Randomized trial with early-stage Hodgkin's disease testing 30 Gy vs. 40 Gy extended field radiotherapy alone.

Purpose: To evaluate whether or not a total dose (TD) of 30 Gy is sufficient for treatment of assumed subclinical Hodgkin's Disease compared to 40 Gy TD with early stage Hodgkin's Disease (ESHD).

Methods And Materials: In a prospective multicenter trial, 376 patients with laparotomy-proven ESHD stages PS IA to PS IIB without risk factors such as large mediastinum, massive splenic involvement, extranodal disease, elevated erythrocyte sedimentation rate (ESR), and/or three or more involved lymph node areas were randomly allocated either to receive (ARM A) 40 Gy TD extended field-radiotherapy (EF-RT) or (ARM B) 30 Gy TD EF-RT plus 10 Gy TD involved field-radiotherapy (IF-RT), both arms without any chemotherapy. Three hundred sixty-six of these patients were evaluable for early and long-term response, such as remission status, freedom from treatment failure (FFTF), and overall survival (OAS).

An automated fast MR-imaging method for localized measurements of dose distributions using NMR-Fricke gel dosimetry. Evaluation of influences on the measurement accuracy.

Purpose: The calculation of radiation absorbed dose using a chemical dosimeter and NMR-imaging techniques provides non-invasive 3D dosimetry. The main problems with this new method are measurement accuracy and diffusion effects. These involve influences on chemical preparations, correct data acquisition (evaluation of the T1 values) and a lack of methods for reducing diffusion effects.

Use of surface markers for MR radiotherapy planning.

Purpose: For the precise planning of radiotherapy treatment ports, the delineation and control of their borders has to be performed with X-ray and other imaging procedures before and during the therapy.

Materials And Methods: Conventional planned therapy ports are checked with the help of MR-imaging with new gel-markers, as a further development to formerly used fluid filled tubes, on the skin of the patient in different regions. We describe the essentials of these gels and report about their first practical use.

[A comparative consideration of para-aortic fields within the framework of the German Hodgkin's Disease Study].

In 33 patients of the multicenter German Hodgkin's Lymphoma Study Group the field borders of the paraaortic field were compared computer-assisted. It was seen that fields are chosen often too small or too large, though precise description of the fields is given in the protocol. In these patients the para-aortics were irradiated exclusively as extended field region.

[The initial clinical experiences with a dynamic FLASH-2D sequence in tumors of the head and neck area].

28 patients with clinically confirmed head and neck tumours were examined by MRI. The results of a dynamic FLASH-2D sequence and a Gd-DTPA enhanced T1-weighted sequence were analysed and retrospectively compared with surgery and pathological findings. The extent of tumours was clearly defined by the dynamic technique in 21 cases.

Radiation therapy verification in brachytherapy combining iron sulphate gel irradiation and magnetic resonance imaging (MRI).

We developed a verification method that allows the three-dimensional qualitative delineation of the dose inside an applicator during intracavitary brachytherapy using MRI of dose-dependent changes of iron sulphate. In addition to computer calculations, the verification of the dose distribution is depicted now within the applicator. Therefore one can get a qualitative information about the relative position of the applicator according to the tumor volume and the desired brachytherapy radiation volume.

[Diabetes insipidus and breast carcinoma--the importance of NMR tomography (MRT) in therapy planning].

In patients with advanced breast cancer the incidence of diabetes insipidus is between 0.1% and 0.9%.

[Case reports on the importance of the locoregional radiotherapy of Merkel cell tumor].

The Merkel cell tumor is becoming an increasingly diagnosed primary neoplasm of the skin. This subepidermal tumor is commonly located on the head and neck or extremities of elderly patients. Occasionally misinterpreted as cutaneous metastases, they show a high rate of local recurrence (27 to 52%) and distant metastatic spread (18 to 52%).

A skin MR-marker for radiation treatment planning.

After experiences with fluid filled tubes a gel fitted with an adhesive has been developed, to reproducibly markate treatment ports on the patient's skin. A gel is chosen, that hinders loss of the fluid and smoothly fits to the skin surface due to the adhesive. The clinical use of the gel hopefully will help with the use of NMR image information in radiotherapy treatment planning.

Fast inversion recovery T1 contrast and chemical shift contrast in high-resolution snapshot FLASH MR images.

Fast MR imaging attracts the interest of both clinicians and physicists because new diagnostic information arises with reduced artifacts due to short investigational times. With the acceleration of the Snapshot FLASH MR sequence, the measurement of high-resolution images with 256 x 256 matrix is reported, together with contrasting prepulses that are applied to attain contrast in combination with higher in-plane resolution. Measuring times are in the range of a second.

[The intracavity radiotherapy of cervical carcinoma with flexible applicators following the vesicovaginal interposition of the uterus].

Advantages of new flexible intracervical applicators treating cervical cancer with high dose rate afterloading brachytherapy are reported: The insertion of the flexible applicator is usually possible without anesthesia and dilation of the cervix. Therefore the treatment can be performed on an outpatient basis. The risks of perforation and infection are minimal.

[Diagnosis of oropharyngeal function with FLASH-MR tomography].

Magnetic resonance imaging (MRI) has several advantages over conventional X-ray methods: the patient is not exposed to radiation; images of any chosen level can be taken without changing the position of the patient; soft tissues are well differentiated; and artefacts due to dental materials are avoided. Thus, in certain fields of ENT diagnosis MRI is superior to computed tomography, for example, in the imaging of acoustic neuromas, glomus tumours and tumours of the parotids, oropharynx and orbit. The measuring time per slice image, which was previously measured in minutes, has been reduced by a factor up to 1000 by the FLASH (fast low angle shot) technique.

Cardiac and vascular imaging with an MR snapshot technique.

Real-time vascular and cardiac magnetic resonance (MR) imaging has been reported only with echo-planar imaging. In this study, the fast low-angle shot (FLASH) MR imaging sequence was reduced to repetition times of 3 msec and echo times of less than 1.3 msec with use of an improved MR imaging system.

3D-snapshot flash NMR imaging of the human heart.

SNAPSHOT-FLASH is a recently developed, ultrafast imaging technique, based on conventional FLASH imaging. The application of this new variant to 3D imaging allows the acquisition of a 128 x 128 x 32 data set in 12.5 seconds without triggering, or for cardiac imaging with gating within 32 heartbeats.

Inversion recovery snapshot FLASH MR imaging.

Snapshot fast low angle shot (FLASH) magnetic resonance (MR) imaging techniques have been developed to enable real time imaging of MR parameters. The method is based on a 64 x 128 FLASH tomogram acquired within less than 200 ms. This work describes snapshot FLASH MR using a single 180 degrees pulse prior to the acquisition of a series of FLASH images.

SYS-FLASH. Systemic saturation in FLASH MR imaging.

A simple modification of FLASH (Fast Low Angle SHot) MR imaging, which results in a variable reduction of the intensity of flowing blood and flow artifacts in transaxial tomograms, is reported. Here a nonselective radiofrequency pulse of variable flip angle is used before the acquisition of each projection in FLASH imaging to saturate flowing blood within the whole volume (SYstemic Saturation = SYS-FLASH).

ECG-triggered arterial FLASH-MR flow measurement using an external standard.

In ECG-triggered FLASH-MR images, the inflow of unsaturated spins into the imaging plane results in the reproducible delineation of time variant flow in the arterial system. With the additional acquisition of an external reference image upstream the arterial vessel under investigation, the quantification of flow is possible with the FLASH-MR sequence in one measurement. The method allows the rapid measurement of arterial flow at least in great vessels.

Biophysica and medical aspects of fast NMR-imaging.

Nuclear magnetic resonance (NMR) imaging is a promising new technique for non-invasive medical diagnosis. Following a decade of technical improvements and preliminary medical experiences, the measuring time of several minutes remained the major drawback of the method. The recent development of a fast NMR-imaging technique, the so-called FLASH (Fast Low Angle SHot) method, opens a new field of medical applications.

Multiple chemical shift selective (CHESS) MR imaging using stimulated echoes.

Recently, stimulated echo acquisition mode (STEAM) magnetic resonance (MR) imaging has been demonstrated as a new tool for multiparametric MR imaging studies. Applications of the chemical shift selective (CHESS) STEAM technique using a 2.0-T whole-body MR imaging system are reported in which a series of contiguous cross-sectional images of the head and the pelvis were acquired.

MR imaging using stimulated echoes (STEAM).

The introduction of STEAM (stimulated echo acquisition mode) magnetic resonance (MR) sequences provides access to a variety of MR parameters. T1-weighted and calculated T1 proton MR images of the head of healthy volunteers and a patient with an astrocytoma are presented. MR examinations were performed with a 2.

Multipurpose NMR imaging using stimulated echoes.

STEAM (stimulated-echo acquisition mode) imaging techniques recently introduced by the authors are demonstrated to provide a versatile tool for improving the parametric specificity in NMR imaging. Stimulated echoes can be excited by a sequence of at least three rf pulses with flip angles of 90 degrees or less. The main characteristics of the STEAM method are based on the great functional flexibility of an imaging sequence comprising three rf pulses unequal to 180 degrees and three intervals prior to acquisition of the data.