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Biomedical subjects

H P Busch

Publications and source records attributed to H P Busch.

At least 37 records · Page 2Linked to original sources
PubMed1995

Digital radiography: comparison of different methods for imaging of the thorax and the gastrointestinal tracts.

In evaluating the image quality of the chest, four different analog and digital methods were compared. For peripheral lung field, the advanced multiple beam equalization radiography (AMBER) system was given the best score, followed in order by the storage-phosphor, conventional, and asymmetric film/screen systems. For the mediastinal field, the highest image quality was given to the AMBER system, followed by storage phosphor and asymmetric film/screen system. The best overall image quality, especially with regard to demonstration of pathologic alteration, was given to the AMBER system, followed by the storage-phosphor, conventional, and asymmetric film/screen radiography systems. In conclusion, AMBER demonstrated the highest image quality. The storage-phosphor system provided better results in the peripheral and mediastinal fields in comparison with conventional film/screen systems. Other digital systems including selenium chest radiography system and image intensifier digital radiography were also discussed.

Bone and Bones↗
PubMed1994

The contrast-detail behaviour of a photostimulable phosphor based computed radiography system.

Contrast-detail measurements were performed on a computed radiography imaging system as a function of detector entrance air kerma over the dose range from 0.743 microGy (0.085 mR) to 277 microGy (31.8 mR). A theoretical model of contrast-detail behaviour for a photostimulable phosphor computed radiography system has been derived, which is based on a modified version of the Rose theory of threshold detection. Included in the model are both system and x-ray quantum noise terms, as well as the response of the eye. The zero-frequency noise power of the computed film images was measured with a double-beam scanning microdensitometer. For a given detector dose, good agreement was found between the predicted and measured data when this measurement of system noise was included in the model. The contrast-detail results obtained for the computed radiography system were also compared with contrast-detail results for an image intensifier-TV based digital imaging system and a conventional film-screen system.

Air↗
PubMed1994

An investigation into the radiation dose associated with different imaging systems for chest radiology.

With the advent of digital imaging there now exists a range of imaging techniques which may be used to acquire chest images. The purpose of this investigation was to determine typical radiation doses associated with the use of a conventional film-screen system, 100 mm film technique, large-field digital image intensifier radiography, computed radiography and a scanning slit system (AMBER, Oldeft, Netherlands). Radiation doses to relevant organs were assessed using direct measurements made with lithium fluoride thermoluminescent dosemeters, together with calculations made using normalized dose data. Typical doses were assessed using anthropomorphic phantoms for both postero-anterior and lateral projections. The risk-related quantities, i.e. effective dose and effective dose equivalent, were then calculated from these organ doses. When compared on the basis of effective dose equivalent, certain imaging techniques were seen to offer the potential for significant dose reduction, possibly at the expense of image quality.

Humans↗
PubMed1994

A comparison of radiation dose in examination of the abdomen using different radiological imaging techniques.

Typical radiation doses for abdominal examinations were determined for field sizes and entrance doses commonly selected on image intensifier based digital radiographic systems. In addition, measurements were also performed using conventional film-screen methods, a 100 mm camera combination and a phosphor storage computed radiography system. Both antero-posterior and postero-anterior projections were assessed. An anthropomorphic phantom loaded with lithium fluoride thermoluminescent dosimeters was used to measure entrance surface doses. Organ equivalent doses, deduced using normalized organ dose data, were used to calculate effective dose and effective dose equivalent. A comparison of the imaging techniques on the basis of effective dose indicated that significant dose reductions (by approximately a factor of 3) may be expected if the abdomen is imaged using a postero-anterior rather than an antero-posterior projection for a given imaging system. If digital imaging systems are used instead of a conventional film-screen technique, patient effective dose for a given projection can be lower by at least a factor of 5.

Abdomen↗
PubMed1993

Digital fluoroscopic radiology: evaluation of the clinical impact.

The use of digital image intensifier radiography (DIIR) for examinations in projection radiography is becoming more common. Fluoroscopic controlled contrast studies (barium- or iodine-based), particularly of the gastrointestinal tract, can be performed quickly and easily with a considerable decrease in radiation exposure. A wide dynamic range permits a constant high image quality with fewer incorrect exposures. The limited spatial resolution of large image intensifier input screens is the major drawback of DIIR. Digital image acquisition enables post-processing, digital storage and transfer of images, thus allowing an integration into PACS-systems. Imaging capabilities and clinical applications are described here.

Contrast Media↗
PubMed1993

[New imaging methods in thoracic diagnosis. A study to evaluate digital storage screen radiography, the slit technique ("AMBER"), asymmetric ("InSight") and conventional film-screen techniques].

New methods have been introduced in recent years in chest imaging to achieve high image quality simultaneously in the mediastinum and in the lung field. In this study the clinical value is assessed for four techniques: digital storage phosphor radiography, slit-technique ("AMBER"), asymmetrical film/screen ("InSight") and conventional film/screen. 43 patients were examined with these techniques within one day. Seven readers of four universities graded the image quality according to ten criteria of the mediastinum and the lung field. The slit-technique ("AMBER") showed the best image quality in both areas. Compared to conventional film/screen, storage phosphor radiography and asymmetrical film/screen ("InSight") yield better image quality only in the mediastinum.

Adult↗
PubMed1993

[New analog and digital imaging techniques for chest diagnosis--principles--clinical value--economics].

For chest imaging new analog and digital imaging techniques are now available. In this publication the imaging methods conventional film/screen, asymmetric film/screen("In-Sight"), slit(AMBER)-technique, spotfilm(100 mm)-technique, storage phosphor radiography and digital image intensifier radiography are compared. The clinical value is discussed by measured imaging capabilities and patient examinations. The highest image quality was demonstrated by the slit(AMBER)-technique. In comparison to conventional film/screen, storage phosphor radiography and asymmetric film/screen was graded higher only in the mediastinal field. Because of the low spatial resolution the image quality of digital image intensifier radiography was classified too poor for chest imaging.

Germany↗
PubMed1992

[Thoracic radiographs with the AMBER system. A comparison of the diagnostic image quality of film-screen and storage-phosphor radiographs on the grid-partition stand and the AMBER system].

Since April 1990, chest radiographs in the Mannheim clinic have been performed with a slit technique (Kodak AMBER System). In this study, image quality from conventional film/screen combination and from storage phosphor radiography was compared with that from the AMBER system. Phantoms were used to measure spatial resolution and to determine the detectability of nodules. Image quality affecting various structures within the thorax was evaluated on 200 p.a. and 48 lateral radiographs by three radiologists from Mannheim and four from Berlin. In the retrocardiac, retrodiaphragmatic, mediastinal and peripheral portions the best image quality was obtained by film/screen with the AMBER system. Compared with conventional film/screen images, there was no improvement from the AMBER system within the lung parenchyma. The use of storage phosphor plates with the AMBER system did not lead to any further improvement in image quality.

Evaluation Studies as Topic↗
PubMed1992

[Detection of a pheochromocytoma in the urinary bladder wall].

We present the case of a 23-year old female patient with clinical signs and biochemical results of a pheochromocytoma. Abdominal ultrasound gave no hints on localisation. Angiography demonstrated a richly vasculated tumour in the region of the superior urinary bladder. Computed tomography (CT) was able to localise the tumour but could not differentiate the tumour origin in bladder or uterus. The selective venous catheter blood sampling confirmed the localisation of the norepinephrine producing pheochromocytoma in the inferior pelvic region. Intraoperative diagnosis turned out to be an extra-adrenal pheochromocytoma of unknown tumour status in the dorsal bladder wall.

Adult↗
PubMed1992

[The treatment of bile duct stenoses using metal mesh endoprostheses (stents)].

Transhepatic biliary drainage is an established therapy for the palliative treatment of biliary stenosis. Long-term biliary drainage may be accomplished by the introduction of an endoprosthesis. Plastic endoprostheses are, however, prone to clogging and dislocation. A new type of endoprosthesis consisting of an expandable metallic mesh has, therefore, been developed. Results in 51 patients using two different types of metallic stents demonstrated that the technical success rate is higher with self-expanding stents than with balloon-expandable stents. Symptoms of obstructive jaundice were effectively palliated in the vast majority of patients (80%). Reobstruction during the first 4 weeks occurred in only 1 patient. Malfunction was related to the inappropriate length of the stent. At follow-up, 25% of patients with malignant biliary strictures developed recurrent jaundice, which was controlled by a single additional placement of a stent or a plastic endoprosthesis. In conclusion, although recurrent biliary stenosis is still a problem, the frequency of reinterventions can be considerably reduced by the use of metallic instead of plastic endoprostheses (20% vs. 45%).

Aged↗
PubMed1992

[Digital image intensifier radiography--what dose for what clinical problem?].

Due to a wide dynamic range it is possible to vary the dose of DIIR for each type of examination according to the required image quality. To define the possible decrease of dose compared to film-screen radiography (speed 200) the dependence of spatial resolution and contrast detectability upon dose was evaluated. We used a Polytron 1000 which was connected to a Siregraph D and an Optilux 57 (Siemens). Acquisition parameters were fixed for different types of examination and tested by imaging anthropomorphic phantoms as well as patients (n = 114). Our results demonstrate that the dose can be reduced by 60% for double-contrast examinations and by 85% for mono-contrast studies. Although DIIR is less suited for chest and skeletal imaging, a 14 cm image intensifier can be used for imaging small lesions. If poor image quality is acceptable (e. g. pelvimetry, sometimes in paediatrics), a maximum reduction of 95% is possible.

Humans↗
PubMed1991

[The value of digital imaging techniques in skeletal imaging].

The clinical value and the imaging characteristics of digital radiography systems (image intensifier (I.I.) radiography: Polytron/Siemens, storage phosphor radiography: PCR/Philipps) in skeletal imaging were compared with film-screen radiography and 100 mm technique. The influence of spatial and contrast resolution, entrance dose and detectability of lytic, osteoblastic and cortical lesions were studied as well as the images of 25 parallel examined patients. Only with the small image intensifier (diameter 14 cm) the quality of 100 mm technique and digital I.I. radiography was equivalent to storage phosphor and film-screen radiography. Storage phosphor radiography seems to be better qualified than I.I. radiography to replace conventional techniques in skeletal imaging.

Bone Neoplasms↗
PubMed1991

[Digital thoracic radiography--a comparison of digital and analog imaging techniques].

New analog and digital imaging techniques for the chest became available in recent years. In this study conventional film/screen radiography was compared with slit technique ('AMBER'), storage phosphor radiography and digital image intensifier radiography by phantom exposures and patient examinations. Because of its low spatial resolution, quality of digital image intensifier radiography was insufficient for chest imaging. The slit technique demonstrated the highest image quality, especially in the fields of the mediastinum and the thoracic wall. In comparison to conventional film/screen radiography, storage phosphor radiography had advantages in the mediastinal field. Digital techniques are connected to new possibilities of image post-processing, storage and transfer. For difficult conditions of exposure (emergency unit) over- or underexposed images can be avoided by these new digital techniques. The combination of slit- and storage phosphor-technique did not increase image quality.

Analog-Digital Conversion↗