Biomedical subjects

P Wust

Publications and source records attributed to P Wust.

At least 73 records · Page 4Linked to original sources

PubMed1998

[Effectiveness of preoperative radio-chemo-thermotherapy with respect to thermometry in locally advanced rectal carcinoma].

Additional hyperthermia is able to intensify the effect of radio-chemotherapy in locally advanced rectal cancer. The datas represents favourable locally effect, if the necessary parameters of thermometry are achieved. We could demonstrate a correlation between temperatures and downstaging of the primary tumor. Consequently, aim of further developments is to optimize hyperthermia technology.

Combined Modality Therapy↗

PubMed1998

MRI-assisted specification/localization of target volumes. Aspects of quality control.

The transportation of MRI information on tumor extension into CT-based radiation therapy planning is desirable for several reasons. MRI's better contrast resolution is usually considered the most important, as it leads to a more exact definition of target volumes. Unlike diagnostic imaging, where a certain margin of error in depiction of tumor extension seems acceptable, radiation therapy planning makes it absolutely necessary, that the contents of every MR pixel (or voxel) correspond exactly to the corresponding area in the patient examined. This exact correspondence may be disturbed by a variety of influencing factors. Objects like various implants may lead to the most severe image distortions and--even worse--contrast alterations, some of which are not easily visible on the slices which are used for target volume definition. Additionally, MR images may have intrinsic faults which are able to change the correspondence between the voxel and the part of the patient's body it represents. Quality control has therefore to ensure that parameters like slice thickness are correct and kept constant by the imager. Image fusion may then be used to transfer MR information on tumor extension into the CT data. Electron density distribution provided by CT then allows for treatment planning. Implanted markers may then be used to ensure exact correspondence between the examined parts of the patient's body and the representing pixel or voxel. Care should be taken that landmarks themselves do not influence this relationship.

Brain Neoplasms↗

PubMed1997

[Thermometry by measuring the chemical shift of lanthanide complex].

BACKGROUND: In the long-term, non-invasive thermometry is vital for the continued clinical and technological development of regional hyperthermia. In magnetic resonance tomography. T1 relaxation time, diffusion and proton resonance frequency are used to measure temperature distributions. When used clinically in the pelvic region, all of these methods are plagued with errors and artefacts on account of the tissue relationships, tissue changes under hyperthermia, physiological and stochastic movements, inhomogeneities, drift phenomena and instabilities. MATERIAL AND METHOD: We tested the relationship between the temperature and the chemical shift of a methyl group of a lanthanide complex with central atom praseodymium (Pr-MOE-DO3A. Schering AG). To do this we used cylindrical phantoms containing a 5-mmol-solution of this temperature-sensitive substance. High resolution spectra and relaxation times were determined in a Bruker AMX at 11.5 T. A calibration curve was then recorded by a Siemens Magnetom SP63 at 1.5 T. Local temperature distributions were determined using the chemical shift imaging method, with a matrix size of 16 x 8 and a narrow-band excitation pulse. The temperature distribution was created using a Nd:YAG laser applicator. RESULTS: At a distance of -25.7 ppm from the water line, we found a singlet line with a temperature-dependent chemical shift of 0.13 ppm/C. In the phantom experiment we found that the chemical shift had a linear relationship with a gradient independent of the surroundings, and a temperature resolution of +/-0.6 degree C. With a concentration of 1 mmol/l, a matrix size of 8 x 8 and a measurement period of 5 s per acquisition, phantom measurements using the CSI method produced a signal to noise ratio of 3.5 per acquisition, i.e a measurement period of 10 to 20 s per spectrum. CONCLUSIONS: Our in vitro data show that spectroscopic temperature measurement using a temperature-sensitive praseodymium complex with a therapeutically practical concentration of 1 mmol/l already appears to be suitable for clinical use Compared with the methods tested so far (T1, diffusion, proton resonance), this method has the special advantage of not being very susceptible to artefacts. The competing methods of non-invasive thermometry using magnetic resonance tomography/spectroscopy will be investigated next.

Artifacts↗

PubMed1997

[A phase-I/II study on the local hyperthermia of cervical N2/N3 lymph node metastases].

BACKGROUND: Patients with advanced lymph node metastases from head and neck tumors at stage N2/N3 (i.e. UICC IV) present a difficult therapeutic problem. Despite combined radio-chemotherapy and hyperfractionated and/or accelerated fractionation regimens, local control of these tumors remains unsatisfactory. For this reason, the value of local radio wave/microwave hyperthermia was examined for this patient group in a phase I/II study.

Adult↗

PubMed1997

[Magnetic resonance tomography and endosonography in the preoperative staging of advanced rectal carcinomas after hyperthermoradiochemotherapy].

PURPOSE: Comparison of diagnostic accuracy of staging of endorectal sonography (ES) and body coil MRI after preoperative hyperthermoradiochemotherapy in patients with advanced rectal cancer. METHODS: Prospective analysis of MRI and ES in 30 patients after hyperthermoradiochemotherapy and correlation with histopathological patterns. RESULTS: T-staging by MRI was correct in 47% and by ES in 53% of the cases. Despite similar accuracy of staging in T0- and T1-tumours, we found different accuracies concerning T2-tumour staging about 63% versus 73% (MRI/ES), concerning perirectal infiltration 70% for both techniques, concerning invasion of adjacent organs 90% versus 87%, and concerning lymph node metastases without respect to the N-stage 63% versus 63%. CONCLUSION: Both imaging modalities provide useful information for operation planning despite limited accuracy after hyperthermoradiochemotherapy. The body coil MRI does not seem to be severely inferior to ES in post-therapeutic staging, despite better contour line imaging by ES. With respect to the determination of invasion of other organs, MRI seems to be more useful.

Adult↗

PubMed1997

[Fractal surface analysis of intrapulmonary space-occupying lesions from high-resolution CT studies].

PURPOSE: The visual assessment of shape and surface structures of pulmonary nodules (PN) (smooth edges vs. spiculae) serves as a qualitative, subjective criterion in differential diagnosis. These properties must be quantified by computer-assisted evaluation, an adequate mathematical model, and new quantitative shape parameters. METHODS: 12 patients were investigated by high resolution CT. Based on 3D reconstructions with increasing thresholds, the PN surface S, volume V, fractal dimension (FD = In(S)/ In(square root of V)), and fractal index (F1 = square root of S/ square root of V) were calculated. RESULTS: The relations between the reconstruction threshold and the calculated tumour surface, respective volume, are of a fractal nature: S = c1 x thres1/d, V = c2 x thres1/D (c1, c2, d, D: real constants). Whereas the absolute values of surface and volume strongly depend on the chosen threshold (mean volume differences of 249%), the derived parameter of the fractal dimension for a specific PN is nearly constant for all thresholds under review (r = 0.998, SD = 0.05). CONCLUSIONS: FD and FI are new diagnostic features for the assessment of PN surface structure and morphology. Thus, the assessment of pulmonary nodules can be supported by new quantitative parameters representing surface irregularity due to invasive tumour growth into adjacent tissue.

Aged↗

PubMed1997

[In vitro evaluation of MR thermometry in the implementation of laser-induced thermotherapy].

PURPOSE: To optimize the MR sequences parameter for monitoring hyperthermic effects in the tissue during laser induced thermotherapy (LITT). MATERIAL AND METHODS: Experimental studies were performed for the evaluation of MR-thermometry using a contrast-agent-water solution and a pig-liver. A T1-weighted TurboFLASH sequence and a FLASH-2D sequence were used. The TurboFLASH sequence was used with various T1 settings (between 100 and 1250 ms). MR findings were correlated with temperature measurements using a fluoride optical temperature measuring system in a distance of 1, 2, and 5 cm from the laser applicator. RESULTS: Using the contrast-agent-water solution demonstrated the temperature sensitivity of both sequences. In vitro evaluations using pig liver demonstrated a near linear increase of signal versus increasing tissue temperatures in a distance of 1 cm to the tip of the laser applicator. Optimal visualization of the temperature effects was obtained using a T1 between 100 ms and 400 ms. Using the FLASH-2D sequence a signal loss was documented at a TR of 110 ms. CONCLUSION: MR-thermometry using sequentially TurboFLASH and FLASH-2D sequences allowed a non-invasive monitoring of the laser induced temperature changes.

Animals↗

PubMed1997

Accuracy of staging rectal tumors with contrast-enhanced transrectal MR imaging.

OBJECTIVE: Our objective was to evaluate the accuracy of contrast-enhanced transrectal MR imaging in staging rectal adenoma and carcinoma by correlating with histopathologic findings. SUBJECTS AND METHODS: Thirty-five patients underwent transrectal MR imaging on a 1.5-T superconducting unit using unenhanced T1-weighted and T2-weighted spin-echo and turbo spin-echo sequences, a dynamic gadopentetate dimeglumine-enhanced turbo fast low-angle shot sequence, and enhanced T1-weighted spin-echo sequences. For all patients, histopathologic correlation was available from biopsy (n = 15) or surgical resection (n = 20). Two radiologists unaware of each other's interpretations of the scans interpreted each case from which we evaluated qualitative and quantitative data. RESULTS: Rectal adenomas (n = 15) were identified when imaging revealed an intact muscularis mucosae, a homogeneous internal structure, and high contrast enhancement of the lesion. Carcinomas staged as T1 by TNM criteria (n = 6) were best revealed by dynamic turbo fast low-angle shot sequences, in which an intact muscularis propria could be seen. Visualization of enhancing tumor tissue in the muscularis propria indicated T2 carcinoma (n = 5). All T3 (n = 5) and T4 (n = 4) carcinomas were correctly staged with dynamic and static MR imaging. The stage revealed by MR imaging correlated well with histologic staging results in 89% (observer 1) and 86% (observer 2) of interpretations. However, when interpreting MR imaging, observers tended to overstage and never understaged. CONCLUSION: Transrectal surface-coil MR imaging provided reliable information in staging patients before surgery and in evaluating rectal adenoma and carcinoma.

Adenoma, Villous↗

PubMed1996

Local hyperthermia of N2/N3 cervical lymph node metastases: correlationof technical/thermal parameters and response.

PURPOSE: Patients with advanced head and neck carcinomas, primarily nonresectable as well as recurrent cases, were treated in multimodality regimens with radiotherapy, chemotherapy, and local hyperthermia. Commercially available microwave and radiowave applicators were used in 50 patients with N2/N3 cervical lymph node metastases during more than 250 heat treatments. To assess technical suitability, the achieved power densities and thermal parameters were tested for correlation with anatomical and geometrical factors. To assess effectiveness, the response was compared with derived parameters of the achieved temperature distributions. METHODS AND MATERIALS: The temperature measurement points (in thermometry catheters) documented by computerized tomography are labeled according to tissue depth, shielding by osseous structures, and location in relation to the external applicators. Relative and absolute specific absorption rates (SAR) and cooling coefficients are extracted from the temperature-time curves. Time-averaged temperature-position curves are evaluated to obtain index temperatures (T90, T50, T20), minimum/maximum tumor temperatures, cumulative minutes T90 > or = 43 degrees C, and 43 degrees C-equivalent min T90. Radiation dose, treatment time, and chemotherapy regiment are also considered. A response parameter is defined using the pre- and posttherapeutic tumor volumes. A multivariate variance analysis is performed for the dependent variables power density, thermal parameters, and response. RESULTS: A significant correlation exists between power density and absorption, presence of a fat layer, and applicator illumination. The maximum depth is 5 cm, where SAR of >= 10 mW/g are registered. Achieved temperatures at individual measurement points are dependent on the SAR, and to a lesser extent, the perfusion-dependent cooling coefficients, but the index temperature T90 is only significantly related to intratumorally achieved SAR. The thermal gradient (T20-T50) and temperature peak (T20) are significantly influenced by the tumor volume. The response is directly related to the index temperature T90, equivalent minute T90 43 degrees C, and cumulative minutes T90 > or = 40.5 degrees C, and inversely related to the tumor volume. CONCLUSIONS: Local hyperthermia using microwave and radiowave applicators in the head and neck region is a tolerable and clinically practical supplementary therapy used as part of multimodal regimens, and has already been proven to be effective. However, the analyses also demonstrated the limits of currently available technology, and confirm the need for continued methodical research.

Adult↗

PubMed1996

Hyperthermia in the multimodal therapy of advanced rectal carcinomas.

The synergistic effects of hyperthermia (raising temperatures to 40 degrees C and above) when combined with radiotherapy and cytotoxic drugs and a modulation of immunological phenomena have been demonstrated in the laboratory. Pre-clinical data relating to hyperthermia are summed up, along with their implications for clinical application. Controlled studies of local and regional hyperthermia have been performed during recent years, and these show us that the adjunction of hyperthermia provides at least an improvement of local control compared with radiotherapy alone. Current clinical results are summarized. Therapy systems based on radiowave irradiation have been commercially available for regional hyperthermia of the pelvis since the mid 1980s. This technology allows us to perform sufficiently tolerable and effective regional hyperthermia on rectal carcinomas. Used as part of curative preoperative and postoperative multimodal therapeutic strategies, hyperthermia can lead to improvement in local control (resectability, down-staging, progression-free time, recurrence rate), at least for certain risk groups. The preoperative radio-chemo-thermotherapy of advanced primary and recurring rectal carcinoma, uT3/4, was tested in a phase-I/II study of 20 patients. Therapy procedure, acute toxicity, thermal parameters, and response are described and discussed for this patient group. The regimen proved to be sufficiently tolerable, and complications did not occur. Tumor resection was performed on 14 of the 20 patients; 13 of the procedures were R0-resections and one was an R2 resection. In 64% of the resected rectal carcinomas, histopathological down-staging of the pretherapeutic endosonographical stadium was achieved; in three of the patients, despite continued non-resectability, local control has now been maintained for more than 12 months. In two patients with nonresectable rectal carcinomas, local progress was seen during the neoadjuvant combination therapy.

Clinical Trials as Topic↗

PubMed1996

[3-D visualization of thoracic tumors from MR images].

AIM: In cooperation with the thoracic surgery department 3-D visualizations of tumors were generated to support the surgeons in preoperative planning. As opposed to 3-D reconstructions of CT data, those representations based on MRI images remain an exception. In this paper different methods of three dimensional visualization of lung tumors are presented and compared to each other. DESIGN: These methods are 1. contour based surface models, 2. threshold based surface models and 3. rendered scenes of segmented volume data with transparent, color-coded display. RESULTS: Combinations of all three methods in one single image are possible as well with the software we developed. Furthermore, cut planes through the original data can be integrated into the 3-D scene. The segmentation of anatomical objects is performed either manually or automatically with various procedures. CONCLUSIONS: Adequate possibilities of manipulation and archiving allow a fast handling and processing even of large data sets. The calculated volumes of the anatomical objects can be used for quantitative studies. Arbitrary views of the three dimensional reconstructions can be generated within a few seconds. Even animation can easily be calculated and displayed with 30 frames/second.

Adult↗

PubMed1996

[High-resolution magnetic resonance tomography by means of an endorectal coil--the results in rectal tumors].

PURPOSE: To assess the value of high-resolution MRI of the rectum using an endorectal coil. METHODS: 10 volunteers and in 31 patients with suspected rectal tumors were examined. In 17 patients (n = 17) with rectal carcinoma, of which 15 subsequently underwent radical surgery, the preoperatively obtained tumor stage was compared with histology. In 12 patients (n = 12) with rectal adenoma (severe and medium graded epithelial dysplasias according to the WHO) who underwent endoscopy the results of the endorectal surface coil examination were compared with endoscopy and histology. In 4 patients (n = 4) with large rectal adenomas the surface coil was used before and as follow-up after endoscopic electro laser resection and the absence of adenoma after therapy also in the deeper layers of the rectal wall could be confirmed. RESULTS: Visualization of anatomical structures of rectum and adjacent structures is improved by the use of the endorectal surface coil. The diagnosis of carcinoma and adenoma of the rectum and the documentation of the exact extension can be reached with high accuracy (85%). CONCLUSION: MRI with an endorectal surface coil may play an important role in the preoperative diagnosis of rectal carcinoma. This method is useful for primary diagnosis and follow-up of large rectal adenoma after endoscopic electro laser resection.

Adenoma↗

PubMed1996

[Radiation exposure in interventional radiology as exemplified by the chemoembolization of hepatocellular carcinoma and laser angioplasty of the pelvic arteries].

PURPOSE: Estimation of radiogenic risks for patient and radiologist in chemoembolisation of hepatocellular carcinoma (HCC) and laser angioplasty of the pelvic arteries. METHODS: In 5 chemoembolisations of HCC (4 males, one female) and 6 laser angioplasties of the pelvic arteries (5 males, one female) the surface doses received by patient and operator were measured using thermoluminescent dosimeters in standardised positions. The organ doses of the patient were derived by conversion factors employed on the measured surface doses. Effective dose was determined according to the recommendations of ICRP 60. RESULTS: The risk of lethal malignant disease and genetic disorder derived from the doses in the patient was found to be of the magnitude of 10(-4)-10(-5). The thresholds for transient erythema of the skin and depression of hematopoiesis can be reached after high expositions. A theoretical maximum of 700 laser angioplasties of the pelvic arteries allowable in one year was calculated based on the dose to the operator's left hand. For chemoembolisation of HCC, the dose to the left eye lens would reach the yearly maximum after approximately 1000 procedures. Remarkable risks for malignant disease of skin and thyroid as well as detectable opacities of the eye lens can occur after frequent interventions for many years. CONCLUSIONS: Because of the lower life expectancy the patient's risk for stochastic effect can be seen as minimal. No clinically relevant deterministic effects will occur. In the case of frequent interventions, the dose absorbed by the radiologist is likely to exceed the prescribed dose limit and to cause remarkable risk for stochastic and non-stochastic effects after many years.

Aged↗

PubMed1996

[An interstitial miniature antenna for localized in vivo P-31 MR spectroscopy].

BACKGROUND: Phosphorus spectroscopy can be used to assess response in tumor therapy and to monitor response. An additional response parameter would be useful for individualization in oncological therapy. Methodical problems of localisation and contamination make it more difficult to interpret and reproduce the spectra. Interstitial and endoluminal spectroscopy antennas placed directly within or close to the tumor could provide help in this problem. MATERIAL AND METHOD: We developed an interstitial 31P MRS antenna together with a tuning network which can be used in thermometry catheters for hyperthermia within an internal lumen of 1.1 mm in diameter. A prototype of this type of miniature antenna suitable for use in Siemens MRI scanners at 1.5 T was described spectroscopically with regard to excitation profile, range and SNR. RESULTS: In terms of quality, the excitation profiles of the interstitial antennas in relation to orientation correspond to those of comparable but considerably larger endocavitary antennas and catheter coils for MR imaging and spectroscopy. Maximum sensitivity was achieved by aligning the coil normal perpendicular to the B0 field. Signal losses of up to 50% have to be reckoned with when using other orientations. The maximum range of the interstitial antenna was determined using spectroscopy and was found to be 5 mm, i.e. 9 times coil radius. The sensitivity (SNR, detection sensitivity) of the studied type of interstitial antenna allows in vivo 31P spectroscopy to be performed despite the unusually low axial dimension (coil radius r = 0.55 mm). The prototype of the described interstitial antenna was used to measure an in vivo spectrum from the back muscle of a rabbit in 10 min. Nevertheless, the detection volume of at least some ml necessary for 31P spectroscopy results mainly from the large antenna length. CONCLUSION: The sensitivity (SNR, detection sensitivity) of the interstitial antenna needs to be further improved in order to assess treatment response in patients. However, the construction principle is suitable for intracavitary 31P spectroscopy antenna with larger diameters, which can be used for advanced rectal, cervical and prostate carcinomas.

Animals↗

PubMed1996

[Computer graphics methods for 3-dimensional imaging of intrapulmonary space-occupying lesions of CT and MRI images].

AIM: To improve the pre-operative planning of interventional procedures in thorax surgery different methods of computer-graphical visualization of intrapulmonary lesions and adjacent anatomical structures based on CT and MR data were realized and compared to each other. DESIGN: In 21 patients with intrapulmonary lesions the image data was segmented by interactive and automatic algorithms and different reconstruction techniques were applied (maximum intensity projection; color-encoded and transparent surfaces; volume rendering). Based on these three-dimensional reconstructions, different views from arbitrary perspectives (including simulated endoscopic images) were generated and animated film sequences of the 3D scene were displayed with 30 frames/second. RESULTS: For all patients under review, a high-quality presentation of the relevant structures was obtained by use of the applied computer-graphical techniques. Even combinations of different visualization methods in one image can be generated with the software we developed. CONCLUSIONS: The various methods for image segmentation allow a fast and comfortable processing even of large data sets. The calculated values of tumor surface and volume can be used for quantitative studies and therapy control. The planning of surgical and interventional procedures can be supported by the simultaneous visualization of the intrathoracic lesion and the surrounding structures.

Aged↗

PubMed1995

[MR-guided laser-induced thermotherapy in tumors of the head and neck region: initial clinical results].

PURPOSE: To analyse the value of MR-guided laser-induced thermotherapy (LITT) for palliative treatment of recurrent tumours of the head and neck region. MATERIAL AND METHODS: 8 patients with recurrent tumours of the head and neck region (squamous cell carcinomas n = 6, pleomorphic adenomas n = 2) underwent MR-controlled LITT. A 7 French laser applicator was inserted under local anaesthesia into the centre of the recurrent tumour. A Nd:YAG laser with a wavelength of 1064 nm was used. Therapy was monitored on-line using special MR thermosequences. RESULTS: Preinterventional contrast-enhanced MRI revealed a recurrent tumour of the head and neck region for all eight patients. All patients tolerated the procedures well under local anaesthesia, with no clinically relevant side effects. The MR thermosequences depicted up to 15 mm diameter areas of less signal near the laser tip. Postinterventional contrast-enhanced MRI revealed hypovascularized areas due to the resulting coagulative necrosis. Coagulative necrosis of 4 cc to 28 cc occurred in all patients, and a reduction of clinical symptoms was achieved in five. CONCLUSION: The results obtained indicate that minimal invasive LITT can be a therapeutic alternative for palliative treatment of head and neck tumours.

Adenoma, Pleomorphic↗

PubMed1995

Recurrent nasopharyngeal tumors: preliminary clinical results with interventional MR imaging--controlled laser-induced thermotherapy.

PURPOSE: To evaluate magnetic resonance (MR) imaging-controlled laser-induced thermotherapy (LITT) in the treatment of recurrent head and neck tumors. MATERIALS AND METHODS: Six patients with recurrent nasopharyngeal tumors (squamous cell carcinoma [n = 4], pleomorphic adenoma [n = 2]) underwent LITT with local anesthesia. A 7-F introducing sheath was inserted into the center of the tumor followed by a specially designed laser emitter. Therapy was monitored on-line with MR thermometry, and the amount of necrosis was estimated with dynamic and static contrast material-enhanced sequences. RESULTS: All procedures were well tolerated with use of local anesthesia, with no clinically relevant side effects. MR thermometry depicted up to 15-mm-diameter areas of less signal intensity near the laser tip. Coagulative necrosis was achieved in all patients (volume range, 4-28 cm3), and clinical symptoms were reduced in four. CONCLUSION: MR imaging-controlled LITT may be a safe, minimally invasive alternative in the treatment of recurrent head and neck tumors.

Adenoma, Pleomorphic↗

PubMed1995

[The use of an early postoperative interstitial-hyperthermia combination therapy in malignant gliomas].

BACKGROUND: The survival of people suffering from malignant gliomas (WHO level III and IV) is predominantly limited by local progress in the primary tumor region. Interstitial hyperthermia combined with radiotherapy or chemotherapy is one approach for the intensification of local therapy. It is possible to combine (partial) tumor resection with hyperthermia as well as with brachytherapy by implanting catheters intraoperatively. PATIENTS AND METHODS: A pilot study was performed to examine practicality, tolerability, effectiveness and scope for improvement in early postoperative hyperthermia treatment following catheter implantation as part of (partial) tumor resection. Each CT data set was transferred into a VAX 3100 workstation for retrospective analysis of the hyperthermia treatment. The implanted catheters were segmented and the distributions of power density and temperature were simulated. We sought to achieve the best possible temperature distributions by optimising the catheter arrangement in the planning calculations. The corresponding Ir-192-source brachytherapy treatments were simulated in a similar way using the implanted, as well as optimised catheter arrays. RESULTS: Intraoperative catheter implantation in 4 patients was problem-free. Postoperative complications were not observed, neither were infections. Interstitial microwave hyperthermia in combination with percutaneous irradiation or chemotherapy a few days after the operation was also tolerated well by all patients. Effective temperatures (of at least 42 degrees C) were regularly achieved at measurement points, but the temperature distributions were unsatisfactory, with T90 values (the temperature reached in at least 90% of the target volume) of under 38 degrees C. Measured temperature/position curves showed qualitative correlation with the simulated calculations. The catheter positions determined by optimisation varied significantly from the positions clinically used. CONCLUSIONS: Early postoperative combination therapy using hyperthermia for the treatment of malignant gliomas is a very practical approach. The optimisation strategies described should be used preoperatively to plan catheter arrays for interstitial hyperthermia and brachytherapy, and these arrays should be implanted using stereotaxic surgery.

Antineoplastic Agents↗