[Foreign body ingestion in childhood after dental care with rare sequela of perforation of the small intestine and pancreatic injury].
Explore the source record for details and available documents.
Child↗
Biomedical subjects
M W Kellner
Publications and source records attributed to M W Kellner.
[Solid-pseudopapillary tumors in childhood].
We report on fife female patients with solid pseudopapillary tumors of the pancreas. The tumors are extremely rare in children. They occur mainly in adolescent and young adult females. The tumors are neoplasms of low malignancy with infrequent metastases, for instance, in the liver or the peritoneum. Although the tumors had reached a large diameter, all of them underwent complete tumor resection. After that the patients have a very good prognosis. Thus, so it is important to distinguish solid-pseudopapillary tumors from other tumors of the pancreas.
Child↗
[Dosimetry in conventional and spiral CT in 8 spiral CT scanners of the latest generation].
PURPOSE: Measurement of scanner-dependent differences in PCTDI for conventional and spiral CT and evaluation of PCTDI/100 mAs in eight spiral CT scanners of the latest generation. METHODS: Central PCTDI was evaluated in a PMMA phantom for different scan lengths of conventional and spiral CT in four scanners. Central and peripheral PCTDI/100 mAs, average dose and the quotient between peripheral and central PCTDI/100 mAs were measured with a dedicated 10 cm ionisation chamber positioned within a PMMA phantom using the parameters of a standardised liver protocol and a high-resolution inner ear protocol for eight spiral CT scanners. RESULTS: Depending on scanner type and scan length PCTDI for the spiral mode is in a range between 11.3% higher and 4.3% lower than that for the conventional mode. PCTDI/100 mAs varies considerably between different CT scanners. For the standardised liver protocol PCTDI/100 mAs varies up to a factor of 2, for the inner ear protocol up to a factor of 4. CONCLUSION: Even in comparable modern CT scanners there are considerable protocol and scanner-dependent differences in PCTDI/100 mAs. The values for his own scanner should be known to each CT user so that he can develop a dose-optimised, patient and problem-orientated examination strategy.
Ear, Inner↗
Radiation dose and image quality in spiral computed tomography: multicentre evaluation at six institutions.
The purpose of this study was to evaluate the correlation of radiation dose with image quality in spiral CT. Seven clinical protocols were measured in six different radiological departments provided with four different types of high specification spiral CT scanners. Central and surface absorbed doses were measured in acrylic. The practical CT dose index (PCTDI) was calculated for seven clinical examination protocols and one standardized protocol using identical parameters on four different spiral CT scanners with a dedicated ionization chamber inserted into PMMA phantoms. For low contrast measurements, a cylindrical three-dimensional (3D) phantom (different sized spheres of defined contrast) was used. Image noise was measured with a cylindrical water phantom and high contrast resolution with a Perspex hole phantom. Image quality phantoms were scanned using the parameters of the clinical protocols. Images were randomized, blinded and read by six radiologists (one from each institution). PCTDI values for four different scanners varied up to a factor between 1.5 (centre) and 2.2 (surface) for the standardized protocol. A greater degree of variation was observed for seven clinical examination protocols of the six radiological departments. For example, PCTDI varied up to a factor between 1.7 (cerebrum protocol) and 8.3 (abdomen paediatric protocol). Low contrast resolution correlates closely with dose. An improvement in detection from 8 mm to 4 mm sized spheres needs approximately a ten-fold increase in dose. Noise shows a moderate correlation with PCTDI. High contrast resolution of clinical protocols is independent of PCTDI within a certain range. Differences in modern CT scanner technology seem to be of less importance for radiation exposure than selection of protocol parameters in different radiological institutes. Future discussion on guidelines regarding optimal (patient adapted) tube current for clinical protocols is desirable.
Brain↗