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H J Feldmann

Publications and source records attributed to H J Feldmann.

At least 37 records · Page 2Linked to original sources
PubMed1998

The value of F-18-fluorodeoxyglucose PET for the 3-D radiation treatment planning of malignant gliomas.

PURPOSE: The aim of the study was to determine the impact of positron emission tomography using the glucose analogue fluorine-18-fluorodeoxyglucose (FDG-PET) on the delineation of the target volume in three-dimensional radiation treatment planning of primary brain tumors. METHODS AND MATERIALS: In 18 patients with histologically proven (8x biopsy, 10x subtotal resection) primary brain tumors (8 astrocytomas grade III, one mixed glioma grade III, and 9 glioblastomas), magnetic resonance imaging (MRI) with gadolinium-DTPA and FDG-PET were performed in radiation treatment position within the same week. A computer program was developed for fusion of the PET and MR images. On corresponding axial slices, FDG uptake was compared to contrast enhancement in T1-weighted and to signal hyperintensity in T2-weighted MR images. Based on PET and MRI data, three-dimensional treatment planning was performed. All patients underwent linear accelerator (LINAC) radiotherapy. RESULTS: In MRI, all tumors and the surrounding edema were visible as hyperintense lesions in the T2-weighted images. 17/18 tumors showed contrast enhancement. In FDG-PET, 16 tumors showed hypermetabolism compared to normal white matter, whereas only 8/18 tumors showed hypermetabolism compared to normal gray matter. White matter edema was associated with decreased FDG uptake in all patients. The area of increased FDG uptake correlated closely with contrast enhancement, only in one case the volume of increased FDG uptake was larger than the area of contrast enhancement. Mean tumor volumes obtained by MRI T1 + Gd, T2, and PET were 30, 106, and 10 ml, respectively. Survival was comparable to data in the literature with a 1-year survival of 39% and a median survival of 310 days. CONCLUSION: Only in a minority of patients did FDG-PET provide additional information for radiation treatment planning. This is mainly caused by the high intensity of FDG uptake in normal brain tissue. PET may be of greater value in the definition of regions that should obtain a radiation dose boost.

Adult↗
PubMed1998

[3-Dimensional irradiation planning in brain tumors. The advantages of the method and the clinical results].

PURPOSE: Radiotherapy became an important component in the treatment of brain gliomas. The aim of this study is to analyse several advantages of the three-dimensional conformal radiation therapy in comparison with a two-dimensional conventional technique and to present the clinical results of 43 patients with brain gliomas treated according to a three-dimensional planning. PATIENTS AND METHOD: Between January 1994 and December 1995, 43 patients with malignant brain gliomas (WHO III and IV) were treated in our department according to a three-dimensional treatment planning. The patients received a total irradiation dose of 60 Gy, 2 Gy/day, 5 days/week. The rate of survival was analysed in relation with the known prognostical factors: histology, Karnofsky index, age, resection status. In 10 patients a three-dimensional treatment planning was compared with a conventional two-dimensional planning: the volume of the normal brain tissue irradiated to high dose levels (95% isodose) and the normal tissue complication probability (NTCP) for the brain by Kutcher and Lyman were comparatively analysed. RESULTS: The survival rate for the whole group was 14 months. The histology of the tumor, age, Karnofsky index and resection status were important prognostical factors. The three-dimensional planning allows a 15 to 20% reduction in the volume of normal brain tissue irradiated to high dose levels (95% isodose). The NTCP is significantly lower using the three-dimensional technique (range 0.03% to 13%), in comparison with the two-dimensional conventional technique (range 0.1% to 26%). The value of NTCP increases with tumor volume. CONCLUSIONS: Concerning the tumor control and survival rate, the three-dimensional treatment planning shows no advantages compared to the standard conventional methods. The main advantage of the three-dimensional treatment planning is the possibility to spare normal brain tissue. The possibility to integrate mathematical models in the evaluation of the therapy could give this technique new dimensions.

Adolescent↗
PubMed1998

[Probability of seminal vesicle involvement in localized prostatic carcinoma. Significance in conformal radiotherapy].

PURPOSE: The development of objective criteria for selecting patients for seminal vesicle irradiation on radical radiotherapy for prostate cancer will be important for successful planning of 3D conformal radiotherapy. MATERIALS AND METHODS: Based on morphometric studies from radical prostatectomy specimens, new imaging modalities with potential in the investigation of patients with gross seminal vesicle involvement and clinical factors with potential in the identification of patients with subclinical disease the development of objective guidelines is possible. RESULTS: Clinical tumor stage as determined by digital rectal examination, diagnostic tumor biopsy (Gleason Score), and pretherapy serum prostate-specific antigen value were significant factors for the probability of involvement of seminal vesicles. Studies show that seminal vesicle involvement is unlikely if the PSA is < 4 ng/ml or 4 to 10 ng/ml and Gleason Score < 7 and stage < or = T2b. In contrast, involvement of seminal vesicles is highly likely with levels above 20 ng/ml. In patients with PSA levels between 10 and 20 ng/ml and Gleason Score < 7 ultrasonographic findings with regard to tumor volume and localization will be useful to determine the extent of the target volume. For treatment planning a significant reduction in the volumes of irradiation to the rectum and bladder is evident when seminal vesicles were excluded. CONCLUSION: Prospective use of the objective criteria will be useful in the selection of patients for seminal vesicle involvement and should be an integral part in 3D conformal radiotherapy of prostate cancer.

Biopsy↗
PubMed1998

[Choroid neovascularization in senile macular degeneration. 1 hear follow-up after radiotherapy].

UNLABELLED: Choroidal neovascularization (CNV) associated with age-related macular degeneration is the major cause of legal blindness in Europe and the USA in patients aged more than 65 years, but Chakravarthy et al. has reported that radiotherapy has a beneficial effect on visual acuity. METHODS: Since March 1996 we have treated 56 patients in cooperation with the Department of Radiotherapy at the Technical University in Munich. The total dose with external beam radiotherapy was 16 Gy in 8 fractions, delivered through an anterior oblique axis to spare the lens. Before the treatment and 3, 6 and 12 months after therapy, we performed a standardized visual acuity and contrast-sensitivity test (ETDRS, Pelli Robson Chard) and fluorescin angiography 6 and 12 months after therapy. RESULTS: Twenty-five angiograms showed well-defined CNV and 31 not well-defined CNV. Six months after the treatment 15 patients had stable visual acuity within one line. Twenty-seven patients had lost more than one line of visual acuity. There was no difference between well and not well defined CNV's. One year after treatment the visual acuity remained stable within one line in 4 patients, no patient had an increase of two lines or more and 17 patients lost more then 2 lines of vision. We saw no side effects other than sicca symptoms in 3 patients. CONCLUSION: In our opinion, these results do not show that radiation treatment has a real beneficial effect on visual acuity. Further randomized studies are needed to demonstrate the efficiency of this treatment for choroidal neovascularization in AMD.

Aged↗
PubMed1998

Changes in tumor oxygenation during combined treatment with split-course radiotherapy and chemotherapy in patients with head and neck cancer.

PURPOSE: To evaluate the changes in tumor oxygenation during definitive split-course radiochemotherapy in locally advanced head and neck cancer (lymph nodes and primaries). MATERIALS AND METHODS: Twenty-four patients with locally advanced head and neck cancer were investigated pretherapeutically and during a defined course of radiochemotherapy (RCTh) with a total dose of 70 Gy given in 35 fractions over 9 weeks (2-week break after 30 Gy). In weeks 1 and 6, the patients received chemotherapy (5 FU and mitomycin C) concomitant with irradiation. The oxygen partial pressure measurements were carried out using polarographic needle probes in combination with a microprocessor-controlled device (pO2 histograph/KIMOC). Times of measurements were before therapy, at the end of week 3 (30 Gy), after a 2-week break (30 Gy) and at the end of therapy if measurable lesion was found (70 Gy). RESULTS: There was a significant reduction in the median pO2 (P < 0.005, n = 18) and an increase in the hypoxic fraction (defined as the percentage of pO2 values of <5 mm Hg) after application of 30 Gy (P < 0.05, n = 18). This effect was partially reversed at the end of the 2-week break. During the break an increase in the median PO2 (P = 0.05, n = 12) and a decrease in the hypoxic fraction could be observed. Towards the end of therapy (70 Gy) a significant decrease (P = 0.02, n = 13) in the median pO2 occurred. Corresponding to this, the hypoxic fraction increased during the last 4 weeks of therapy (P = 0.06, n = 13). CONCLUSION: Statistically significant changes in oxygenation in locally advanced head and neck cancer were found during a split-course radiochemotherapy. This information was obtained in a homogenous group of patients under well-defined therapeutic conditions. The decrease in the tumor oxygenation status at doses of 30 and 70 Gy are important findings because they are in contrast to the concept of continuous improvement of the oxygenation status during fractionated radiotherapy.

Adult↗
PubMed1998

The impact of acute radiation morbidity on therapeutic outcome.

BACKGROUND: The acute radiation morbidity is associated with the radiation therapy outcome. METHODS: To give a summary of the impact of acute radiation morbidity on therapeutic outcome. RESULTS: Excessive acute side effects, most often seen in accelerated or hyperfractionated protocols or in combined radiochemotherapy may lead to interruptions of the radiation cycle and consecutively decreased tumor control rates. They may also result in an increase of consequential late damages. Furtheron, the patient may feel serious discomfort by subjective or objective complaints. CONCLUSIONS: Further national and international efforts have to be performed to lower the acute radiation related morbidity and to increase the effectiveness of radiation treatment.

Humans↗
PubMed1998

Therapy and prophylaxis of acute and late radiation-induced sequelae of the esophagus.

BACKGROUND: Radiation-induced esophagitis is a frequent acute side effect in curative and palliative radiotherapy of thoracal and cervical tumors. Late reactions are rare but might be severe. METHODS: A research for reports on prophylactic and supportive therapies of radiation-induced esophagitis was performed (Medline, Cancerlit, and others). RESULTS: Nutrition must be ensured and symptomatic relief of sequelae is important, especially in the case of dysphagia. The latter can be improved by topic or systemic analgetics. If esophageal spasm occurs, calcium antagonists might help. In case of gastro-esophageal reflux proton pump inhibitors should be used. There is no effective prophylactic measure for radiation esophagitis. Late side effects with clinical relevance are rare in conventional radiotherapy. Chronic ulcera, fistula or stenosis may develop. Before any treatment, a tumor infiltration of the esophagus should be excluded by biopsy. This can lead more often to late complications than radiation therapy itself. Nutrition should be ensured by endoscopic dilation, stent-implantation, or endoscopic percutaneous gastrostomy. Local injection of steroids might be used to avoid an early restenosis. CONCLUSIONS: An intensive symptomatic therapy of acute esophagitis is reasonable. Effective prophylaxis do not exist. Late radiation induced sequelae is rare. Therefore, a tumor recurrence should be excluded in cases of dysphagia. Securing nutrition by PEG, stent, or port is well in the fore.

Amifostine↗
PubMed1998

Radiation proctitis. Clinical and pathological manifestations, therapy and prophylaxis of acute and late injurious effects of radiation on the rectal mucosa.

BACKGROUND: Often the rectum is the dose-limiting organ in curative radiation therapy of pelvic malignancies. It reacts with serous, mucoid, or more rarely bloody diarrhea. METHODS: A research for reports on prophylactic and supportive therapies of radiation-induced proctitis was performed (Medline, Cancerlit, and others). RESULTS: No proven effective prophylactic local or systemic therapies of radiation proctitis exist. Also, no reasonable causal medication is known. In the treatment of late radiation sequelae no clinically tested certain effective therapy exists, too. Antiinflammatory, steroidal or non-steroidal therapeutics as well as sucralfate can be used as topical measures. They will be successful in some patients. Side effects are rare and the therapy is cost-effective. Treatment failures can be treated by hyperbaric oxygen. This will achieve good clinical results in about 50% of the cases. Single or few mucosal telangiectasias with rectal bleeding can be treated sufficiently by endoscopic catheterization. CONCLUSION: Besides clinical studies acute proctitis should be treated just symptomatically. Radical surgery should be performed only when all conventional treatments have been uneffective, although no certain effective therapies of radiation-induced late proctitis exist.

Acute Disease↗
PubMed1998

Relevance of oxygen in radiation oncology. Mechanisms of action, correlation to low hemoglobin levels.

At the beginning of this century Schwarz (1909) and Holthusen (1921) observed the influence of oxygen on the radiosensitivity of cells. In 1951 Hollaender et al. described that E. coli needed 3-fold higher radiation doses when treated under anoxic conditions compared to normoxic conditions. This led to the evaluation of the oxygen enhancement ratio (OER) for photons (X-rays), neutrons and heavy ions. It was found that the OER for conventional radiation therapy (RT) with photons is much higher (about 3) than the OER for neutron-RT (only 1.5) or heavy ions. According to a hypothesis free radicals which are produced by radiation are fixed in the presence of oxygen. Radicals are interacting with DNA, macromolecules and membranes. The DNA lesion can be followed by cell death. There is some evidence that tumor cells respond to hypoxia with the expression of a variety of genes coding for oxygen regulated proteins such as c-jun, VEGF or p53. Hypoxia also enhances the genetic instability of tumor cells. Oxygen tensions in malignant tumors can be determined under clinical routine conditions by using a computerized polarographic needle electrode system (Eppendorf, Hamburg, Germany). Several studies in the past years showed that tumors are in general more hypoxic than the surrounding normal tissue and that a marked variability of intra- as well as intertumoral pO2 values exist (for review see Vaupel and Höckel 1998). Moreover, it has been shown in different tumor entities that the oxygenation status influences the local control rate and overall survival. Furthermore, the oxygenation status obtained at one site (primary) is significantly related at other sites (lymph node metastases) in patients with squamous cell carcinoma of the head and neck (SCCHN). In addition, there is a significant correlation between hemoglobin level and tumor oxygenation in patients with SCCHN. There is some evidence that the oxygenation status can be improved by the correction of a low hemoglobin level and consequently, the curative chance might rise.

Cell Hypoxia↗
PubMed1997

Iridium 192 high-dose-rate brachytherapy--a useful alternative therapy for localized prostate cancer?

We report on a novel protocol involving iridium 192 high-dose-rate brachytherapy and follow-up of up to 130 months in patients with prostatic carcinoma. Using regional anesthesia, five to seven hollow needles are placed within the prostate by perineal puncture under ultrasound guidance. A 9-Gy prostate dose is applied followed by 30 min of hyperthermia (since 1991). This treatment is repeated once after 7 days; 2 weeks later, 18 x 2-Gy external beam radiation (small-field prostate) is added as percutaneous dose saturation. Since 1984 we have treated 40 patients with this protocol. Local tumor control was achieved by means of prostatic biopsy at 18 months after therapy and determination of prostate-specific antigen (PSA) values in about 70% of the patients; after a mean follow-up period of more than 6 years (16-130 months), 80% of the patients show either no evidence of disease or stable disease. We therefore conclude that iridium 192 high-dose-rate brachytherapy is a useful alternative in the treatment of localized prostate cancer in patients who are not eligible for radical prostatectomy.

Adult↗
PubMed1997

Gastric Cancer.

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Antineoplastic Agents↗
PubMed1997

Fluorine-18-FDG PET and iodine-123-IMT SPECT in the evaluation of brain tumors.

UNLABELLED: The high glucose utilization of normal gray matter limits the detection of brain tumor tissue by PET using 18F-fluorodeoxyglucose (FDG). The aim of this study was to evaluate whether the examination of amino acid transport with the SPECT tracer 123l-alpha-methyl-L-tyrosine (IMT) allows better identification of tumor tissue than FDG-PET. METHODS: Nineteen patients (16 with gliomas, 3 with nontumorous lesions) were included in the study. Two independent observers classified PET and SPECT images as positive or negative for tumor tissue and defined the extent of tumor with regions of interest. Tracer uptake of FDG and IMT was quantified by calculating the tumor uptake relative to contralateral gray and white matter. RESULTS: SPECT studies were interpreted concordantly in 18 patients (kappa = 0.77) and all tumors were identified by both observers. PET studies were interpreted discordantly in 4 patients (kappa = 0.52) and only 10 tumors were identified by both observers, interobserver variability in definition of tumor extent was significantly lower in the IMT-SPECT than in the FDG-PET studies (p = 0.03). Mean tumor uptake relative to gray and white matter was 1.93 +/- 0.42 and 2.25 +/- 0.46 for IMT and 0.93 +/- 0.32 and 1.61 +/- 0.52 for FDG. All tumor uptake ratios were significantly (p < 0.01) higher for IMT than FDG, even when only glioblastomas were analyzed. No significant correlation was observed between the various uptake ratios of FDG and IMT. CONCLUSION: Despite the lower resolution and lower sensitivity of SPECT compared with PET, IMT-SPECT was clearly superior to FDG-PET in the detection and delineation of tumor tissue.

Astrocytoma↗
PubMed1996

[Ultrasound volumetry of cervical lymph nodes during radiotherapy as a method of therapy monitoring].

PURPOSE: Volumetric changes of cervical lymph nodes during radiotherapy (RT) should be evaluated with B-mode sonography. It was our intention to test whether ultrasound could be used for therapeutic monitoring. METHOD: 30 lymph nodes of 20 patients were measured. All patients underwent radiotherapy of the cervical region. All lymph nodes were checked at first one day before RT, and then once a week. RESULTS: Concerning the volume change, examined lymph nodes showed great differences. Pretreatment volume ranged from 0.26 to 96.5 cm3, median 4.9. Time volume 50%, i.e. time until volume had decreased by 50%, was reached after 21 (+/-11) days. Mean volume reduction was 1.3 (+/-1.6)% each day. Big lymph nodes needed more time until time volume 50%. Time volume 50% itself correlated positively with the therapeutic outcome. Sonographic lymph node volumetry was useful in 85% of all the patients. CONCLUSIONS: Sonographic lymph node volumetry is a simple and practical method. It can be used easily in clinical routine. Radiotherapist can often gain therapeutically relevant information. We describe the use of sonography for therapy monitoring during RT. This has so far been an unknown potential of the method. However, further evaluation is required.

Adult↗
PubMed1996

[Tissue oxygen partial pressure in human head-neck carcinomas during primary radio-chemotherapy].

BACKGROUND: Experimental data have shown that hypoxic areas in tumors can increase their malignant potential and reduce their sensitivity to chemotherapy and radiation treatment. Until now, the only incomplete data on the oxygenation of human tumors during therapy have been available. METHODS: The distribution of partial pressure of oxygen in malignant head and neck processes was measured in four patients with lymph-node metastases by means of invasive computerized histography (system manufactured by Eppendorf). All patients received primary radiation treatment and chemotherapy with a two-week respite after 30 Gy and the first cycle of chemotherapy. The total dose consisted of 70 Gy in the tumor and two cycles of chemotherapy. Oxygen measurements were taken before the onset of treatment, before and after the respite, and after completion of treatment. RESULTS: In three of the four patients, we measured prominent hypoxic areas in the cancers with PO2 values less than 5 mmHg. The average value was between 12 and 46 mmHg. We were impressed by the observation that oxygenation appeared to improve in every cancer during the respite. Only the patient who showed good initial oxygenation without any measurable hypoxic fraction suffered a complete recurrence six weeks after the completion of therapy. CONCLUSIONS: Prominent areas of hypoxic tissue are present in human head and neck cancers. Radiation treatment and chemotherapy can alter the oxygenation. Further studies are required to investigate the significance of the oxygenation of human head and neck cancers and the changes occurring in it during different types of therapy in order to assess its clinical impact.

Adult↗