[Burkitt's lymphoma of the caecum as a rare cause of acute abdomen: a case report]. / Burkittuv lymfom céka jako vzácná prímina náhlé príhody brisní--kazuistika.

Burkitt's lymphoma is a highly aggressive B-lymphoproliferative disorder. Clinically it most often manifests with extranodal involvement, typically affecting the gastrointestinal tract as a large and rapidly proliferating tumor mass, which may present as acute abdomen. We present a case report of a young man admitted with signs of acute appendicitis. A tumor of the ileocaecal junction was discovered perioperatively and resolved by a right-sided hemicolectomy. Histological examination of the tumor confirmed Burkitt's lymphoma. On the ninth postoperative day, the patient developed signs of ileus and a follow-up CT scan showed tumor masses in the area of the ileotransversoanastomosis. He was transferred to undergo radical adjuvant chemotherapy. Intestinal passage was restored during the next two days. Our aim is to report on the limited role of surgical treatment in this type of malignancy, due to the extremely rapid proliferation of the tumor tissue, when the tumor can grow back to its original size over a period of a few hours or days.

SU-E-J-97: Evaluation of Multi-Modality (CT/MR/PET) Image Registration Accuracy in Radiotherapy Planning.

PURPOSE: Evaluate accuracy of multi-modality image registration in radiotherapy planning process. METHODS: A water-filled anthropomorphic head phantom containing eight 'donut-shaped' fiducial markers (3 internal + 5 external) was selected for this study. Seven image sets (3CTs, 3MRs and PET) of phantom were acquired and fused in a commercial treatment planning system. First, a narrow slice (0.75mm) baseline CT scan was acquired (CT1). Subsequently, the phantom was re-scanned with a coarse slice width = 1.5mm (CT2) and after subjecting phantom to rotation/displacement (CT3). Next, the phantom was scanned in a 1.5 Tesla MR scanner and three MR image sets (axial T1, axial T2, coronal T1) were acquired at 2mm slice width. Finally, the phantom and center of fiducials were doped with 18F and a PET scan was performed with 2mm cubic voxels. All image scans (CT/MR/PET) were fused to the baseline (CT1) data using automated mutual-information based fusion algorithm. Difference between centroids of fiducial markers in various image modalities was used to assess image registration accuracy. RESULTS: CT/CT image registration was superior to CT/MR and CT/PET: average CT/CT fusion error was found to be 0.64 ± 0.14 mm. Corresponding values for CT/MR and CT/PET fusion were 1.33 ± 0.71mm and 1.11 ± 0.37mm. Internal markers near the center of phantom fused better than external markers placed on the phantom surface. This was particularly true for the CT/MR and CT/PET. The inferior quality of external marker fusion indicates possible distortion effects toward the edges of MR image. Peripheral targets in the PET scan may be subject to parallax error caused by depth of interaction of photons in detectors. CONCLUSIONS: Current widespread use of multimodality imaging in radiotherapy planning calls for periodic quality assurance of image registration process. Such studies may help improve safety and accuracy in treatment planning.

[Unusual approach to a liver metastasis resection]. / Neobvyklý prístup k resekci metastázy jater.

Metastatic disorder is a common finding in patients with abdominal tumors. This case review presents a case of a 52-year old female with a forth relapse of her liver metastasis in the liver segment VIII. The previous procedures used a difficult abdominal approach. In the current procedure, the authors opted for a thoracic transdiaphragmatic approach, which provided perfect view of the site in order to remove the metastasis in the liver segment VIII with partial excision of the adjacent diaphragm. This approach has proved useful in diaphragmatic procedures, as well as in procedures on vascular and biliary structures, as it provides clear view of the operating field.

Evaluation of Web-based computer-aided instruction in a basic science course.

PURPOSE: To demonstrate the applicability of server statistics, in combination with user surveys, to evaluate utilization of Web-based computer-aided instruction (CAI) in the undergraduate medical curriculum. METHOD: Individual user surveys with students' names provided information about computer literacy prior to the course and use of CAI during the course. Utilization of specific web-based CAI developed for the course was recorded by server software and the daily logs correlated with course content. Regression analyses were used to measure correlation of server access logs of individual students versus information from user surveys and performances in the course based on in-course examinations. RESULTS: There was no correlation between computer literacy of students at matriculation and their subsequent levels of use of CAI in the curriculum. Utilization of CAI developed for specific course objectives coincided closely with course content, which is an indication of the effectiveness of the applications in achieving their curricular objectives. In contrast, student use of tutorials coincided most closely with in-course examinations. Students' responses to surveys were generally substantiated by server statistics, but discrepancies were sufficiently large (10% to 20%) to call into question the validity of these surveys. Significant differences in CAI utilization correlated with the performances of students in the course. CONCLUSIONS: This study demonstrates an important advantage of web-based applications to collect and evaluate CAI utilization efficiently and objectively at both the level of the class and the level of the individual student.

Collaboration using Internet for the development of case-based teaching files: report of the Computer and Instrumentation Council Internet Focus Group.

UNLABELLED: The Internet and particularly the World-Wide-Web is becoming a useful tool for the nuclear medicine community. METHODS: The Computer and Instrumentation Council of the Society of Nuclear Medicine convened an Internet Focus group to discuss collaboration using the Internet. The prototype application considered was development of case-based teaching files using the World-Wide-Web. Teaching file cases (clinical history, images, description of findings and discussion) on World-Wide-Web servers at different institutions are integrated using the Internet. The user can navigate from case to case using point-and-click hypertext linking. RESULTS: The initial experience with collaboration has been encouraging. An etiquette to help foster collaboration has been proposed. Development of quality control mechanisms and introduction of peer review were identified as issues needing further work. CONCLUSION: The World-Wide-Web offers great potential for new forms of collaboration. There is, however, a need to learn how to make best use of this new resource.

Photodynamic therapy for intracranial neoplasms: investigations of photosensitizer uptake and distribution using indium-111 Photofrin-II single photon emission computed tomography scans in humans with intracranial neoplasms.

Photodynamic therapy is being investigated as an adjuvant treatment for intracranial neoplasms. The efficacy of this therapy is based on the uptake of photosensitizer by neoplastic tissue, its clearance from surrounding brain tissue, and the timing and placement of photoactivating sources. Photofrin-II is the photosensitizer most actively being investigated. We labeled Photofrin-II with Indium-111 and studied the uptake and distribution of this agent in 20 patients with intracranial neoplasms, using single photon emission computed tomography (SPECT) with volume rendering in three dimensions. Of these patients, 16 had malignant glial tumors, 2 had metastatic deposits, 1 had a chordoma, and 1 had a meningioma. Anatomical-spatial data correlated well between the SPECT images and contrast-enhanced computed tomography or magnetic resonance images. Regions of focal uptake on SPECT images correlated with the surgical histopathological findings of the neoplasm. The kinetics of photosensitizer uptake varied according to the tumor's histological findings, the patient's use of steroids, and among patients with similar types of tumor histology. Peak ratios of target-to-nontarget tissue varied from 24 to 72 hours after injection. The study data show that, to be most effective, photodynamic therapy may need to be tailored for each patient by correlating SPECT images with anatomical data produced by computed tomography or magnetic resonance images. Photoactivating sources then can be placed, using computer-assisted stereotactics, to activate a prescribed volume of photosensitized tumor at the optimal time for treatment.

[Long-term results in the treatment of 100 metastatic hypernephroid carcinomas]. / Langzeitergebnisse bei der Behandlung von 100 metastasierenden hypernephroiden Karzinomen.

The success of renal cell carcinoma (RCC)-nephrectomy with radical lymph node dissection in stage I and II disease is undisputed. Through these measures 23% of metastases are controlled. The five-year survival time in stage III disease, however, stagnates at 35% +/- 14% despite radical surgery. Also, the additional tumor-vaccine-therapy of the Mainz-Joint-Study-Group was successful only in stage I and II disease, whereas stage III disease did not benefit from this therapy. As 50% of all radically operated patients developed metastases within three years after surgery, the call by radio-oncologists for supplementary radiotherapy beginning with stage III disease must be put foreward. The problems of therapy and chances of survival in generalized disease are demonstrated in 100 of our cases treated by surgery, radiotherapy and with MPA (medroxyprogesteroneacetate). Whereas Schmiedt et al. show a total survival time of 10,3 months after diagnosis of metastatic disease, the Offenbach patients achieved 16,5 months with a median survival time of 11,75 months. The necessity of therapeutic intervention is confirmed by the fact that the most favorable median survival time, 15,75 months, was achieved in metastatic disease involving three organs. We present here the special features of the individual organ manifestations and point out that not only the mean and median survival time, but also the very widely varying survival times in individual cases, make conscientious oncological post-treatment follow up and management a requirement.

Errors in the determination of left ventricular functional parameters.

Gated blood-pool scans of the left ventricle are routinely employed for determination of the left ventricular ejection fraction. Recently, attempts have been made to evaluate other left ventricular functional parameters. These values include peak emptying rate (PER), time to peak emptying rate (TPER), peak filling rate (PFR), and time to peak filling rate (TPFR). In studying these parameters clinically, we identified many software errors and assumptions that impact on these values. These errors may also affect the determination of left ventricular ejection fraction (EF). We conclude that before any serious investigation of left ventricular functional parameters is undertaken, a detailed evaluation and standardization of the acquisition and edge detection algorithms must be performed.

Gamma camera radionuclide images: improved contrast with energy-weighted acquisition.

An energy-weighted acquisition (EWA) technique has been developed that utilizes all scintillation events, weighting their contributions depending on their energy, to formulate a radionuclide image. Photopeak events from primary radiation contribute positively; scatter events contribute negatively, providing for scatter subtraction and improved image contrast. EWA is employed with an on-line weighted-acquisition module (WAM) as the data are acquired, rather than as a postprocessing technique. EWA was compared with normal window imaging in patients and in phantoms. For gallium-67 and thallium-201, contrast improved by as much as 40%. A much smaller improvement in contrast was observed with technetium-99m due to its ideal monoenergetic emissions. Single photon emission computed tomographic studies also showed improved contrast and were without artifact. EWA has great promise, and with further development quantitative scatter correction may be possible.

Quality assurance in SPECT imaging.

The predominant type of single-photon emission computed tomography (SPECT) system available today is the rotating gamma camera system. These systems are complex, with many variables to control, and are prone to artifacts. To maintain optimal imaging performance, we emphasize a quality-assurance program that maintains imaging detector performance, proper mechanical alignments, periodic system calibrations, and strict adherence to imaging protocols. We urge the use of SPECT phantoms to evaluate total system performance. With SPECT phantoms, rotating camera systems with both circular and noncircular orbits can be easily evaluated. Quantitative measurements of system performance can be recorded graphically on a time chart for trend analysis, which leads to timely investigation of system failures.

The propagation of stochastic pixel noise into magnitude and phase values in the Fourier analysis of digital images.

The use of Fourier analysis in nuclear medicine gated blood pool ventriculography provides a useful example of the application of Fourier methods to digital medical imaging. In particular, the nuclear medicine experience demonstrates that there is diagnostic significance not only in the pixel averages of temporal Fourier magnitude and phase computed in various image regions, but also in the distributions of the individual pixel values about those averages. However, a region containing pixels that are perfectly synchronous on average would still yield a finite distribution of calculated Fourier coefficients due to the propagation of stochastic pixel noise into the calculated values. We have studied this noise component of both the magnitude and phase distributions using phantom studies and computer simulation. In both approaches, several thousand one-pixel 'ventriculograms' were generated, all identical to each other except for stochastic noise. Fourier magnitudes and phases at several frequencies were calculated and histograms generated. A theoretical prediction of the distributions was developed and shown to fit the experimental results well. Our formalism can be used to estimate study count requirements or, for fixed study counts, to assess the stochastic noise contribution in the interpretation of measured phase and magnitude distributions.

[Hemangiosarcoma of the liver in workers of the PVC industry and other VC-induced diseases with angiologic-dermatologic, hepatologic, radiologic and neurologic symptoms]. / Das Haemangiosarkom der Leber bei Arbeitern in der PVC-Industrie und andere VC-bedingte Erkrankungen mit angiologisch-dermatologischer, hepatologischer, radiologischer und neurologischer Symptomatik.

Occupational diseases resulting from exposure to vinyl chloride (VC) include angiosarcoma of the liver and other neoplasms. Among workers exposed to VC we have found capillary abnormalities in the extremities, with scleroderma and Raynaud syndrome, acro-osteolysis, neurological and psychiatric diseases and chromosome abnormalities, as well as abnormal liver metabolism and haematological findings.

[Radiation oncologic considerations on the treatment of cerebral metastases and personal experiences with 140 cases]. / Radioonkologische Uberlegungen zur Therapie von Hirnmetastasen anhand von 140 eigenen Fällen.

Cerebral metastases appear frequently and necessitate therapeutic measures. The authors report the incidence and particularities as well as the different modes of formation of metastases in the central nervous system. Surgical procedure should be carried out in case of favorable solitary metastases, young patients, and unknown primary tumors. Radiotherapy, which has proved for 30 years to be a valuable treatment method, has to be applied in a modified form in every case. Furthermore, the possibilities of chemotherapy should be studied and applied in a more intensive manner than hitherto. The chance of a one-year survival time is 22 to 44% for those patients presenting with an easily operable tumor. For the total group of radiotherapy patients suffering from various tumor types and generalized metastases, this rate is between 12% and 16%. Despite the short survival times, one should not forget that radiotherapy can produce many successful long-term results in case of cerebral metastases. Therapeutic nihilism is not the right attitude towards this problem.

Validation of 3-deoxy-3-fluoro-D-glucose as a glucose transport analogue in rat heart.

Four aspects of the behavior of 3-deoxy-3-fluoro-D-glucose (D-3FDG) were studied. The distribution of label in rat tissues after intravenous administration of [18F]D-3FDG was compared with that seen with labeled 3-deoxy-3-fluoro-L-glucose (L-3FDG). Results were consistent with a larger volume of distribution for the physiological D-isomer coupled with some degree of reabsorption by the kidneys. L-3FDG, but not its D-isomer, was excluded from the brain. D-3FDG competitively inhibited uptake of glucose by isolated perfused rat hearts. The inhibition constant was 12.8 +/- 1.6 mM compared with 6.1 +/- 1.1 mM for 3-O-methyl-D-glucose. Residue curves obtained after bolus administration of [18F]D-3FDG to isolated hearts indicated phosphorylation of the tracer at a lower rate than for 2-deoxy-2-fluoro-D-glucose but with subsequent dephosphorylation at a faster rate. Chromatographic analysis of 18F remaining in tissues after administration of [18F]D-3FDG revealed in addition to free D-3FDG three other peaks. These disappeared after treatment with alkaline phosphatase and were thus assigned as phosphates. The principal metabolite had the same retention time as D-3FDG-6-phosphate prepared with hexokinase. No phosphorylated metabolites were detected in blood. D-3FDG labeled with 18F may be a useful tracer in studies of glucose transport and metabolism.

[Problems of cervical cancer and presentation of a new ring applicator for the afterloading technic with the selectron]. / Problematik des Kollumkarzinoms und Vorstellung eines neuen Ringapplikators für die Afterloading-Technik mit dem Selectron.

During our radiooncologic experience, we have learned the problems caused by insufficient information on the patient and his tumor. Histologic data, stage and a drawing of the extension of the tumor are generally submitted to the radiotherapist. This study is intended to remind that some other factors are important for the radiooncologic decision about local and temporal dose distribution, such as tumor size, endometrial extension to the fundus, frequency of metastases and recurrences, different histology/grading, and performed surgical technique/radicality. The vital importance of these factors is explained. A new circular applicator is presented for routine afterloading irradiation with the selectron. The applicator has proved to be useful in practice. The problems of the afterloading technique as against the radium technique are indicated, especially with regard to the dose rate in point A.

Phosphorylation of glucose analog 3-O-methyl-D-glucose by rat heart.

When isolated rat hearts were perfused with medium containing 3-O-methyl-D-glucose (3MG) a compound with the chromatographic behavior expected for 3MG-6-phosphate was formed. This assignment is supported by the action of alkaline phosphatase and by production of an identical peak on incubation of 3MG with yeast hexokinase in a buffer containing adenosine triphosphate and Mg++ ions. The clearance of labeled 3MG from isolated perfused rat hearts was biphasic and eventually total. Since sugar phosphates do not cross cellular membranes, this behavior is consistent with both formation and dephosphorylation of 3MG-6-phosphate, with dephosphorylation rate-limiting the slow phase of the clearance. Phosphatase activity was also indicated by a decrease in 3MG-6-phosphate when hearts were not chilled and homogenized immediately after perfusion. The common assumption that 3MG is not metabolized after transport into cells is shown by these experiments to be erroneous.

Alternative approach to single-scan estimation of cerebral glucose metabolic rate using glucose analogs, with particular application to ischemia.

In the glucose analog method for determining local glucose utilization rates, time courses of tissue and plasma radioactivity are measured and then analyzed in terms of first-order exchange of label between tissue compartments. The rate of glucose utilization is assumed to have a fixed, linear relationship to the analog phosphorylation rate calculated from the fitted rate constants. Accurate estimation of the rate constants requires many hours of dynamic data acquisition. Therefore, techniques assuming a linear relationship between analog phosphorylation rate and total tissue concentration of label were developed to predict glucose utilization rates from a single scan. Previously reported linearizations differ in their sensitivity to differences between current and average kinetic rate constants, and thus in their accuracy. We have developed a method that is insensitive to the presumed value of the blood flow-capillary wall transport parameter k1. This new single-scan approach has been validated by comparison of the single-scan metabolic rate values with the values calculated from the dynamic measurements.

Estimation of absolute left ventricular volume from gated radionuclide ventriculograms. A method using phase image assisted automated edge detection and two-dimensional echocardiography.

Twenty-four patients underwent gated cardiac blood pool (GBP) imaging, two-dimensional echocardiography (2-D echo), and single-plane contrast ventriculography (within 24 hours). Variable left ventricular (LV) regions of interest on GBP images were identified by an automated threshold radial search. To avoid excluding LV counts we indexed the search threshold to the threshold identified by a phase image generated by Fourier analysis. LV depth calculated by 2-D echo was used for attenuation correction of LV counts. LV end-diastolic volume (EDV) and end-systolic volume (ESV) were calculated by dividing attenuation, background and deadtime corrected LV count rates by the background corrected count rate/ml of venous blood drawn during the study. Correlations between radionuclide and contrast volumes were good (EDV + ESV r = 0.97, EDV r = 0.94, ESV r = 0.95). Regression lines were close to the lines of identity. This method, in which GBP imaging and automated LV edge finding are complemented by 2-D echo for count attenuation correction, demonstrated reliable and reproducible noninvasive estimates of absolute LV volume.