International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Prostate gland motion assessed with cine-magnetic resonance imaging (cine-MRI).
To quantify prostate motion during a radiation therapy treatment using cine-magnetic resonance imaging (cine-MRI) for time frames comparable to that expected in an image-guided radiation therapy treatment session (20-30 min). ⋯ Motion of the prostate and seminal vesicles during a time frame similar to a standard treatment session is reduced compared to that reported in interfraction studies. The most significant predictor for intrafraction prostate motion is the status of rectal filling. A prostate displacement of <3 mm (90%) can be expected for the 20 min after the moment of initial imaging for patients with an empty rectum. This is not the case for patients presenting with full rectum. The determination of appropriate intrafraction margins in radiation therapy to accommodate the time-dependent uncertainty in positional targeting is a topic of ongoing investigations for the on-line image guidance model.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Comparative StudyA permanent breast seed implant as partial breast radiation therapy for early-stage patients: a comparison of palladium-103 and iodine-125 isotopes based on radiation safety considerations.
A permanent breast seed implant (PBSI) technique has been developed as a new form of partial adjuvant radiation therapy for early-stage breast cancer. This study compares iodine-125 ((125)I) and palladium-103 ((103)Pd) isotopes by examining the exposure and effective dose (ED) to a patient's partner. ⋯ PBSI using (103)Pd seeds appears safe because the patient's partner ED is consistently below 5 mSv. The(125)I isotope is not recommended for PBSI.
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To evaluate erectile function after permanent prostate brachytherapy using a validated patient-administered questionnaire and to determine the effect of multiple clinical, treatment, and dosimetric parameters on penile erectile function. ⋯ Using a patient-administered validated quality-of-life instrument, brachytherapy-induced ED occurred in 50% of patients at 3 years. On multivariate analysis, preimplant erectile function and the D(50) to the proximal crura were the best predictors of brachytherapy-related erectile function. Because the proximal penis is the most significant treatment-related predictor of brachytherapy-related ED, techniques to minimize the radiation dose to the proximal penis may result in improved rates of potency preservation.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Benefit of respiration-gated stereotactic radiotherapy for stage I lung cancer: an analysis of 4DCT datasets.
High local control rates have been reported with stereotactic radiotherapy (SRT) for Stage I non-small-cell lung cancer. Because high-dose fractions are used, reduction in treatment portals will reduce the risk of toxicity to adjacent structures. Respiratory gating can allow reduced field sizes and planning four-dimensional computed tomography scans were retrospectively analyzed to study the benefits for gated SRT and identify patients who derive significant benefit from this approach. ⋯ The use of "standard population-based" margins for SRT leads to unnecessary normal tissue irradiation. The risk of toxicity is further reduced if respiration-gated radiotherapy is used to treat mobile tumors. These findings suggest that gated SRT will be of clinical relevance in selected patients with mobile tumors.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Anal canal carcinoma: early-stage tumors < or =10 mm (T1 or Tis): therapeutic options and original pattern of local failure after radiotherapy.
To investigate the clinical history, management, and pattern of recurrence of very early-stage anal canal cancer in a French retrospective survey. ⋯ Most recurrences occurred after a long disease-free interval after treatment and often outside the initial tumor site. These small anal cancers could be treated by RT using a small volume and moderate dose (40-50 Gy for subclinical lesions and 50-60 Gy for T1).