Total body irradiation (TBI) is a standard treatment modality within the multidisciplinary approach for allogeneous stem cell or bone marrow transplantation. However, surviving patients are at risk for developing a variety of late sequelae. This analysis aimed to retrospectively characterize late effects after TBI in adults treated in a single center.

PURPOSE: Different doses and techniques used in high-dose-rate (HDR) prostate brachytherapy make it difficult to define universal quality parameters. The aim of this study was to develop individual, objective parameters for the evaluation of an HDR brachytherapy plan for prostate radiation.METHODS: Fifty-three patients who received an HDR brachytherapy boost after external radiation were analyzed in this study. Brachytherapy was performed with a 192 It source after ultrasound-guided, transperineal metal needle application followed by removal of the ultrasound probe to reduce organ dose levels at the anterior rectum wall. The rectum and prostate locations as well as the dose at the anterior rectum wall were estimated under the anatomical conditions of HDR prostate brachytherapy. The doses at the organs at risk (rectum and urethra) were analyzed for several parameters, which were compared to values of former patients before the start of treatment. In cases of major deviations, modifications of the treatment plan were performed before starting the treatment.RESULTS: Deflating of the water balloon led to an increase of the space between the anterior rectal wall and the dorsal margin of the prostate (mean, 6 mm; 1-10 mm). The dose of the introduced "virtual rectum," represented by the ventral surface of the ultrasound probe, in the treatment plan correlated to dose measurements in the rectum. Pretreatment evaluation and comparison of the established individual quality parameters led in two cases to a treatment plan modification.CONCLUSIONS: This method allows a fast and objective individual brachytherapy treatment plan evaluation and improvement. (c) 2007 American Brachytherapy Society. All rights reserved.

BACKGROUND AND PURPOSE:During radiotherapy of localized prostate cancer, organ movements for the dose exposure of organs at risk like rectum, urinary bladder and urethra play, inter alia, a significant role. One possibility of internal organ stabilizing is offered by the usage of a rectal balloon during radiotherapy. The influence on organ movements and dose allocation of the organs at risk is unknown.PATIENTS AND METHODS:Twelve patients (Table 1) were characterized based on planning-CT's regarding organ movements and organ doses using a rectal balloon, inflated with 0 ml and 60 ml air. For the determination of the organ doses, three-dimensional conformal radiation plans (3-field-pelvis box) with a cumulative dose of 59.4 Gy were created, and the dose-volume-histograms for the anterior rectal wall, the posterior rectal wall, the rectal mucosa, the whole rectum, as well as the urinary bladder were compared (Figures 1 and 2).RESULTS:The application of a 60 ml air-filled rectal balloon during each fraction of teletherapy led to significant organ movements of the anterior and posterior rectal wall and to a reduction of the transversal prostate diameter, as well as to a changed organ dose exposure of the organs at risk. A ventral shift of the anterior rectal wall (maximum 0.8 cm, mean 0.4 cm) was shown, as well as a dorsal shift of the posterior rectal wall (maximum 1.2 cm, mean 0.7 cm), associated with a transversal prostate diameter decrease (maximum 0.8 cm, mean 0.3 cm) (Table 2, Figure 3). The organ dose of the anterior rectal wall increased significantly (maximum 1.3 Gy, mean 0.5 Gy) during application of a rectal balloon, the one of the posterior rectal wall decreased significantly (maximum 18.6 Gy, mean 6.5 Gy). Related to the entire rectal mucosa and the rectum as a complete organ, a decrease of the maximum doses was shown (rectal mucosa: maximum 9.1 Gy, mean 3.0 Gy; rectum: maximum 9.4 Gy, mean 3.7 Gy). The organ dose of the urinary bladder did not show significant changes (Tables 3 and 4, Figures 4 to 7).CONCLUSION:The application of a rectal balloon in teletherapy of localized prostate cancer leads to significantly changed dose exposition of organs at risk. The decreased dose exposure of the posterior rectal wall and the rectal mucosa is opposed by the higher organ dose of the anterior rectal wall. It has to be shown weather documented organ dose exposure is associated with short and long-term consequences.

The effect of the sensible heating by the oceans on atmospheric circulation is dealt with in terms of the atmospheric available potential energy (APE) generated by such heating. By using the exact expression for the generation of atmospheric APE one can assess what fraction of this sensible heating is actually effective in producing atmospheric APE. A measure of this efficiency (termed the efficiency factor) was studied. The study showed considerable time and spatial variations in the field of the efficiency factor. It was also shown that many of the oceanic regions that are known to be strong sources of sensible heating produce but little atmospheric APE. Low latitude regions (the Caribbean and Gulf of Mexico especially) are associated with higher efficiencies and hence are most effective in producing available potential energy.

The effect of the sensible heating by the oceans on atmospheric circulation is dealt with in terms of the atmospheric available potential energy (APE) generated by such heating. By using the exact expression for the generation of atmospheric APE one can assess what fraction of this sensible heating is actually effective in producing atmospheric APE. A measure of this efficiency (termed the efficiency factor) was studied. The study showed considerable time and spatial variations in the field of the efficiency factor. It was also shown that many of the oceanic regions that are known to be strong sources of sensible heating produce but little atmospheric APE. Low latitude regions (the Caribbean and Gulf of Mexico especially) are associated with higher efficiencies and hence are most effective in producing available potential energy.