International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2000
Radiotherapy of prostate cancer with or without intensity modulated beams: a planning comparison.
To evaluate whether intensity modulated radiotherapy (IMRT) by static segmented beams allows the dose to the main portion of the prostate target to escalate while keeping the maximal dose at the anterior rectal wall at 72 Gy. The value of such IMRT plans was analyzed by comparison with non-IMRT plans using the same beam incidences. ⋯ IMRT significantly increases the ratio of TCP over NTCP of the rectum in the treatment of prostate cancer. However, constraints for TDI are needed, because a high degree of TDI reduced minimal target dose. IMRT improved uncomplicated local control probability. In our department, IMRT by static segmented beams is planned and delivered in a cost-effective way. IMRT-lim has replaced non-modulated conformal radiotherapy as the standard treatment for prostate cancer.
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To evaluate prognostic factors for medulloblastoma. ⋯ Stage M0 + M1 was the most powerful favorable prognostic factor. In Saudi Arabia more patients present with advanced disseminated disease, 41% M2 + M3, than in the West, and this impacts adversely on overall survival. Total resection and standard radiation treatment were not sensitive prognostic factors in a treatment environment in which 78% of patients underwent at least 90% tumor resection and 60% received standard radiation treatment. In order to improve the proportion of patients able to complete radiation treatment, consideration should be given to limiting resection when the attainment of total resection is likely to be morbid, and to delaying rather than omitting radiation treatment in the patient severely compromised postoperatively.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2000
Comparative StudyThree-dimensional conformal therapy or standard irradiation in localized carcinoma of prostate: preliminary results of a nonrandomized comparison.
We present preliminary results of a nonrandomized comparison of three-dimensional conformal radiation therapy (3D CRT) and standard radiation therapy (SRT) in localized carcinoma of the prostate in two groups of patients with comparable prognostic factors treated during the same period. ⋯ Three-dimensional CRT spares more normal tissues, yields higher chemical disease-free survival, and results in less treatment morbidity than SRT in treatment of Stage T1-T2 prostate cancer. Longer follow-up is needed to confirm these preliminary observations.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2000
Dosimetric evaluation of abutted fields using asymmetric collimators for treatment of head and neck.
The objective of this study was to reevaluate the dose nonuniformity of abutted fields defined using asymmetric collimators and one isocenter for treatment of the head and neck region. ⋯ Imperfect abutment of split fields due to digital display tolerance (+/-1 mm) of asymmetric collimator can cause an underdose or overdose of 15% of the delivered dose.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2000
Defining the appropriate radiation dose for pretreatment PSA < or = 10 ng/mL prostate cancer.
To investigate whether a dose response exists for biochemical no evidence of disease (bNED) control in prostate cancer patients with pretreatment prostate-specific antigen (PSA) < or = 10 ng/mL and to identify the patient subgroups affected. ⋯ The poor prognosis subset of PSA < or =10 ng/mL prostate cancer patients benefit from dose escalation. A dose response is not demonstrated for prostate cancer patients with pretreatment PSA < or =10 ng/mL and other favorable features.