International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2000
Comparison of dose length, area, and volume histograms as quantifiers of urethral dose in prostate brachytherapy.
To determine the magnitude of the differences between urethral dose-volume, dose-area, and dose-length histograms (DVH, DAH, and DLH, respectively, or DgH generically). ⋯ Dose gradients in prostate implants result in the observed ordering of DAH, DVH, and DLH from higher to lower doses. The three histogram approaches remain in close agreement up to 100% of the mPD but diverge at higher doses. Although urethral point doses are the most easily determined, they underestimate the amount of urethra at risk at higher doses compared to dose area analysis. Because dosimetric parameters detailing high-dose regions such as D(10) show only slight differences between calculation methods, they are recommended over the corresponding geometric entities G(150) or G(175). The differences between the D(gg) entities are sufficiently small that they are unlikely to be of clinical significance or to confound analyses attempting to correlate urinary morbidity with urethral dosimetry.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2000
Decreasing the dosimetric effects of misalignment when using a mono-isocentric technique for irradiation of head and neck cancer.
The purpose of this study was to quantify and develop methods to decrease inhomogeneities created with field edge mismatch when using a mono-isocentric beam-split technique. ⋯ The two methods of evaluating matchline dose described above gave similar results. When using the mono-isocentric half-field technique, small misalignments produce worrisome regions of inhomogeneity. Our penumbra generator substantially decreases the magnitude of the dose inhomogeneities, although the volume receiving an inhomogeneous dose increases.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2000
Comparative StudyA comparison of radiation dose to the neurovascular bundles in men with and without prostate brachytherapy-induced erectile dysfunction.
The etiology of erectile dysfunction after definitive local therapy for carcinoma of the prostate gland represents a multifactorial phenomenon including neurogenic compromise, venous insufficiency, local trauma, and psychogenic causes. It has been suggested that impotence after prostate brachytherapy is a consequence of excessive radiation dose to the neurovascular bundles (NVB). Herein we evaluate the potential relationship between radiation dose to the NVB and the development of erectile dysfunction following prostate brachytherapy. ⋯ In this study, no relationship between radiation dose to the NVB and the development of post brachytherapy erectile dysfunction was discernible. Such a difference may become evident with additional follow-up. If long-term brachytherapy-induced erectile dysfunction is related to the radiation dose to the NVB, the ultimate preservation of potency following prostate brachytherapy may be markedly inferior to what has been reported. Nevertheless, the majority of this patient population responded favorably to sildenafil.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2000
The influence of young age and positive family history of breast cancer on the prognosis of ductal carcinoma in situ treated by excision with or without radiation therapy or by mastectomy.
Several recent studies have investigated the influence of family history on the progression of DCIS patients treated by tylectomy and radiation therapy. Since three treatment strategies have been used for DCIS at our institution, we evaluated the influence of family history and young age on outcome by treatment method. ⋯ The most important determinant of outcome was the selection of treatment modality, with all of the recurrences occurring in the tylectomy alone group. In addition to treatment method, a positive family history significantly influenced LRR in patients treated by tylectomy, especially in women 50 years of age or younger. These results suggest that DCIS patients, particularly premenopausal women with a positive family history, benefit from treatment of the entire breast, and raise concerns about treating patients with a possible genetic susceptibility to breast cancer with tylectomy alone.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2000
Comparative StudyThe cost-effectiveness and cost-utility of high-dose palliative radiotherapy for advanced non-small-cell lung cancer.
To compute cost-effectiveness/cost-utility (CE/CU) ratios, from the treatment clinic and societal perspectives, for high-dose palliative radiotherapy treatment (RT) for advanced non-small-cell lung cancer (NSCLC) against best supportive care (BSC) as comparator, and thereby demonstrate a method for computing CE/CU ratios when randomized clinical trial (RCT) data cannot be generated. ⋯ The cost effectiveness and cost utility of high-dose palliative RT for advanced NSCLC compares favorably with the cost effectiveness of other forms of treatment for NSCLC, of treatments of other forms of cancer, and of many other commonly used medical interventions; and lies within the US $50, 000/QALY benchmark often cited for cost-effective care.