Prostate brachytherapy: comparison of dose distribution with different 125I source designs.

PURPOSE: To evaluate the interchangeability of various commercially available iodine 125 ((125)I) sources and to assess the dosimetric effect of a change in source. MATERIALS AND METHODS: A modified peripherally loading prostate brachytherapy plan to deliver 145 Gy was devised by using a model (125)I source, which until recently was the only available (125)I source. A dose-volume histogram was generated. By using the available radial dose functions and anisotropy distributions for eight other currently commercially available sources, the same implant placement was planned and dose-volume histogram distributions tabulated. This exercise was performed for 15-, 45-, and 60-cm(3) glands. No implants were placed, and no physical radiation measurements were made. Dose calculations were theoretic: They were generated by using a widely available treatment planning system. RESULTS: There was little difference in dose distribution to the volume receiving 100% of the prescribed dose (<6%); only one source showed a difference greater than 2%. Large differences, up to -40% to +60%, were seen in the volume of tissue encompassed within internal high-dose regions receiving 150% or 200% of the prescribed dose. These findings held true, irrespective of gland size, within a clinically relevant range (15-60 cm(3)) and for a uniformly loaded radionuclide distribution. CONCLUSION: Reviewing only peripheral dose at or near the prescription dose of 145 Gy revealed little difference in doses for various source designs. Marked differences in high-dose regions were seen and may affect the dose received by internal sites. Effects of these changes on cure and/or complications remain speculative.

American Brachytherapy Society (ABS) recommendations for transperineal permanent brachytherapy of prostate cancer.

PURPOSE/OBJECTIVE: To develop and disseminate the American Brachytherapy Society (ABS) recommendations for the clinical quality assurance and guidelines of permanent transperineal prostate brachytherapy with 125I or 103Pd. METHODS AND MATERIALS: The ABS formed a committee of experts in prostate brachytherapy to develop consensus guidelines through a critical analysis of published data supplemented by their clinical experience. The recommendations of the panels were reviewed and approved by the Board of Directors of the ABS. RESULTS: Patients with high probability of organ-confined disease are appropriately treated with brachytherapy alone. Brachytherapy candidates with a significant risk of extraprostatic extension should be treated with supplemental external beam radiation therapy (EBRT). Patient selection guidelines were developed. Dosimetric planning of the implant should be carried out for all patients before seed insertion. A modified peripheral loading is preferred. The AAPM TG-43 recommendations requiring a change in prescription dose for 125I sources should be universally implemented. The recommended prescription doses for monotherapy are 145 Gy for 125I and 115-120 Gy for 103Pd. The corresponding boost doses (after 40-50 Gy EBRT) are 100-110 Gy and 80-90 Gy, respectively. Clinical evidence to guide selection of radionuclide (103Pd or 125I) is lacking. Post implant dosimetry and evaluation must be performed on all patients. It is suggested that the dose that covers 90% (D90) and 100% (D100) of the prostate volume and the percentage of the prostate volume receiving the prescribed dose (V100) be obtained from a dose-volume histogram (DVH) and reported. CONCLUSION: Guidelines for appropriate patient selection, dose reporting, and improved quality of permanent prostate brachytherapy are presented. These broad recommendations are intended to be technical and advisory in nature, but the ultimate responsibility for the medical decisions rests with the treating physician. This is a constantly evolving field, and the recommendations are subject to modifications as new data becomes available.

The scientific, quasi-scientific and popular literature on the use of St. John's Wort in the treatment of depression.

St. John's Wort, also known as Hypericum, is an herbal product that is available in health food stores as an allegedly 'safe' alternative to antidepressants developed by the pharmaceutical industry. Recently it has received extensive coverage through the media, especially in the United States. To the best of our knowledge, Germany is the only country where it has been formally approved for clinical use. We reviewed both the vulgar and the scientific literature on this product. Although the few controlled studies that have been conducted pertain to adjustment disorder with depressed mood, several books and the media advocate its use for clinical and/or chronic depression. The high placebo rate in these studies, often in the 50% range, does indeed suggest that the controlled trials have been conducted on mild transient depressions; extrapolation to more serious or chronic depressions would therefore be unwarranted. We could not find any published literature comparing the efficacy of Hypericum to a standard antidepressant versus placebo. Furthermore, the studies claiming safety and freedom from potentially serious side effects appear flawed methodologically. Actually, little is known about the putative mechanism of action of Hypericum in depression; if indeed it does involve serotonergic mechanisms or monoamine-oxidase inhibition, it invites caution with concurrent use with an SSRI and, of course, with a MAOI. A skeptic might conclude that St. John's Wort should not be used until more definitive data are available. A less conservative view would be that, while its current widespread use is not warranted, the product may still have some merit for mild nonchronic depressive states below the clinical threshold. If this were conclusively proven, it would indeed constitute an important development in the field of antidepressants.

[X-ray diagnosis of colorectal carcinoma today--a determination of where we stand]. / Röntgendiagnostik bei kolorektalem Karzinom heute--Eine Standortbestimmung.

Long-term prognosis of this malignant and frequent disease can be improved only by early diagnosis of small polyps and of carcinomas in the early stage. It is necessary to coordinate high-quality colon contrast medium enemas (double-contrast method) and hypotension with coloscopy and endoscopic removal of polyps. If a colon carcinoma is identified, it is additionally also necessary--probably mostly by colon enema--to exclude preoperatively a metachronous second carcinoma which can be expected in about 5% of the cases. Ultrasound and computed tomography will help in visualising advanced carcinomas that have already passed the wall and are borderline cases in respect of operability, as well as in identifying lymph node and liver metastases, besides in identifying complicating local perforations. Proof, however, is only rendered by a positive finding. It will be necessary to determine at what extent magnetic resonance can be useful in this context.

Computed tomography in the differential diagnosis of the enlarged retrorectal space.

The value of computed tomography (CT) in the differentiation of an enlarged retrorectal space was analyzed in 132 cases. Classification of barium enema findings into those with simultaneous mucosal alterations and those without any visible lesions of the rectal mucosa seems to be useful. Computed tomography helps in those cases without mucosal changes to differentiate between retrorectal fibrosis, tumorous masses, and inflammatory diseases of the colon. It also demonstrates the lack of pathologic lesions in equivocal cases of pelvic lipomatosis and so-called "normal variants." If simultaneous mucosal involvement on barium enema--especially in rectal carcinoma or recurrent carcinoma of the rectum--is found, CT may show the perirectal extension of tumorous masses and thus help to clarify local operability.

[When is computed tomography indicated in dilatation of the retrorectal space?]. / Wann ist bei einer Erweiterung des Retrorektalraumes eine Computertomographie indiziert?

The reasonable use of computed tomography in the diagnosis of an enlarged retrorectal space was analysed in 92 cases. CT is useful in differentiation of a pathologically enlarged retrorectal space without mucosal lesions of the rectum. It enables the separation between tumourous masses, proliferation of connective tissue (in retrorectal fibrosis or inflammatory disease) and pelvic lipomatosis. If simultaneous mucosal involvement in barium enema or rectoscopy--especially in rectal carcinoma or recurrent carcinoma of the rectum- is found, CT may show the perirectal extension of tumorous masses and thus help to clarify local operability.

Secondary involvement of the transverse colon by tumors of the pelvis: spread of malignancies along the greater omentum.

Based on selected case studies the pathways of spread of malignancies arising from the pelvis are discussed. Secondary involvement of the transverse colon with characteristic lesions at the inferior border may be seen in these cases, caused by metastatic spread via the greater omentum. Ultrasonography and computed tomography may prove this diagnosis by showing peritoneal metastatic spread and tumorous infiltration of the greater omentum.

[Involvement of the colon in gastric and pancreatic processes]. / Kolonbeteiligung bei Magen- und Pankreasprozessen.

Using representative case studies the diagnostic problems of colonic infiltration in cases of gastric and pancreatic neoplastic or inflammatory lesions are discussed. Typical signs in both barium enema and ultrasonography lead to the detection of secondary bowel wall lesions. Characteristic intraperitoneal pathways of spread and roentgen-morphologic features are important in the attempt to differentiate inflammatory from malignant infiltrations. In these cases ultrasonography, showing a diffuse thickening of gastric or bowel wall, is a useful additional diagnostic tool, which gives further information about topographical relations in the abdomen.

[The enlarged retrorectal space--indicative of specific pathology or only unspecific symptom of disease in the true pelvis? (author's transl)]. / Der erweiterte Retrorectalraum--ein sicher pathologisches oder nur unspezifisches Zeichen einer Erkrankung im kleinen Becken?

The retrorectal space was measured on the lateral view of the rectum during double contrast barium enema examination in 300 patients in whom no abnormality of the rectum, sacrum or in the true pelvis was demonstrated clinically or radiographically. The measurement obtained is the distance between posterior wall of the rectum and the anterior surface of the sacrum between S2 and S5. The measurements at S5 are considered most accurate, since at this level the rectum will be positively in midline. The normal width at S5 is between 0.2 and 1.5 cm. In connection with other symptoms, a distance between 1.5 and 2 cm should be regarded as suspicious and above 1 cm as definitely abnormal, as was demonstrated in 95 cases with diffuse and localized enlargement of the retrorectal space. An abnormal measurement of greater than 2 cm however is an unspecific symptom and should not by itself be considered indicative of specific pathology, but rather should lend supporting evidence to other abnormal findings in the true pelvis.