Siemens teletherapy caesium unit
| Autor: | M. P. Casebow, J. M. Brindle, R. C. T. Buchan, P. L. Ormsby |
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| Rok vydání: | 1974 |
| Předmět: | |
| Zdroj: | The British Journal of Radiology. 47:913-915 |
| ISSN: | 1748-880X 0007-1285 |
| DOI: | 10.1259/0007-1285-47-564-913 |
| Popis: | The purpose of this communication is to report the main physical characteristics of a Siemens “Caesa-Gammatron” teletherapy unit modified to operate at 30 cm and 50 cm SSD. Caesium-137 obtained from Radiochemical Centre Limited. Nominal 3,500 curies and 11 RMM. Active diameter 3·2 cm. Active length 6·04 cm. The unit was supplied with a block collimator with field size scales for fields at 25 cm and 40 cm SSD, the 50 per cent penumbra levels being used to define field size. Since at 25 cm SSD the clearance between collimator face and patient is only 8middot;5 cm, a basic SSD of 30 cm was chosen in order to provide space for accessories. The second standard SSD was increased from 40 cm to 50 cm in order to achieve adequately large field sizes. The collimator field size scales were re-calibrated accordingly, the opportunity being taken to use the 80 per cent penumbra level for field size definition to conform with the practice on other teletherapy isotope units in the department. |
| Databáze: | OpenAIRE |
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