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Biomedical subjects

R Heyd

Publications and source records attributed to R Heyd.

At least 19 recordsLinked to original sources
PubMed2000

Reconstruction and navigation system for intraoperative brachytherapy using the flab technique for colorectal tumor bed irradiation.

PURPOSE: To present the development of a new navigation and reconstruction system based on an electromagnetic free-hand tracker and on CT imaging for treatment planning of intraoperative high-dose-rate brachytherapy (IORT-HDRB) in the sacral region. Our aim is to improve accuracy and to enable individualized treatment planning and dose documentation to be performed for IORT-HDRB using a flab technique. METHODS AND MATERIALS: The material consists of an electromagnetic 3D tracker system, a PC workstation with Microsoft Windows NT 4.0 operating system, and a recognition program for continuous speech. In addition, we designed an external reference system constructed of titanium and Perspex, which is positioned in the pelvis, and a special digitizer pen for reconstruction of the flab geometry. The flab design incorporates a series of silicon 10-mm-diameter spherical pellets. Measurements were made with a pelvic phantom in order to study the accuracy of the system. The reconstruction results are stored and can be exported via network or floppy to our different treatment planning systems. RESULTS: Our results for the reconstruction of a flab with six catheters and a total of 100 spherical pellets give mean errors in the range (2.5 +/- 0.6) mm to (3.5 +/- 0.8) mm depending on the positions of the pelvic phantom and transmitter relative to the operation table. These errors are calculated by comparing the reconstruction results of our system with those using a CT-based reconstruction of the flab geometry. For the accuracy of the navigation system for the pelvic phantom, we obtained mean errors in the range (2.2 +/- 0.7) mm to (3. 1 +/- 1.0) mm. CONCLUSIONS: The new system we have developed enables navigation and reconstruction within the surgical environment with a clinically acceptable level of accuracy. It offers the possibility of individualized treatment planning and effective documentation of the 3D dose distribution in IORT-HDRB using a flab technique.

Brachytherapy↗
PubMed2000

3D interstitial HDR brachytherapy combined with 3D external beam radiotherapy and androgen deprivation for prostate cancer. Preliminary results.

BACKGROUND: Evaluation of feasibility, tolerance and efficiency for a new 3D interstitial HDR brachytherapy technique combined with 3D external beam radiotherapy and androgen deprivation for prostate cancer. PATIENTS AND METHODS: Between January 1997 and August 1998 we treated 35 patients with stage cT1-3 N0 M0 prostate cancer. Thirty-two patients with a follow-up of 12 to 28 months (median: 18 months) were evaluated. After ultrasound-guided transrectal implantation of 4 non-parallel needles, CT based 3D brachytherapy treatment planning ("Offenbach system") was performed. All patients received 4 fractions brachytherapy using a fractional dose of 5 or 7 Gy. Time between each fraction was 14 days. After brachytherapy 3D external irradiation followed up to 39.6 or 45.0 Gy. All patients received androgen deprivation, starting 2 to 19 months before brachytherapy, ending 3 months after 3D external radiotherapy. RESULTS: Posttreatment PSA levels dropped to < 1.5 ng/ml in 29/32 patients (91%). In 25 patients PSA levels were < 0.5 ng/ml, in 4 patients 0.5 to 1.5 ng/ml. In 2 patients we noted biochemical relapse. Transrectal implantation was very well tolerated. Grade 3 acute urinary toxicity occurred in 1 patient. We noted no Grade 2 or higher acute gastrointestinal toxicity. One patient developed a Grade 3 late urinary toxicity. No patient showed late gastrointestinal side effects. All 140 dose-volume histograms for 3D HDR brachytherapy were analyzed. CONCLUSIONS: The new 3D HDR brachytherapy technique, combined with 3D external irradiation and androgen deprivation, is a feasible, so far well-tolerated and effective treatment in the short-time follow-up of median 18 months.

Adenocarcinoma↗
PubMed2000

Navigation system for interstitial brachytherapy.

PURPOSE: To develop a computed tomography (CT) based electromagnetic navigation system for interstitial brachytherapy. This is especially designed for situations when needles have to be positioned adjacent to or within critical anatomical structures. In such instances interactive 3D visualisation of the needle positions is essential. METHODS AND MATERIALS: The material consisted of a Polhemus electromagnetic 3D digitizer, a Pentium 200 MHz laptop and a voice recognition for continuous speech. In addition, we developed an external reference system constructed of Perspex which could be positioned above the tumour region and attached to the patient using a non-invasive fixation method. A specially designed needle holder and patient bed were also developed. Measurements were made on a series of phantoms in order to study the efficacy and accuracy of the navigation system. RESULTS: The mean navigation accuracy of positioning the 20.0 cm length metallic needles within the phantoms was in the range 2.0-4.1 mm with a maximum of 5.4 mm. This is an improvement on the accuracy of a CT-guided technique which was in the range 6.1-11.3 mm with a maximum of 19.4 mm. The mean reconstruction accuracy of the implant geometry was 3.2 mm within a non-ferromagnetic environment. We found that although the needles were metallic this did not have a significant influence. We also found for our experimental setups that the CT table and operation table non-ferromagnetic parts had no significant influence on the navigation accuracy. CONCLUSIONS: This navigation system will be a very useful clinical tool for interstitial brachytherapy applications, particularly when critical structures have to be avoided. It also should provide a significant improvement on our existing technique.

Brachytherapy↗
PubMed2000

[Radiotherapy in Langerhans-cell histiocytosis. 2 case reports and review of the literature].

The use of radiotherapy in the treatment of Langerhans' cell histiocytosis was first reported in the literature in 1930 and has been proven as effective in numerous studies. We present the results of two female adults with eosinophilic granuloma of bone who underwent conventionally fractionated radiation therapy with total doses of 7 x 1.8 Gy and 7 x 2.0 Gy in four different sites. After observation periods raging from three months to six years local control of the disease was achieved in all treated locations. A review of 18 previously published studies include a total of 310 sites of eosinophilic granuloma of bone in 216 patients. It was demonstrated in 13 studies that the patients had complete relief of symptoms. An average of 94.3% had local control of the symptoms. Furthermore, in 12 studies for a total of 344 cases with involvement of other organs local control was reported in an average of 64.8% (range: 14.3-100%). Based on our own observations and on the literature review we conclude that low dose radiation therapy plays an important role in the management of localised Langerhans' cell histiocytosis. In order to minimise the risk of radiation induced neoplasms an accurate and precise radiation technique is required.

Adult↗
PubMed1999

New interstitial HDR brachytherapy technique for prostate cancer: CT based 3D planning after transrectal implantation.

We have developed a new interstitial HDR brachytherapy technique for the treatment of prostate cancer using CT based 3D planning after transrectal implantation of four non-parallel needles. CT based needle reconstruction, target definition, evaluation and documentation, including DVHs and 3D imaging, is a feasible, safe and well tolerated treatment concept.

Adenocarcinoma↗
PubMed1997

[Radiotherapy of epicondylopathy of the humerus].

OBJECTIVE: To assess the efficacy of radiotherapy in alleviating pain at rest and on exercise in tennis elbow (humeral epicondylitis). PATIENTS AND METHODS: 45 elbow joints in 41 patients were radiated with a telecobalt unit in six sessions at a dose of 1.0 Gy each spread over 3 weeks. Indication for this treatment was pain in the elbow joint at rest, on pressure and on exercise. The patients were re-assessed after a mean follow-up period of 7.5 weeks. They were graded into one of five groups on the basis of their own assessment. Pain on exercise was determined by the Thompson hand-grip, chair test, forced extension and middle-finger stretch test. RESULTS: Satisfactory analgesia was achieved in 31 of 45 elbow joints (68.9%). About 50% of patients still had objectifiable pain on exercise. CONCLUSIONS: Radiotherapy is a highly efficacious means of pain alleviation in tennis elbow, but the results are better for pain at rest than on exercise. The Thompson hand-grip and chair test, positive in more than 90% of patients, proved to be reliable criteria to assess the indications for radiotherapy and its results.

Adult↗
PubMed1997

Can prophylactic application of immunoglobulin decrease radiotherapy-induced oral mucositis?

Therapeutic application of immunoglobulin is reported to be successful in radiation-induced oral and oropharyngeal mucositis. In this study the efficacy of prophylactic application of immunoglobulin was investigated. In 42 patients with head and neck cancer, postoperative radiation treatment or radiation combined with chemotherapy was performed. In 20 consecutive patients, prophylactic mucositis treatment consisted of panthenol (4 x 10 ml/day) and nystatin (4 x 1 ml/day). The 22 following patients received, supplementary to panthenol and nystatin, 800 mg (5 ml) human immunoglobulin intramuscularly once weekly. During the treatment time, the degree of mucositis was examined 3 times a week. The distribution of maximal mucositis degree revealed slightly more severe mucous membrane reaction in the control group compared with the immunoglobulin group (n.s.). The analysis of mean mucositis degrees in both groups demonstrated statistically significant differences (t test, p = 0.031) related to the entire group (n = 42) and to those 16 patients receiving radiation combined with chemotherapy. There was no significant immunoglobulin-induced effect on mucositis in patients treated by radiation alone. The time from the beginning of therapy to the first interruption could be prolonged 5 days in the immunoglobulin group (n.s.). In conclusion, it is demonstrated that the prophylactic application of immunoglobulin seems to lower the degree of radiation-induced mucositis. In comparison to the published data about therapeutically given immunoglobulin, the clinical efficacy of the prophylactic application of immunoglobulin as it is performed in this study is less evident.

Adult↗
PubMed1997

[MRI: incidence and evaluation of size and form criteria in hypophysis-healthy probands and in patients with detectable microadenomas].

Magnetic resonance imaging (MRI) was performed in 42 patients with proven microadenomas and in 42 patients with normal pituitary hormone analysis. The normal MRI--anatomy of the pituitary gland and its possible variations with measurement of the volume and comparison of the anatomy with that of the gland after changes caused by microadenomas has to our knowledge not yet described. In this study we measured the height, coronary and sagittal diameter of the pituitary gland in both groups as well as other indirect signs of microadenomas (asymmetry of the gland, sella turcica, and the stalk). The pituitary volume indicates the expansion of microadenomas much better than the gland height (and the other diameters). Normal pituitary glands showed a significant lower volume (525 +/- 137 mm3 [R = 225-800 mm3]) than patients with proven microadenomas (734 +/- 393 mm3 [R = 335-2800 mm3], p < 0.001). The normal pituitary gland and sella turcica show a large variety of anatomic variations. These variations are less frequent in healthy subjects (10-21%) than in patients with microadenomas (48-71%). The described criteria are of some value in diagnosis of a suspected gland hypertrophy or microadenoma. In 75% of the patients with normal pituitary parameters and in 12% of the patients with microadenomas no indirect adenoma criteria was found in our study.

Adenoma↗
PubMed1997

[Preoperative radiotherapy for prevention of heterotopic ossifications after hip endoprosthesis].

Preliminary results of a prospective study which investigates the efficacy of preoperative radiotherapy (RT) for prevention of heterotopic ossification (HO) after total hip arthroplasty are summarized. A total number of 20 hip joints (18 patients) were irradiated with a single dose of 6.0 Gy < 4 hours before the surgical procedure. After an average observation period of 6.9 months (range: 6-11 months) the results were evaluated using radiological and clinical criteria. At follow-up, one case (5%) had evidence of high-grade HO (> Brooker grade II). The functional outcome quantified with the Harris score was improved by an average of 37.9 points. The authors conclude that preoperative RT is an effective alternative for postoperative irradiation.

Adult↗
PubMed1996

192IR endovascular brachytherapy for avoidance of intimal hyperplasia after percutaneous transluminal angioplasty and stent implantation in peripheral vessels: 6 years of experience.

PURPOSE: Percutaneous transluminal angioplasty (PTA) with or without stent implantation is the accepted standard in the therapy of occlusive arterial disease. Despite improvements in the technique and medical equipment, there is still a restenosis rate of up to 40%. A high-dose-rate afterloading technique to avoid vascular stenosis or occlusion after PTA and subsequent stent implantation caused by intimal hyperplasia is presented with long-term results. METHODS AND MATERIALS: Intravascular brachytherapy with a 10-Ci 192Ir source was performed in cases of recurrent vascular occlusion or stenosis which appeared within 6 months after a previous PTA. After recanalization by PTA and stent implantation, a 9-Fr ReKa catheter was positioned within the stent to center the applicator with its tip 2 cm below the stent. This catheter served as a guide for a 5-Fr flexible applicator. After this procedure the isodose was calculated and a 12-Gy to 3-mm source distance was applied. The procedure was followed by 72 h of heparinization. RESULTS: From May 1990 to June 1996, 28 patients (21 male and seven female) were treated with endovascular brachytherapy. All patients had a clinically relevant restenosis or reocclusion of the arteria femoralis. Follow-up time ranged from 1 to 71 months. Twenty-eight patients had a sufficient follow-up time; 25 of these patients were examined. Twenty-one patients had treated vessel segments; four patients had no flow in the treated area. Two patients moved away with unknown addresses, and one patient died without any follow-up examination. Radiation-associated side effects were not notable. CONCLUSION: Intraluminal brachytherapy with 192Ir is a safe and useful procedure to avoid endovascular hyperplasia after transluminal percutaneous angioplasty.

Aged↗
PubMed1996

[Disseminated pneumoperitoneum during the therapy of lymphoma with methotrexate and cytosine arabinoside].

HISTORY AND CLINICAL FINDINGS: A 58-year-old man was treated for abdominal and inguinal recurrence of a centroblastic non-Hodgkin lymphoma with high doses of methotrexate and cytosine arabinoside. A chest radiogram, taken on the 18th day of chemotherapy to exclude pulmonary infiltration, revealed pneumoperitoneum. The patients's complaints were merely of abdominal fullness and persisting diarrhoea. His general state was hardly impaired, the abdomen soft on palpation with active peristalsis. INVESTIGATIONS: There was aplastic anaemia (haemoglobin 9.9 g/dl, erythrocytes 3.4 x 10(6)/microliters, white cells 1000/microliters, platelets 20,000/microliters. Plain film of the abdomen and abdominal computed tomography confirmed pneumoperitoneum. Intraluminal air had caused wall dissection in the ascending and transverse colon (pneumatosis coli as cause of the pneumoperitoneum). TREATMENT AND COURSE: There was complete absorption of the free abdominal air by the 29th day of chemotherapy under parenteral nutrition and metronidazole (3 x 500 mg daily).

Anemia, Aplastic↗
PubMed1996

[Postoperative radiotherapy in the prevention of heterotopic ossification after endoprosthetic hip joint replacement].

BACKGROUND: Following total hip arthroplasty high-grade heterotopic ossification occurs with a range of 0.5 to 27%. Local postoperative hip irradiation using different dosage and fractionation schedules reduces the incidence in high-risk cases on an average of 8%. The present retrospective study compares results after conventionally fractionated and high-dose radiotherapy. PATIENTS AND METHOD: A total of 50 hips (46 patients) from 2 different risk groups had complete follow-up. In group I (40 hips [80.0%]) radiotherapy was indicated after surgical excision of pre-existing high-grade heterotopic ossification, in group II (10 hips [20.0%]) for several risk factors (contralateral heterotopic ossification [n = 7], hypertrophic osteoarthritis [n = 2], spondylosis hyperostotica [n = 1]). In 28/50 cases (56.0%) conventionally fractionated irradiation with total doses ranging from 12.0 to 20.0 Gy was given, in 22/50 hips (44.0%) a high-dose irradiation consisting of 10.0 Gy given in 2 fractions on each of the first 2 postoperative days was applied. After a minimal observation period of 6 months (median: 22 months, range: 6 to 56 months) roentgenograms were analysed using a modified Brooker score. RESULTS: At follow-up, 2 hips in group I had recurrence of high-grade heterotopic ossification with the stages IIIA and IVB. In 1 case radiotherapy was interrupted after 3 x 2.0 Gy due to sepsis (IIIA), in the other case ectopic bone recurred from bony islands which layed outside the radiation portal (IVB). In group II, 9 patients had stage 0 and 1 patient stage IA. Statistical analysis using the Wilcoxon test showed a highly significant reduction of the amount of pre-existing heterotopic ossification (p < 0.0001) for both fractionation schedules. The comparison of both fractionation groups with the Whitney-Mann-U-test (p = 0.92) showed no statistical significant difference. CONCLUSIONS: The data about the high therapeutic efficacy of postoperative radiotherapy for prevention of heterotopic ossification were confirmed. Both fractionation schedules led to a sufficient reduction of high-grade heterotopic ossification in the 2 treated risk groups.

Adult↗
PubMed1996

[Pneumoperitoneum and pneumoretroperitoneum without perforation].

Asymptomatic radiologically recognised pneumoperitoneum still remains a diagnostic and therapeutic dilemma, because free intraperitoneal air is not necessarily caused by alimentary tract perforation. We present two cases of nonsurgical pneumoperitoneum (caused by pneumomediastinum and pneumatosis intestinalis cystoides) and their typical radiologic findings. Other causes of pneumoperitoneum that do not necessitate laparotomy so as cited in the radiologic and surgical literature are discussed.

Adult↗
PubMed1996

[Universal organ involvement in Rendu-Osler-Weber disease: interdisciplinary diagnosis and interventional therapy].

A case of hereditary hemorrhagic teleangiectasia (HHT, Morbus Rendu-Osler-Weber) in a 63-years-old patient presenting with recurrent gastrointestinal and nasopharyngeal bleeding who required transfusion of 100-200 units of red blood cell concentrate a year is reported. Endoscopically, one source of bleeding could be located in the upper part of the jejunum. Multiple Osler spots were found in the antrum, the bulbal and descending part of the duodenum without signs of bleeding. Colonoscopy revealed no further lesions. Selective mesentericography visualized dilatation of the arterial arcardes in the duodenal region with early venous filling. During coeliacography, parenchymal deposits of contrast medium appeared in the liver. Numerous angiodysplastic arterial alterations from the lower ethmoidal arteria were shown to be another source of bleeding. They were embolized using microspheres and thereby terminating epistaxis. Termination of epistaxis was the crucial prerogative for the consecutive aortal valve replacement. At abdominal ultrasound, the liver harbored multiple anechoic lesions and a bigger cystic formation with portal inflow and early venous distribution. This teleangiectatic portovenous-malformation was confirmed on abdominal computertomography and on T1-enhanced images of MRT, too. This case examplifies the universal character of organ distribution in HHT and underlines the value of complementary diagnostic and therapeutic modalities.

Combined Modality Therapy↗
PubMed1995

[Postoperative, conventional fractionated radiotherapy for prevention of heterotopic ossification after total endoprosthesis of the hip joint].

Radiotherapy is the only local means of treatment in the prevention of heterotopic bone formation. It is possible to reduce the incidence of HO following total hip arthroplasty from an average of 50% without further treatment to an average of 8% using different doses and fractionation schemes. In this retrospective clinical study 22 hips of 20 patients were treated with a conventional fractionated radiotherapy. Total doses of 12.0-20.0 Gy in daily fractionation of 200 cGy single doses were applied 18 hips were postoperatively irradiated as secondary prophylaxis against recurrence of HO. 4 hips were high-risk cases with contralateral HO after previous hip surgery. After 6-30 months observation periods the roentgenogramms were analyzed with a modified Brooker-Score. Patients with a score > II were classified as nonresponders. 95.5% of the treated hips showed satisfactory results, only one hip (4.5%) achieved a score IIIA. In this case radiotherapy was interrupted after 3 x 200 cGy. The high therapeutic efficiency of local irradiation in the prevention of heterotopic bone formation following total hip replacement could be proved. No considerable side effects were observed. Further prospective clinical investigations are necessary to optimize the doses and fractionation schemes.

Aged↗