IIIA Hodgkin's disease have reached a level at which future studies must aim at reducing the morbidity of treatment.

Antineoplastic Agents↗
PubMed1977

Radiation oncology: cancer of the prostate.

The role of palliative radiation treatment of prostate cancer is well recognized. Appreciation of the value of definitive radiation therapy in management of locally advanced prostate cancer is increasing. Optimal management requires careful patient selection with multidiscipline evaluation to provide accurate grading and staging, availability of adequate facilities, and careful planning the treatment. Definitive radiation therapy may be used as primary treatment, or in management of endocrine treatment failure, and in postoperative residual or recurrent cancers. Similar techniques may be employed in the management of locally symptomatic Stage D cancer. Definitive radiation therapy is useful management of some Stage B and many Stage C locally advanced and nonresectable cancers of the prostate.

Aged↗
PubMed1977

Radiotherapy and rectal cancer.

Studies utilizing preoperative radiotherapy as an adjunct to surgery are reviewed, with results indicating marked increase in survival. Results of postoperative irradiation also appear beneficial, although less extensive data are available. Irradiation for inoperable and recurrent rectal cancer has demonstrated symptomatic relief, particularly avoidance of colostomy, and can render some patients operable and resectable. Adjuvant immunotherapy after irradiation and operation is suggested for further research.

Clinical Trials as Topic↗
PubMed1977

Radiation therapy as initial treatment for early stage cancer of the breast without mastectomy.

This report describes 150 patients with clinical stage I and II carcinoma of the breast treated at four institutions--Yale University School of Medicine, Harvard Medical School-Joint Center for Radiation Therapy, Hahnemann Medical College, Jefferson Medical College--with radiotherapy only following excisional biopsy. Closely similar treatment policies were followed at all four centers, 4500-5000 rads minimum tumor dose being delivered to the entire breast and axillary, supraclavicular and internal mammary nodes. Forty-six of 49 stage I patients treated are alive without disease, the actuarial relapse-free survival being 91% at 5 years. Of the 101 stage II patients, 75 are alive without disease with a relapse-free actuarial survival of 60% at 5 years. Local failure has occurred in 10 patients (9 stage II and 1 stage I, 6.6%) 5 of whom are disease-free following mastectomy. The results obtained in this study are comparable to those of conventional surgery. It is our conclusion that mastectomy is not a necessary part of the treatment of small breast cancers, that radiation without mastectomy is an acceptable alternative with far superior cosmetic and functional results. Adjuvant chemotherapy should be considered particularly in stage II patients in view of their 40% relapse rate.

Antineoplastic Agents↗
PubMed1977

Radiotherapy in the postoperative treatment of operable cancer of the breast. Part I. Critique of the clinical and biometric aspects of the trials.

A statistical assessment of several "randomized" clinical trials was carried out and the following conclusions were noted. 1. There is no statistically significant evidence that radiation to the peripheral lymphatics and/or chest wall following radical mastectomy affects survival. 2. There is significant evidence that postoperative irradiation to the peripheral lymphatics and/or chest wall does decrease local recurrence rate. 3. There is reliable evidence that the treatment of local recurrence, once it develops, is successful in only 50% of the cases. 4. There is evidence that radiation plus simple mastectomy is as effective in the treatment of breast cancer as radical mastectomy alone. It is our considered opinion that radiation remains a useful adjuvant and complementary agent in the treatment of breast cancer, is not harmful vis a vis survival and should be used when and where indicated.

Adult↗
PubMed1977

Carcinoma of the cervix: present status and future.

The incidence of invasive carcinoma of the cervix is decreasing in Puerto Rico and Continental U.S.A. This appears to be related to improvements in socioeconomic level and adequate utilization of the Pap smear in the population. Mortality from carcinoma of the cervix has shown a 60% reduction in the last 20 years. Most likely this is related to the observed reduction in the incidence of the invasive forms of the disease, earlier diagnosis, and improvements in therapy. Optimal therapy of the clinically evident invasive forms of the disease is a combination of external irradiation and intracavitary brachytherapy. Surgery would be of value for specific clinical situations as an adjuvant to irradiation (barrel-shaped types), in post-irradiation recurrences, inadequate brachytherapy, etc. The yield in terms of survival and disease-free status in the pelvis is high for the early stages of the disease (approximately 90% 5-year survival and 97% control of pelvic tumor for stage I), but stage IIIB and IV cases show a failure rate of close to 50% or more in the irradiated volume and a high incidence of metastases to the para-aortic nodes and elsewhere.

Adult↗