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During the last three decades, 3D imaging as X-ray computerised tomography and magnetic resonance imaging was introduced to characterise tumour morphology for an improved delineation of the gross target volume and the clinical target volume. At present, the time has come to also start the assessment and correction of the temporal changes of the target volume. This is the basis of ‘image-guided radiotherapy’ (IGRT), which is characterised by the integration of 2D and 3D imaging modalities into the radiotherapy workflow. The vision is to detect deformations and motion between radiotherapy fractions (inter-fractional IGRT) and during beam delivery (intra-fractional IGRT). Another challenge in radiotherapy is to develop concepts to include and integrate biological imaging into radiotherapy, first by extending the morphological towards a biological planning target volume and second by delivering appropriate inhomogeneous dose distributions, e.g. with the new tools of photon- and particle- Intensity Modulated Radiotherapy (IMRT) techniques (‘dose painting’). [ABSTRACT FROM PUBLISHER]

The importance of exact patient positioning in radiation therapy increases with the ongoing improvements in irradiation planning and treatment. Therefore, new ways to overcome precision limitations of current positioning methods in fractionated treatment have to be found. The Department of Medical Physics at the German Cancer Research Centre (DKFZ) follows different video-based approaches to increase repositioning precision. In this context, the modular software framework FIVE (Fast Integrated Video-based Environment) has been designed and implemented. It is both hardware- and platform-independent and supports merging position data by integrating various computer-aided patient positioning methods. A highly precise optical tracking system and several subtraction imaging techniques have been realized as modules to supply basic video-based repositioning techniques. This paper describes the common framework architecture, the main software modules and their interfaces. An object-oriented software engineering process has been applied using the UML, C + + and the Qt library. The significance of the current framework prototype for the application in patient positioning as well as the extension to further application areas will be discussed. Particularly in experimental research, where special system adjustments are often necessary, the open design of the software allows problem-oriented extensions and adaptations. [ABSTRACT FROM AUTHOR]

Presents a study that assessed the use of two-dimensional polyacrylamide gel electrophoresis for target discovery in human colorectal cancer. Purification of epithelial cells; Analysis of the intratumoral phenotypic heterogeneity of the samples; Examination of the differential expression of paired left colonic tumoral and normal samples.

Presents abstract of several studies on technology and health care. Information on territorial health information system; Development of an Internet-based integrated information planning system for radiotherapy; Research on a structured health resource guide in the Internet.

Background: Radiobiological and physical examinations suggest clinical advantages of heavy ion irradiation. We report the results of 23 women and 22 men (median age 48 years) with skull base tumors irradiated with carbon ion beams at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt, from December 1997 until September 1999.Patients and Methods: The study included patients with chordomas (17), chondrosarcomas (10) and other skull base tumors (Table 1). It is the first time that the intensity-controlled rasterscan-technique and the application of positron-emission tomography (PET) for quality assurance was used. All patients had computed tomography for three-dimensional-treatment planning (Figure 1). Patients with chordomas and chondrosarcomas underwent fractionated carbon ion irradiation in 20 consecutive days (median total dose 60 GyE). Other histologies were treated with a carbon ion boost of 15 to 18 GyE delivered to the macroscopic tumor after fractionated stereotactic radiotherapy (median total dose 63 GyE).Results: Mean follow-up was 9 months. Irradiation was well tolerated by all patients. Partial tumor remission was seen in 7 patients (15.5%) (Figure 2). One-year local control rate was 94%. One patient (2.2%) deceased. No severe toxicity and no local recurrence within the treated volume were observed.Conclusion: Clinical effectiveness and technical feasibility of this therapy modality could clearly be demonstrated in our study. To evaluate the clinical relevance of the different beam modalities studies with larger patient numbers are necessary. To continue our project a new heavy ion accelerator exclusively for clinical use is planned to be constructed in Heidelberg. [ABSTRACT FROM AUTHOR]

Background: In clinical practice it sometimes happens that with currently available conformal radiotherapy techniques no satisfactory dose distribution can be achieved. In these cases inverse radiotherapy planning and intensity modulated radiotherapy may give better solutions.Method: Inverse planning is a technique using a computer program to automatically achieve a treatment plan which has an optimal merit. This merit may either depend on dose or dose-volume constraints like minimum and maximum doses in the target region or critical organs, respectively, or biological indices like the complication free tumor control rate. As the result of inverse planning the inhomogeneous intensity fluence of the beams is calculated. These fluence distributions may be generated by beam compensators or multi-leaf collimation.Results: Clinical studies to prove the advantage of inverse planning are already on the way. It has been shown that this technology is safe and that the dose distributions which can be achieved are superior to conventional methods.Conclusions: Inverse treatment planning and intensity modulated radiation therapy will almost certainly come to be the technique of choice for selected clinical cases. [ABSTRACT FROM AUTHOR]

Background: Stereotaxy is a method to determine a point in the patient's body by an external coordinate system which is attached to the patient. Radiosurgery uses this method for precise delivery of a high single radiation dose to the patient. The aim is to destroy the tissue in the target and to spare surrounding unaffected normal tissue by a steep dose gradient.Methods: Three techniques of percutaneous radiosurgery are available: radiosurgery with ion beams with a cyclotron, spherical arrangement of cobalt-60 sources, the so-called gamma knife, and an adapted linear accelerator. The availability and the good clinical experience lead to a wide spread use of linear accelerator for radiosurgery in recent years. A subsequent development is fractionated stereotactic radiotherapy which combines the precision of radiosurgery with the radiobiological advantage of fractionation.Results: Only a few indications for radiosurgery are proven by statistically valid studies. One of these is the treatment of small arteriovenous malformation, where obliteration rates of 80% to 100% are reported with only minor toxicity. However, the obliteration rate is reduced significantly in large arteriovenous malformations. A local control rate of 90% is obtained after radiosurgery of brain metastases which is comparable to the results of microsurgical resection followed by adjuvant whole brain radiotherapy. An ongoing EORTC study evaluates the role of adjuvant whole brain radiotherapy after radiosurgery. The survival of the patients with brain metastases is limited by the existence of progressive extracerebral disease. The role of radiosurgery in the treatment of benign tumors is currently evaluated in clinical studies which include: vestibular schwannomas, meningiomas, chordomas and chondrosarcomas and pituitary adenomas. Most of the published studies include only small tumors because radiosurgery is limited by the risk of radionecrosis of adjacent normal tissue, which shows a steep dose volume response relationship. Recent developments of stereotactic radiotherapy include the use of mini-multileaf-collimators and clinical studies on stereotactic radiotherapy of extracranial targets.Conclusions: Stereotactic irradiation is a well established treatment technique for intracranial tumors and arteriovenous malformations. Methods are available that allow optimization of dose distributions to irregularly shaped tumors for single dose as well as fractionated stereotactic irradiations by linear accelerator. Therefore the therapeutic potential of this technique has increased and enables also the extracerebral application in controlled clinical studies. [ABSTRACT FROM AUTHOR]

OBJECTIVE Hormone replacement therapy (HRT) is usually prescribed as medium- to high-dose formulations. Little is known, however, about dose-dependency of oestrogen effects on plasma hormone levels, markers of cardiovascular risk in lipid metabolism and the haemostatic system, or markers of bone turnover. SUBJECTS AND DESIGN In an open trial, three groups of 12 or 13 healthy, non-obese postmenopausal women received conjugated equine oestrogens (CEE) for 6 months at doses of 0.3 mg/day (group 1), 0.6 mg/day (group 2) or 1.25 mg/day (group 3). From day 1 to day 10, CEE was administered alone, and from day 11 to day 21, in combination with 5 mg of medrogestone. Each treatment cycle was followed by a pause of 7 days. Fasting blood samples were obtained before treatment as well as on days 10, 21 and 28 of the first, third and sixth months on treatment. All results obtained on day 10 were grouped together as phase A, on day 21 as phase B, and on day 28 as phase C. MEASUREMENTS Plasma concentrations of oestradiol (E), dehydroepiandrosterone sulphate (DHEA-S), total testosterone (T), FSH, PRL, sex hormone binding globulin (SHBG), type I procollagen propeptide (PICP) and the cross-linked carboxyterminal telopeptide of type I collagen (ICTP), total cholesterol, HDL-cholesterol, triglycerides (TG), apolipoprotein (apo) A-1, apo B, lipoprotein(a)[Lp (a)], fibrinogen, factor VIIc and plasminogen activator inhibitor 1 (PAI-1) were evaluated with commercially available kits. RESULTS Dose-dependently, the three regimens increased E, SHBG and factor VIIc activity and decreased FSH, DHEAS, cholesterol, LDL-cholesterol and apoB. HDL-cholesterol and apoA-1 were slightly decreased in group 1 but increased in groups 2 and 3. The high CEE dosage in group 3 resulted in a significant increase of TG and decrease of Lp(a) and PAI-1. Markers of bone turnover were not significantly changed by any CEE dosage. CONCLUSIONS Six months of treatment with 0.3 mg/day of conjugated equine oestrogen significantly lowers serum levels of total cholesterol and LDL-cholesterol without causing the adverse increases of triglycerides or factor VIIc, which were observed at higher doses. However, this low-dose treatment did not yield the maximal LDL-cholesterol lowering effect. Moreover, the positive effects of HRT on HDL-cholesterol, apolipoprotein A-I, lipoprotein (a) and plasminogen activator inhibitor-1 required at least the medium dose of 0.6 mg conjugated equine oestrogens per day. Therefore, further studies are needed to determine which dose of conjugated equine oestrogens has the optimal effect on cardiovascular risk and bone turnover. [ABSTRACT FROM AUTHOR]

A survey of novel microscopic approaches for structural and functional analysis of subnucleolar compartments will be presented. Research on nucleolar structure and function concentrates predominantly on two distinct types of nucleoli: (1) nucleoli present during the interphase of the cell cycle in somatic tissue culture cells and (2) nucleoli present in meiotic cells, e.g. oocytes of amphibians. These nucleoli are found during meiotic prophase of oogenesis and are functional during several months of the diplotene stage of oogenesis. A further characteristic is the fact that these nucleoli are extra-chromosomal, since they originate by selective ribosomal DNA (rDNA) amplification during the early pachytene stage of oogenesis. Miller-type chromatin spread preparations using transcriptionally active nucleoli, to a major part, contributed to our undertanding of the structural organization of polymerase I directed pre-rRNA transcription. Although the structural organization of the template-associated pre-rRNA transcript is known in some detail from chromatin spreads, relatively little is known about structural aspects of pre-rRNA processing. In order to investigate this intriguing question in more detail, we have developed a computer-based densitometry analysis of both template-associated and template-dissociated pre-rRNA transcripts in order to follow the structural modification of pre-rRNA transcripts during processing. Another line of experiments is devoted to the in situ structure of actively transcribing genes in the nucleolus. In order to bridge the gap between light microscopy and electron microscopy we started video-enhanced light microscopical analysis of actively transcribing genes. Although the dimensions of individual spread genes are critical for detection by optical microscopy, we succeeded in obtaining the first series of images of transcribing genes in their 'native' hydrated state. An additional promising type of microscopy is transmission X-ray microscopy. Recent progress in instrumentation as well as in sample preparation has allowed us to obtain the first images of density distribution within intact, fully hydrated nucleoli using amplitude-contrast and/or phase-contrast X-ray microscopy of non-contrasted, fully hydrated nucleoli at different states of transcriptional activity. Whereas the above mentioned investigations using video microscopy and X-ray microscopy are predominantly applicable to the analysis of amplified nucleoli in amphibian oocytes, which are characterized by an extremely high transcription rate of 80-90% of rDNA genes per individual nucleolus, structural analysis of the in situ arrangement of actively transcribing genes in somatic nucleoli as present in the interphase nucleus is far more difficult to perform, mainly due to the much lower number of simultaneously transcribed active genes per individual nucleolus. Visualization of actively transcribed gene clusters is approached by an integrated experimental assay using video microscopy, confocal laser scan microscopy, and antibodies against specific nucleolar proteins. [ABSTRACT FROM AUTHOR]

The basis for most laser applications in neurosurgery is the conversion of laser light into heat when the incident laser beam is absorbed by the tissue. Irradiation of neural tissue with laser light therefore leads to its thermal damage. However, due to the diffusion of heat energy into the surrounding tissue, often there is thermal damage to neural tissue outside the area of the target volume. These are the characteristics of thermal laser/tissue interaction. In this paper we discuss how we used three different short-pulsed lasers to achieve non-thermal ablation of neural tissue. Three different short-pulsed lasers were used to generate ultrashort laser pulses in the picosecond to femtosecond range. The interaction of such laser pulses with tissue was predicted to be nonthermal. The short-pulsed lasers were used for the ablation of neural tissue using an in vitro calf brain model. The histopathological examination of the lesions revealed that the neural tissue had been removed very precisely without any sign of thermal damage to the surrounding tissue. [ABSTRACT FROM AUTHOR]

On the base of a stereotactic device originally described by Riechert and Mundinger a three-dimensional localization and treatment planning system for CT-guided computer assisted stereotactic procedures has been developed. The experience with 338 patients, in which image guided stereotaxy has been used for the assessment of various intracerebral lesions, is presented. In 54 of these patients the cannula was introduced with a 20 MHz Doppler-probe positioned at the tip of the needle. A comparison of tissue specimens taken stereotactically with tissue material after tumour resection and/or autopsy was performed in 35 patients. The accuracy of the histological diagnosis was 88%. Bleeding as a complication due to the stereotactic intervention occurred in 8 patients (2.4%). Two of these patients had a fatal outcome (mortality: 0.6%). The morbidity (transient and permanent deterioration of the clinical status) was 1.2%. [ABSTRACT FROM AUTHOR]

A stereotactic convergent beam irradiation technique using a linear accelerator has been developed in order to precisely apply single high doses of up to 50 gray and more to brain lesions (radiosurgery). Accurate positioning of the patient and the target point of irradiation is an absolute requirement for this method. The stereotactic localization system developed for this purpose is described. [ABSTRACT FROM AUTHOR]

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Aim: Three-dimensional inverse treatment planning with modulated beams was applied for dosimetric optimization of a lengthy (22 cm) and complex (concave-convex) shaped planning target volume (PTV) in the cervical and upper mediastinal regions.Material and Method: The planning was done for 9 coplanar beams spaced evenly at 40 intervals. Properties of 15 MV photons from a linear accelerator were simulated. The optimization of the fluence modulation profiles for each beam was based on a definition of the desired/permitted relative dose levels in the PTV and organs at risk, and a definition of the strengths of the constraints to achieve these objectives.Results: An adequate dose delivery to the PTV and protection of the spinal cord are completely achievable. The dose delivered to the lungs is clinically acceptable with respect to the risk of radiation-induced pneumonitis. For reasons of physics, no further decrease in the radiation burden on the lungs can be attained with X-rays without compromising the PTV coverage. The radiation burden on some critical part of normal tissues was effectively reduced by application of a dummy organ at risk.Conclusion: The inverse planning is an effective method for conformal radiotherapy of large tumors as well. However, the power of the technique is insufficient when the tolerance dose of the neighbouring normal tissue is too low and its volume effect is high. Although requiring further operator interactions, introduction of dummy organs at risk may be of help in reducing the radiation burden on normal tissues. [ABSTRACT FROM AUTHOR]

This nonrandomized, controlled Phase II pilot study aims at the lowest effective dose of rectally applied sulindac to achieve and maintain adenoma reversion in colectomized patients with familial adenomatous polyposis (FAP).The study group (n = 15) underwent proctoscopic and laboratory follow-up for polyp reversion every 6 to 12 weeks. Polyp reversion was followed by dose reduction in predefined steps. Proliferating cell nuclear antigen/cyclin (PCNA) and KI-67 proliferation indices (PI) were performed by point counting. Prostaglandin (PG)E2 and PGF2α were quantified by time-resolved competitive fluorescence immunoassay.All patients responded to therapy within 6 to 24 weeks. Sixty and 87 percent of patients achieved complete adenoma reversion after 48 weeks at 53 and 67 mg of sulindac per day per patient on average, respectively. Reversion was evident compared with the control group. Dose reduction by one-sixth to one-eighth of the usual oral dose was significant (Mann's trend test, P < 0.05). PCNA and KI-67 Pls of adenomatous and flat mucosa were significantly reduced (Wilcoxon's test, P <0.05). Correlation of PCNA and KI-67 Pls indicate similar reaction of different tissue structures (Spearman's rank correlation test, P <0.01). Nonsteroidal anti-inflammatory drug-induced redifferentiation from high-grade to low-grade dysplasia occurred in all but two patients. Tissue-PGE2 levels were greatly reduced. Unwanted, curable side effects were rare (gastritis, n =2), and laboratory controls are within detection limits.Low-dose rectal sulindac maintenance therapy is highly effective in achieving complete adenoma reversion without relapse in 87 percent of patients after 33 months. Rectal FAP phenotype should be crucial for the surgical decision. Colectomy with ileorectal anastomosis and regular chemoprevention might proceed to be a promising alternative to pouch procedures. Chemoprevention with lower incidence of FAP-related tumors via dysplasia reversion may be possible in the future. [ABSTRACT FROM AUTHOR]

Copyright of Der Radiologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Der Radiologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Der Radiologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)