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Biomedical subjects

H Gfirtner

Publications and source records attributed to H Gfirtner.

15 recordsLinked to original sources
PubMed1997

A new Diamentor for measuring kerma-area product and air-kerma simultaneously.

The new M4KDK Diamentor (PTW-Freiburg) for measuring the air-kerma-area product (KAP) and air kerma (AK) simultaneously was evaluated. The special design of the Diamentor chamber influences the variation of the calibration factor with respect to the field size somewhat differently to what is the case with the classic Diamentor. It is therefore recommended that calibration be performed for a larger field size. If the M4KDK Diamentor is calibrated for a field size of 3.8 cm x 3.8 cm (at the chamber), an uncertainty in the AK value of better than 15% for a field size larger than the calibration field, can be expected. The influence of backscattered radiation on the calibration factor is equivalent to that for the classic Diamentor chamber. The variation in response in accordance with tube potential, is also comparable with that of the classic Diamentor. Dramatic changes in response have to be expected if additional filters are introduced in close proximity to the Diamentor chamber.

Biophysical Phenomena↗
PubMed1996

Quality assurance in radiotherapy: the importance of medical physics staffing levels. Recommendations from an ESTRO/EFOMP joint task group.

The safe application of ionising radiation for diagnosis and therapy requires a high level of knowledge of the underlying processes and of quality assurance. Sophisticated modern equipment can be used effectively for complicated diagnostic and therapeutic techniques only with adequate physics support. In the light of recent analyses and recommendations by national and international societies a joint working group of representatives from ESTRO (European Society for Therapeutic Radiology and Oncology) and from EFOMP (European Federation of Organisations for Medical Physics) was set up to assess the necessary staffing levels for physics support to radiotherapy. The method used to assess the staffing levels, the resulting recommendations and examples of their practical application are described.

Europe↗
PubMed1996

[The personnel needs of health physics in radiotherapy].

METHODS AND RESULTS: Using a questionnaire, mean occupation time values for the different medical physics activities were derived in 1992; they formed the basis for recommendations of minimum physics staffing levels in radiotherapy. The recommended staffing levels were compared with the actual staffing levels and to other national and international recommendations.

Germany↗
PubMed1995

[ROKO--computer-assisted roentgen quality control].

To guarantee the quality of 30 x-ray machines and 8 photographic processors 24,000 data are collected yearly. A computer system is introduced (ROKO-Röntgenkonstanzprüfung) which helps to collect the monthly data easily and to measure on-line dose and voltage. If given tolerance values are exceeded acoustic and graphic warnings appear, a trend analysis is made to assure the correctness of the collected data, a generator to design the layout of check form facilitates the controlling and an on-line documentation for each x-ray machine is available. All these features help save time and money.

Computer Graphics↗
PubMed1981

Radiotherapy planning using computed tomography.

A critical look at the use of computed tomography (CT) for radiation therapy planning shows problems which all arise from incorrect positioning of the patient. CT is an excellent tool for therapy planning if the patient is positioned identically at the CT scanner and on the therapy couch. This is accomplished by installing matching laser systems at the CT scanner and at the therapy machine. The authors' planning procedure is discussed in detail.

Humans↗
PubMed1981

[Monitoring of radiation via CT (author's transl)].

The results presented in this article lead to the conclusion that it would be appropriate to demand control or monitoring of radiation via CT whenever complicated exposure to radiation is required. Such control appears mandatory in order to guarantee a sufficiently high tumour dosage and satisfactory protection or minimum burdening of the surrounding tissue. At first sight, it may seem that such CT operations are relatively costly. However, once the teamwork has been properly established, both the time required and the cost involved remain within reasonable limits and will probably not be greater than control via therapy simulator. The decisive factor is that computerised tomography should offer sufficient possibilities of translating such control into reality by effecting the necessary dosage adjustments in accordance with given requirements.

Esophageal Neoplasms↗
PubMed1979

[Therapy planning at the CT (author's transl)].

A therapy planning system was installed in a computer tomography hardware. This configuration has some advantages for treatment planning: 1. CT-images and isodoses can be overlaid. 2. Using skin markers in the computer tomography the actual therapy can easily be checked. 3. This method offers a good method for recording isodoses and anatomic cross sections simultaneously.

Humans↗
PubMed1977

[Computer tomography in therapy planning (author's transl)].

A report is given on the utilization of computer tomography for the irradiation planning. Owing to international cooperation it was possible to use the obtained pictures as a basis for a computerized irradiation planning. The authors give some practical examples of optimized isodose plans for individual cases which have been elaborated by using the computer-tomographic cross-section pictures and the computerized system for irradiation planning and which give a good idea of the efficiency of the system.

Decision Making↗