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Peter Wust

Publications and source records attributed to Peter Wust.

At least 37 records · Page 2Linked to original sources
PubMed2005

Dose-escalated conformal radiotherapy of glioblastomas -- results of a retrospective comparison applying radiation doses of 60 and 70 Gy.

BACKGROUND: Dose escalated three-dimensional conformal radiotherapy with 70 Gy against glioblastomas was compared retrospectively with the standard scheme of 60 Gy using 2-D-planning. PATIENTS AND METHODS: In the period from 1994 to 1998, a series of 135 patients with glioblastomas was treated by surgery and postoperative radiotherapy. A conversion from 2-D into 3-D-planning was carried out in 4/1996. The prescribed total dose for the first 65 patients was 60 Gy (group 60). A boost up to 70 Gy was added for the remaining 70 patients (group 70). RESULTS: The median survival time was 8.0 months for group 60 and 8.3 months for group 70. A dependency on the applied dose range was found. The median survival time was 3 months for patients who received a radiation dose of 55 Gy or less, 8.6 months for doses between 56 and 65 Gy, and 9.6 months for patients with a dose between 66 and 75 Gy (p < 0.01). In a multivariate analysis only the performance status maintained significance (p = 0.02) as a prognostic factor, while the dose range reached borderline significance (p = 0.09). CONCLUSION: No statistically significant survival prolongation was reached despite a dose escalation to 70 Gy.

Brain Neoplasms↗
PubMed2005

Hyperfractionated accelerated chemoradiation with concurrent fluorouracil-mitomycin is more effective than dose-escalated hyperfractionated accelerated radiation therapy alone in locally advanced head and neck cancer: final results of the radiotherapy cooperative clinical trials group of the German Cancer Society 95-06 Prospective Randomized Trial.

PURPOSE: To report the results and corresponding acute and late reactions of a prospective, randomized, clinical study in locally advanced head and neck cancer comparing concurrent fluorouracil (FU) and mitomycin (MMC) chemotherapy and hyperfractionated accelerated radiation therapy (C-HART; 70.6 Gy) to hyperfractionated accelerated radiation therapy alone (HART; 77.6 Gy). PATIENTS AND METHODS: Three hundred eighty-four stage III (6%) and IV (94%) oropharyngeal (59.4%), hypopharyngeal (32.3%), and oral cavity (8.3%) cancer patients were randomly assigned to receive either 30 Gy (2 Gy every day) followed by 1.4 Gy bid to a total of 70.6 Gy concurrently with FU (600 mg/m(2), 120 hours continuous infusion) days 1 through 5 and MMC (10 mg/m(2)) on days 5 and 36 (C-HART) or 14 Gy (2 Gy every day) followed by 1.4 Gy bid to a total dose of 77.6 Gy (HART). The data were analyzed on an intent-to-treat basis. RESULTS: At 5 years, the locoregional control and overall survival rates were 49.9% and 28.6% for C-HART versus 37.4% and 23.7% for HART, respectively (P = .001 and P = .023, respectively). Progression-free and freedom from metastases rates were 29.3% and 51.9% for C-HART versus 26.6% and 54.7% for HART, respectively (P = .009 and P = .575, respectively). For C-HART, maximum acute reactions of mucositis, moist desquamation, and erythema were lower than with HART, whereas no differences in late reactions and overall rates of secondary neoplasms were observed. CONCLUSION: C-HART (70.6 Gy) is superior to dose-escalated HART (77.6 Gy) with comparable or less acute reactions and equivalent late reactions, indicating an improvement of the therapeutic ratio.

Actuarial Analysis↗
PubMed2005

Value of 123I-IMT SPECT for diagnosis of recurrent non-astrocytic intracranial tumours.

The value of single-photon emission tomography (SPECT) using iodine-123-alpha-methyl-tyrosine (IMT) for the diagnosis of recurrent or residual gliomas is well established. In the current study we investigated whether IMT-SPECT could also be useful in the follow-up of brain metastases and other intracranial tumours of non-astrocytic origin. The study included 22 patients with suspected recurrent intracranial tumours of non-astrocytic origin (12 brain metastases, one supratentorial primitive neuroendocrine tumour (PNET), one rhabdoid tumour, two clivus chordomas, three ependymomas, two pituitary tumours, one anaplastic meningioma) who had previously been treated by surgery and/or radio/chemotherapy. SPECT results were correlated with clinical and MRI follow-up data. The study was true positive in 13 patients, true negative in five, false positive in one and false negative in three patients. Notably, all false negative findings were <13 mm. The resulting sensitivity of the IMT-SPECT was 81%. We concluded that the IMT-SPECT is a promising complementary imaging tool for the detection of recurrences of non-astrocytic intracranial tumours and their distinguishing from treatment-induced changes. The limitation of the IMT-SPECT is its low sensitivity for the detection of small lesions.

Adolescent↗
PubMed2005

A practical approach to thermography in a hyperthermia/magnetic resonance hybrid system: validation in a heterogeneous phantom.

PURPOSE: This study investigates the feasibility and accuracy of noninvasive magnetic resonance (MR) monitoring for a system that includes a multiantenna applicator for part-body hyperthermia (SIGMA-Eye applicator, BSD-2000/3D) and a 1.5 Tesla MR tomograph (Siemens Magnetom Symphony). METHODS: A careful electrical decoupling enabled simultaneous operation of both systems, the hyperthermia system (100 MHz, up to 1600 W) and the MR tomograph (63.9 MHz). We used the phase data sets of a gradient echo sequence (long echo time TE = 20 ms) according to the proton frequency shift (PFS) method to determine MR temperature changes. Data postprocessing and visualization was conducted in the software platform AMIRA-HyperPlan. Heating was evaluated in an elliptical Lucite cylinder of 50 cm length filled with tissue-equivalent agarose and a skeleton made from low-dielectric material to simulate the heterogeneity of a real patient. Multiple catheters were included longitudinally for direct thermometry (using Bowman high-impedance thermistors). The phantom was positioned in the 24-antenna applicator SIGMA-Eye employing the integrated water bolus (filled with deionized water) both for coupling the radiated power into the lossy medium and to enable a correction procedure based on direct temperature measurements. RESULTS: In eight phantom experiments we monitored the heating in the applicator not only by repetitive acquisition of three-dimensional MR datasets, but also by measuring temperature-time curves directly at selected spatial positions. For the correction, we specified regions in the bolus. Direct bolus temperatures at fixed positions were taken to aim at best possible agreement between MR temperatures and these direct temperature-time curves. Then we compared additional direct temperature-position scans (thermal maps) for each experiment with the MR temperatures along these probes, which agreed satisfactorily (averaged accuracy of +/- 0.4-0.5 degrees C). The deviations decreased with decreasing observation time, temperature increase, and thermal load to the surroundings (corresponding to bolus heating)-estimating a resolution of, at best, +/- 0.2-0.3 degrees C. The acquired MR temperature distributions give also insight into limitations and control possibilities of regional hyperthermia (annular phased array technology) for various tumor sites. CONCLUSIONS: On-line MR monitoring of regional hyperthermia by using the PFS method is feasible in a phantom setup and can be further developed for clinical applications.

Feasibility Studies↗
PubMed2005

Regional hyperthermia in conjunction with definitive radiotherapy against recurrent or locally advanced prostate cancer T3 pN0 M0.

BACKGROUND AND PURPOSE: Since long-term results of the standard treatment of locally advanced or recurrent prostatic carcinoma are unsatisfactory, the role for additional regional hyperthermia was evaluated in a phase I/II study. PATIENTS AND METHODS: From 08/1996 to 03/2000, 22 patients were treated by a standard irradiation regimen (68.4 Gy) in combination with regional hyperthermia (weekly, five to six times), and five of 22 patients received short-term (neoadjuvant) hormonal treatment. Of these, 15 patients had primary prostatic carcinoma T3 pN0 M0 and seven a histologically confirmed local recurrence after radical prostatectomy. Feasibility of hyperthermia, and acute/late toxicity as well as long-term follow-up (prostate- specific antigen [PSA] control, overall survival) were analyzed. Clinical endpoints were correlated with thermal parameters. RESULTS: Mean maximum temperatures along the urethra of 41.4 degrees C (41.0 degrees C for the recurrences), and mean T(90) values of 40.7 degrees C could be achieved. Severe acute toxicity of grade 3 occurred at the rectum in three, at the urethra in four, at the intestine in one, and a burn induced by hyperthermia in one of 22 patients. Late toxicity was only observed rectally in one patient (grade 3) and at the urethra in two patients (grade 2). There was no correlation between thermal parameters and any toxicity. The survival curves showed a PSA control for primary prostatic carcinoma > 50% after 6 years, but no long-term PSA control for the recurrences. Overall survival after 6 years was 95% for primary carcinoma, and 60% for the recurrences. There was a clear correlation between higher temperatures or thermal doses with long-term PSA control. CONCLUSION: Regional hyperthermia might be a low-toxicity approach to increase PSA control of common treatment schedules. Further evaluation, in particular employing improved hyperthermia technology, is worthwhile.

Aged↗
PubMed2005

A clinical water-coated antenna applicator for MR-controlled deep-body hyperthermia: a comparison of calculated and measured 3-D temperature data sets.

A magnetic resonance (MR)-compatible three-dimensional (3-D) hyperthermia applicator was developed and evaluated in the magnetic resonance (MR) tomograph Siemens MAGNETOM Symphony 1.5 T. Radiating elements of this applicator are 12 so-called water coated antenna (WACOA) modules, which are designed as specially shaped and adjustable dipole structures in hermetically closed cassettes that are filled by deionized water. The WACOA modules are arranged in the applicator frame in two transversal antenna subarrays, six antennas per subarray. As a standard load for the applicator an inhomogeneous phantom was fabricated. Details of applicator's realization are presented and a 3-D comparison of calculated and measured temperature data sets is made. A fair agreement is achieved that demonstrates the numerically supported applicator's ability of phase-defined 3-D pattern steering. Further refinement of numerical models and measuring methods is necessary. The applicator's design and the E-field calculations were performed using the finite-difference time-domain (FDTD) method. The calculation and optimization of temperature patterns was obtained using the finite element method (FEM). For MR temperature measurements the proton resonance frequency (PRF) method was used.

Computer Simulation↗
PubMed2005

CT-guided interstitial single-fraction brachytherapy of lung tumors: phase I results of a novel technique.

PURPOSES: To assess the safety of CT-guided brachytherapy of lung malignancies and to evaluate the initial therapeutic response. PATIENTS AND METHODS: Fifteen patients with 30 lung malignancies were included in this prospective phase I trial (metastases, 28; non-small cell lung cancers, 2). Pre-interventionally two patients had a vital capacity of < 80% (39% and 63%). These two patients, and one other, had FEV1 values of < 80% predicted (17%, 48%, and 64%). Tumors with a maximum diameter of 4 cm were treated with a single brachytherapy catheter that was positioned under CT-fluoroscopy. In two tumors with tumor diameters of 5.5 and 6.5 cm, two applicators were used. In one patient with an 11-cm irregularly shaped tumor, nine catheters were inserted. Treatment planning for 192Ir brachytherapy was performed using three-dimensional CT data that were acquired after percutaneous applicator positioning. All procedures were performed under local anesthesia. A follow-up CT was performed 6 weeks later and every 3 months pos-tintervention. RESULTS: The mean diameter of the 30 lung tumors was 2 cm (range, 0.6 to 11 cm; median diameter, 1.5 cm). The minimal dose within the tumor margin was 20 Gy in all 30 tumors treated. Except for nausea in one patient and focal hemorrhage detected on CT in two patients, no acute adverse events were recorded. One patient developed an abscess at the previous tumor location 9 months after treatment, which proved to be a local tumor recurrence. The median follow-up period was 5+ months with a local tumor control of 97%. CONCLUSION: The novel technique of CT-guided interstitial brachytherapy was safe for the treatment of lung tumors and yielded a very low complication rate. The initial data on therapeutic response are promising.

Adult↗
PubMed2005

Goal-directed therapy of cardiac preload in induced whole-body hyperthermia.

OBJECTIVES: To optimize volume therapy during induced whole-body hyperthermia (WBH) < or = 42.2 degrees C, pulmonary capillary wedge pressure (PCWP) and intrathoracic blood volume index (ITBVI) were compared as goal parameters. DESIGN: Prospective clinical study. SETTING: ICU at university hospital. PATIENTS: Twenty-three patients with metastatic cancers. INTERVENTIONS: Radiant WBH in combination with induced hyperglycemia, hyperoxemia, and chemotherapy was applied. Volume therapy was directed to the PCWP (group A, 8 to 12 mm Hg [20 treatments]), or to ITBVI (group B, 800 to 1,100 mL/m2 [19 treatments]) following a standardized protocol. Goals other than PCWP and ITBVI were cardiac index of > 3.5 L/min/m2 and mean arterial pressure of > 55 mm Hg. MEASUREMENTS AND RESULTS: In addition to the primary goals PCWP and ITBVI, at defined temperatures, central venous pressure (CVP), extravascular lung water index, the number of infusions, and packed RBCs, as well as serum lactate level, norepinephrine dosage, and levels of liver enzymes, bilirubin, creatinine, and urea were measured. Patients in group A received a significantly greater mean (+/- SD) amount of crystalloids compared to those in group B (6,175 +/- 656 vs 3,947 +/- 375 mL, respectively) and required significantly lower dosages of vasoconstrictors compared with patients in group B. Except for the lower values of CVP in patients in group A during hyperthermia, all of the other hemodynamic and laboratory parameters showed no significant differences between the groups or stayed in a normal range. CONCLUSION: PCWP and ITBVI are useful parameters to assess preload in induced WBH. Differences in crystalloids and vasopressor dosages may suggest an appropriate ITBVI of > 1,100 mL/m2 for patients with good cardiopulmonary health under such extremely hypercirculatory conditions.

Blood Volume↗
PubMed2004

CT-guided interstitial brachytherapy of liver malignancies alone or in combination with thermal ablation: phase I-II results of a novel technique.

PURPOSE: To assess the safety and efficacy of CT-guided brachytherapy alone or in combination with laser-induced thermotherapy (LITT) in patients with liver malignancies. METHODS AND MATERIALS: Thirty-seven patients presented with 36 liver metastases and two primary liver carcinomas. Twenty-one patients were treated with CT-guided high-dose-rate brachytherapy alone using a 192Ir source. Sixteen patients received brachytherapy directly after MRI-guided LITT. The indications for brachytherapy alone were a tumor size >5 cm, adjacent central bile duct or adjacent major vessels causing unfavorable cooling effects for thermal ablation, and technical failures of LITT. The dosimetry for brachytherapy was performed using three-dimensional CT data acquired after percutaneous applicator positioning. On average, a minimal dose of 17 Gy inside the tumor margin was applied (range, 10-20 Gy). RESULTS: The mean tumor size was 4.6 cm (range, 2.5-11 cm). The mean liver volume receiving > or =5 Gy was 16% (range, 2-40%) of the total liver. Severe complications were recorded in 2 patients (5%). One patient developed acute liver failure possibly related to accidental continuation of oral capecitabine treatment. Another patient demonstrated obstructive jaundice owing to tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. A commonly encountered moderate increase of liver enzymes was greatest in patients with combined treatment. The local control rate after 6 months was 73% and 87% for combined treatment and brachytherapy alone, respectively. CONCLUSION: CT-guided brachytherapy using three-dimensional CT data for dosimetry is safe and effective alone or in combination with LITT. Brachytherapy as a stand-alone treatment displayed genuine advantages over thermal tumor ablation.

Adult↗
PubMed2004

Response prediction by FDG-PET after neoadjuvant radiochemotherapy and combined regional hyperthermia of rectal cancer: correlation with endorectal ultrasound and histopathology.

Accurate response assessment after neoadjuvant therapy is essential in patients with rectal cancer. The aim of this study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting response of locally advanced rectal cancer to preoperative multimodal treatment. Twenty-two consecutive patients with locally advanced (uT3/4) primary rectal cancer were entered in this prospective pilot study. FDG-PET was performed before and after neoadjuvant radiochemotherapy (RCT) with combined regional hyperthermia (RHT). Treatment consisted of external-beam radiotherapy (45 Gy), chemotherapy (folinic acid and 5-fluorouracil) and regional pelvic hyperthermia followed by curative tumour resection 6-8 weeks later. Semi-quantitative measurements (SUV) of tumour FDG uptake were made before and 2-4 weeks after completion of neoadjuvant treatment. Two patients who did not receive post-therapeutic restaging by FDG-PET were excluded from the analysis. Results were correlated with findings on endorectal ultrasound (EUS, n=17 patients) and histopathology. Histopathological evaluation of the resected tumour revealed complete response in one patient, partial response in 12 and stable disease in seven. SUV reduction in tumours was significantly greater in responders than in non-responders [60% (+/-15%) vs 30% (+/-18%), P=0.003, CI=95%). Using a minimum post-therapeutic SUV reduction of 36% to define response, FDG-PET revealed a sensitivity of 100% (EUS: 33%) and a specificity of 86% (EUS: 80%) in response prediction; the corresponding positive and negative predictive values were 93% (EUS: 80%) and 100% (EUS: 33%), respectively. FDG-PET results were statistically significant (P<0.001, CI=95%). FDG-PET has great potential in the assessment of tumour response to neoadjuvant RCT in combination with RHT and is superior to EUS for this purpose.

Adolescent↗
PubMed2004

Recurrent rectal cancer within the pelvis. A multicenter analysis of 123 patients and recommendations for adjuvant radiotherapy.

BACKGROUND AND PURPOSE: Recommendations for radiation ports in adjuvant radiation therapy for rectal cancer are mainly based on analysis of recurrence patterns. To evaluate whether changes in surgical technique have influenced this pattern of recurrence, a multicenter retrospective analysis was carried out on a patient population treated recently. PATIENTS AND METHODS: 123 patients were evaluated with the help of a CT-based self-developed 3-D data file system and an extensive questionnaire. Major inclusion criteria (one sufficient) for eligibility were: histological confirmation, clear bone destruction, and a positive PET scan, or at least three minor criteria: progressive soft tissue mass, invasion of adjacent organs on follow-up CT or MRI, rising tumor markers, and typical appearance in cross-sectional imaging. Clinical or serologic signs of inflammation were exclusion criteria. RESULTS: Initially, 54% of the evaluated patients were N0; in the remainder, N1 and N2 were distributed evenly. Initial T-category was T1 in 2%, T2 in 24%, T3 in 60%, and T4 in 13%, the male-to-female ratio was 2:1. Recurrent tumors were mainly situated in the posterior part of the bony pelvis as displayed in the figures. When abdominoperineal resection was compared to low anterior resection as primary operation, there was a significant difference in extension of recurrent tumors in the inferior parts of the pelvis (p<0.025 in all statistical tests applied), whereas no significant difference was found in the superior parts of the pelvis. CONCLUSION: Based on these results, a modest field size reduction in adjuvant radiotherapy for rectal cancer seems feasible, offering the perspective of a reduction in acute and late side effects.

Adult↗
PubMed2004

[Influence of preoperative (hyperthermic) radiochemotherapy on manometric anal sphincter function in locally advanced rectal cancer].

BACKGROUND AND PURPOSE: Preoperative radiochemotherapy (RCT) followed by curative surgery is a well-accepted therapeutic option in the treatment of advanced rectal cancer. Usually, the anal sphincter is located in the irradiation area of a preoperative RCT regime. The aim of this study is to evaluate the influence of preoperative RCT on anal sphincter function. PATIENTS AND METHODS: Between 1994 and 2000, 102 patients with rectal cancer stage uT3/uT4 were analyzed. All patients underwent radiotherapy with 45 Gy (5 x 1.8 Gy) including two cycles of 5-fluorouracil (5-FU)/leucovorin (folinic acid) chemotherapy. 46 patients were treated additionally with up to five sessions of locoregional hyperthermia. The sphincter function was analyzed by perfusion manometry before preoperative therapy and 4 weeks after pretreatment had been finished. For statistics, the Wilcoxon signed rank test and Mann-Whitney U-test were used (SPSS 9.0 for Windows((R))). RESULTS: The mean value of all 102 patients showed a significant reduction of the mean maximum resting pressure from 97 to 89 mmHg (p = 0.02). For the mean maximal squeeze pressure no significant difference could be shown (178 vs. 176 mmHg). For patients with distal (</= 7.5 cm from anal verge) tumors the difference was highly significant (92 vs. 79 mmHg). Locoregional hyperthermia had no additional influence on sphincter function. CONCLUSION: Preoperative RCT impairs sphincter function especially in patients with distal tumors. In addition, RCT could have a negative influence on the continence of patients who received sphincter-preserving surgery.

Anal Canal↗
PubMed2004

[CT-Guided brachytherapy. A novel percutaneous technique for interstitial ablation of liver metastases].

PURPOSE: To assess safety and efficacy of CT-guided brachytherapy of liver malignancies. PATIENTS AND METHODS: 21 patients with 21 liver malignancies (19 metastases, two primary liver tumors) were treated with interstitial CT-guided brachytherapy applying a (192)Ir source. In all patients, the use of image-guided thermal tumor ablation such as by radiofrequency or laser-induced thermotherapy (LITT) was impeded either by tumor size > or = 5 cm in seven, adjacent portal or hepatic vein in ten, or adjacent bile duct bifurcation in four patients. Dosimetry was performed using three-dimensional CT data sets acquired after CT-guided positioning of the brachytherapy catheters. RESULTS: The mean tumor diameter was 4.6 cm (2.5-11 cm). The mean minimal tumor dose inside the tumor margin amounted to 17 Gy (12-20 Gy). The proportion of the liver parenchyma exposed to > 5 Gy was 18% (5-39%) of total liver parenchyma minus tumor volume. Nausea and vomiting were observed in six patients after brachytherapy (28%). One patient demonstrated obstructive jaundice due to tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. We commonly encountered asymptomatic increases of liver enzymes. Local control rates after 6 and 12 months were 87% and 70%, respectively. CONCLUSION: CT-guided brachytherapy is safe and effective. This technique displays broader indications compared to image-guided thermal ablation by radiofrequency or LITT with respect to tumor size or localization.

Aged↗
PubMed2004

[Standards and perspectives in locoregional hyperthermia].

The term "hyperthermia" summarises different procedures of raising the temperature of a tumour-loaded tissue to a temperature of 40-43 degrees C. In this context, locoregional procedures (radiative/capacitive local, interstitial and regional hyperthermia; endoluminal hyperthermia), hyperthermic perfusion techniques (hyperthermic peritoneal and isolated limb perfusion), and whole-body hyperthermia differ with regard to their indication, expenditure of application, and evidence of efficacy. All hyperthermia techniques have in common that they have no sufficient antineoplastic activity alone in the temperature range below 43-45 degrees C, but act in a synergistic way with radiotherapy and certain cytotoxic drugs. 14 out of 18 published randomised trials on hyperthermia as an adjunct to standard radio- or chemotherapy refer to locoregional approaches. Particular progress has been made in regional radiofrequency hyperthermia, where novel multiantenna-applicators and their integration into MR-applicators ("hybrid-systems") have recently been introduced into clinical practice. In addition, combinations of hyperthermia with novel technologies (magnetic fluid hyperthermia, thermosensitive liposomes, immunotherapy, gene targeting) are imminent. We here give a critical update on the proven indications of the different locoregional hyperthermia approaches and on the current clinical and technological progress in this field.

Antineoplastic Agents↗
PubMed2004

Clinical and physical determinants for toxicity of 125-I seed prostate brachytherapy.

BACKGROUND AND PURPOSE: To assess acute as well as long-term toxicity after permanent prostate seed implantation. To find predictive clinical or dosimetric factors for side effects in order to work out strategies for improvement. PATIENTS AND METHODS: A group of 174 patients with localised prostate cancer was treated with permanent seed implantation between 1999 and 2001, either alone (140 patients) or in combination with external radiotherapy (34 patients). For the majority (114/174, i.e. 66%) a CT was performed four weeks after implantation and analysed in the planning system VariSeed. In the postimplant analysis, dosimetric descriptors (doses, volumes) were determined for the prostate and rectum and compared with the intraoperative values. In addition, a questionnaire was sent to all patients to assess and quantify acute and chronic toxicity (urinary, rectal, sexual) and the impact on subjective acceptance and quality of life (return rate of questionnaires 83%). The derived score changes were correlated with clinical and dosimetric factors. RESULTS: In the mono-brachytherapy group 14% (16/140) required a bladder catheter, of them 8% (9/140) with a manifest urinary obstruction. Long-term rectal toxicity (<5%) and impairment of potency (<30%) are moderate and obviously below other treatment options. Urinary toxicity is dominant with an overall long-term dysuria up to 30% (at a mean observation interval of ten months), and a significant trend to decline with follow-up time. Conversely, the erectile function tends to deteriorate with follow-up time. Nevertheless, quality of life is not significantly reduced and acceptance is high. Our analysis suggests that the main factor for urinary toxicity and impaired erectile function is the dose load to larger portions of the prostate (D(50)>240 Gy), which appears to be attributed to unnecessarily high numbers of seeds (for a fixed activity per seed) and needles. The rectal toxicity is correlated with the high dose regions in the rectum (>/=145 Gy). Urinary toxicity is lower for combined-brachytherapy, while rectal toxicity and impairment of potency are slightly higher. CONCLUSIONS: Toxicity spectrum and quality of life after permanent seed implantation for early prostate cancer are acceptable for nearly all patients (98%). To further improve tolerance we should attempt to achieve a better dose homogeneity, i.e. by reducing D(50). Therefore, special attention should be given to D(50) during the real-time planning process. The necessity of more homogeneous dose distributions might imply a reduction of the activity per seed, e.g. from 0.7 mCi down to 0.6 mCi.

Aged↗
PubMed2004

123I-IMT SPECT and 1H MR-spectroscopy at 3.0 T in the differential diagnosis of recurrent or residual gliomas: a comparative study.

The aim of this investigation was to compare two current non-invasive modalities, single photon emission tomography (SPECT) using 123-iodine-alpha-methyl tyrosine (123I-IMT) and single-voxel proton magnetic resonance spectroscopy (1H-MRS) at 3.0 T, with regard to their ability to differentiate between residual/ recurrent tumors and treatment-related changes in patients pretreated for glioma. The patient population comprised 25 patients in whom recurrent glioma was suspected based on MR imaging. SPECT imaging started 10 min after iv. injection of 300-370 MBq 123I-IMT and was performed using a triple-head system. The IMT uptake was calculated semiquantitatively using regions-of-interest. 1H-MRS was performed at 3.0 T using the single-volume point-resolved spectroscopy (PRESS) technique. Guided by MR imaging volumes-of-interest for spectroscopy were placed into the suspected lesions. Signal intensities of choline-containing compounds (Cho), creatine and phosphocreatine (Cr), and N-acetylaspartate (NAA) were obtained. When using the cut-off of 1.62 for 123I-IMT uptake, the sensitivity, specificity, and accuracy of the 123I-IMT SPECT were 95, 100 and 96%, respectively. For 1H-MRS, the sensitivity, specificity and accuracy were 89, 83 and 88%, respectively, based both on the metabolic ratios of Cho/Cr and Cho/NAA as tumor criterion with cut-off values of 1.11 and 1.17, respectively. In conclusion, 123I-IMT SPECT yielded more favorable results compared to 1H-MRS at distinguishing recurrent and/or residual glioma from post-therapeutic changes and may be particularly valuable when the evaluation of tumor extent is necessary.

Adult↗