International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Investigation of hypersensitivity to fractionated low-dose radiation exposure.
Hypersensitivity to cell killing of exponentially growing cells exposed to X-rays and gamma rays has been reported for doses below about 0.5 Gy. The reported results have been interpreted to suggest that a dose of 0.5 Gy or less is not sufficient to trigger an inducible repair mechanism. The purpose of this study was to examine this suggested hypersensitivity after multiple low doses (0.3 Gy) of gamma rays where a) the effect would be expected to be significantly magnified, and b) the effect might be of clinical relevance. ⋯ These experiments were specifically designed to magnify and probe possible clinical implications of proposed "low-dose hypersensitivity" effects, in which significant deviations at low doses from the LQ model have been suggested. In fact, the results at low doses per fraction were consistent with LQ predictions based on higher dose per fraction data. This finding is in agreement with the well-documented utility of the LQ approach in estimating isoeffect doses for alternative fractionation schemes, and for brachytherapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Smart (simultaneous modulated accelerated radiation therapy) boost: a new accelerated fractionation schedule for the treatment of head and neck cancer with intensity modulated radiotherapy.
To report the initial experience in the definitive treatment of head and neck carcinomas using SMART (Simultaneous Modulated Accelerated Radiation Therapy) boost technique. Radiation was delivered via IMRT (Intensity Modulated Radiotherapy). The following parameters were evaluated: acute toxicity, initial tumor response, clinical feasibility, dosimetry and cost. ⋯ SMART boost technique is an accelerated radiotherapy scheme that can be delivered with acceptable toxicity. It allows parotid sparing as evidenced both clinically and by dosimetry. Initial tumor response has been encouraging. It is clinically feasible and cost saving. A larger population of patients and a long-term fol
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
High dose rate transperineal interstitial brachytherapy for cervical cancer: high pelvic control and low complication rates.
To report the clinical outcome for cervical carcinoma treated with external beam pelvic radiotherapy and interstitial high dose rate (IS-HDR) brachytherapy. ⋯ We report excellent local and regional pelvic control results using a 6 fraction IS-HDR brachytherapy protocol for cervical carcinoma. The incidence of severe complications is low and suggests that a consistent brachytherapy technique and multiple HDR fractions are therapeutically advantageous to patients treated for cervical carcinoma.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Urinary morbidity following ultrasound-guided transperineal prostate seed implantation.
To assess the urinary morbidity experienced by patients undergoing ultrasound-guided, permanent transperineal seed implantation for adenocarcinoma of the prostate. ⋯ TPIPB is well tolerated but associated with mild to moderate urinary morbidity. Pretreatment prostatic volume and AUA scoring were shown to significantly predict for grade 2 toxicity while the use of preimplant, pelvic XRT and isotope selection did not. Patients undergoing TURP for protracted symptoms following TPIPB did well with a 17% risk of developing stress incontinence. V150 did not help identify patients at risk for urinary morbidity. As transperineal prostate implantation is used more frequently the associated toxicities and the definition of possible pretreatment prognostic factors is necessary to
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Mature results of a pilot study of pelvic radiotherapy with concurrent continuous infusion intra-arterial 5-FU for stage IIIB-IVA squamous cell carcinoma of the cervix.
To evaluate the long-term results of continuous infusion intra-arterial 5-fluorouracil (CI IA 5-FU) given with concurrent pelvic radiotherapy (RT) for FIGO stage IIIB-IVA carcinoma of the cervix. ⋯ While this series is small, the fact that 4 patients with massive Stage IIIB tumors survived after a total radiation dose of only 50 Gy suggests that RT with CI IA 5-FU deserves further study. Modifications in dose, technique, and route of administration should reduce toxicity, and the addition of intracavitary RT should improve the local effectiveness of combined treatment.