[First experiences with computer-assisted frameless stereotactic interstitial brachytherapy (CASIB)]. / Erste Erfahrungen mit computerunterstützter stereotaktischer interstitieller Brachytherapie.

PURPOSE: To reach an optimal treatment result and to avoid damage to critical structures a homogeneous dose distribution in the tumor volume with a rapid decreasing dose to the surrounding structures is necessary. Fractionated interstitial brachytherapy of tumors in the ENT region employing needles depends on exact localization of the target volume during all fractions. Therefore reproducibility of positioning of the needle(s) plays an important role. MATERIAL AND METHODS: We used the ISG Viewing Wand system in combination with the Vogele-Bale-Hohner (VBH) head holder and a new targeting device. Point of entrance, pathway, and target point of the needle were planned and insertion of the needle simulated in advance. To date we have treated 7 patients with inoperable tumors in the ENT region. The actual position of the needle in the control CT was compared to the planned position. RESULTS: The accuracy of positioning of the needle depended on the location of the tumor. In a patient with a recurrent retroorbital adenocarcinoma the mean accuracy was 1 mm. Due to soft tissue displacement in the neck region and the resulting necessity to readjust the targeting device the needle was placed with a mean deviation of 15 mm between the planned and the actual position. CONCLUSIONS: Computer-assisted frameless stereotactic interstitial brachytherapy allows for precise, reproducible and preplanned insertion of hollow needles into target structures closely adherent to the surrounding tissue, thus avoiding damage of neighbouring structures. This technique is of great advantage in treating deeply seated tumors which are fixed to bony structures, especially at the skull base. Inaccuracy in the neck region caused by soft tissue shift requires improvement of the immobilization in this region.

[3D navigation for interstitial stereotaxic brachytherapy]. / 3D-Navigation in der interstitiellen stereotaktischen Brachytherapie.

AIM: The aim of this paper is to describe the adaption of 3D-navigation for interstitial brachytherapy. The new method leads to prospective and therefore improved planning of the therapy (position of the needle and dose distribution) and to the possibility of a virtual simulation (control if vessels or nerves are on the pathway of the needle). MATERIAL AND METHODS: The EasyGuide Neuro navigation system (Philips) was adapted in the way, that needles for interstitial brachytherapy were made connectable to the pointer and correctly displayed on the screen. To determine the positioning accuracy, several attempts were performed to hit defined targets on phantoms. Two methods were used: "free navigation", where the needle was under control of the navigation system, and the "guided navigation" where an aligned template was used additionally to lead the needle to the target. In addition a mask system was tested, whether it met the requirements of stable and reproducible positioning. The potential of applying this method in clinical practice was tested with an anatomical specimen. RESULTS: About 91% of all attempts lied within 5 mm. There were even better results on the more rigid table (94% < 4 mm). No difference could be seen between both application methods ("free navigation" and "navigation with template"), they showed the same accuracy. CONCLUSIONS: The accuracy of the phantom experiments and the confirmation by the experiment with the anatomical specimen showed that excellent results can be expected in clinical practice using rigid tables and patient supporting systems.

VBH head holder to improve frameless stereotactic brachytherapy of cranial tumors.

Precise target localization is essential for brachytherapy. We have adapted the VBH (Vogele-Bale-Hohner) head holder (Wellhoefer Dosimetry, Schwarzenbruck, Germany), originally developed at the University of Innsbruck, for frameless stereotactic surgery, for use in brachytherapy of cranial tumors. The VBH head holder allows for rigid, noninvasive head fixation by means of an individualized upper dental cast. Registration rods, rigidly attached to the dental cast, provide stable external points of reference. The dental cast is sucked against the upper palate by vacuum, and then the fixated patient is scanned. During simulation, the targeting device can be positioned with respect to the virtual patient using the ISG Viewing Wand. Following simulation, the real patient is repositioned under vacuum control, the targeting device repositioned as well, and the actual brachytherapy initiated. The VBH head holder is well tolerated by patients and simple to use, and various studies have confirmed submillimeter accuracy. The modified head holder in combination with a new targeting device allows for precise and well-planned insertion of hollow needles into a tumor using frameless stereotactic systems as well as being compatible for uses in other fields.

Increased radiosensitivity by a combination of 9-cis-retinoic acid and interferon-y in breast cancer cells.

Interferons (IFNs) and retinoic acid (RA) are known to possess antiproliferative effects in various human cancer cell lines, including squamous cervix carcinoma and breast cancer cell lines. Frequently synergistic effects could be observed by the combination of both, and in clinical trials high response rates could be achieved by IFN-alpha in combination with 13-cis-RA in patients with squamous carcinoma of the uterine cervix. Since radiation-potentiating effects of IFNs and RA were described, we evaluated the additional impact of irradiation on three human breast cancer cell lines and investigated the antiproliferative effects of single, double, or triple treatments with IFN-gamma, 9-cis-RA, and irradiation. Antiproliferative effects were observed in all cell lines by any single treatment. When combining IFN-gamma with 9-cis-RA, synergism could be observed in all experiments. The combination of either IFN-gamma or 9-cis-RA with irradiation resulted mostly in additive effects. Irradiation contributed additive or further synergistic effects to the already synergistic effects of the combination of these two drugs. Thus synergism of IFN-gamma and 9-cis-RA always at least persisted fully. These results suggest that a regimen of IFN, RA, and radiotherapy (RT) might be a promising combination in the therapy of solid tumors, where RT is part of the conventional treatment.

In-flight medical emergencies. One year of experience with the enhanced medical kit.

Recent regulations require commercial US aircraft to carry an enhanced medical kit. We reviewed kit use on United Airlines during the initial year of the regulations. We also surveyed passengers who became ill during flight and health care providers who used the new kit. The medical kit was used 362 times on 361 flights (once in every 1900 flights or one use for every 150,000 air travelers). Health care providers indicated that the kit was useful in more than 80% of emergencies and was occasionally lifesaving. In the emergencies in which the kit was used, 70% fell into one of seven major diagnostic groupings, including syncope/near syncope (29%), cardiac/chest pain (16%), asthma/lung disease/shortness of breath (10%), and allergic reactions (5%). With 450 million domestic air travelers per year, we would expect 3000 in-flight medical emergencies annually, and conclude that the enhanced medical kit is beneficial and propose that its effectiveness would be improved by the addition of a bronchodilator for inhalation.