An Automatic Scanning and Printing Analog-to-Digital Densitometer

Journal Article · Mon Jan 01 04:00:00 EST 1962 · IRE Transactions on Bio-Medical Electronics

DOI:https://doi.org/10.1109/TBMEL.1962.4322967· OSTI ID:4636475

Gatzek, H. F.; Gordy, E.; Hasenpusch, P.

An instrument for calculating dose distribution in supervoltage radiotherapy is described and illustrated. The instrument automatically extracts the pertinent dose information of closely spaced density measurements on film. These measurements are translated into discrete dose levels in 10% increments which are digitally printed by means of an electric typewriter. The typewriter provides the mechanical scanning of the film, as well as the digital printout. For use with film densitometry, body phantoms representing the patient were constructed. This was done by making radiographic cross sections with a transverse laminagraph at 1-in. intervals. After reducing the films to 1: 1 scale with a camera lucida, they were cut out of tissue-equivalent wax plates and put in register. The phantom thus obtained represents the patient and body fluids which might alter the position of the tumor and affect the uniformity of dose distribution. To measure the dose distribution occurring under different conditions, film densitometry was chosen as the most suitable method, but this procedure will be superseded in the future by density measurement in plastic sheets. Films sandwiched between 2 adjacent cross-sections of the phantom were exposed to supervoltage radiation and the resulting blackening of the emulsion, which is related to the delivered dose, has been measured and plotted with the instrument described above. This instrument eliminates the manual work of measuring and plotting densities of the films and enables rapid and automatic estimation of dose distribution in the phantom at several levels. It provides a quantized analog presentation (the typographic pattern forming the isodose contours) as well as a point-by-point digital presentation. Superposition of an anatomical overlay permits direct read-off of radiation dose to any organ present in the cross-section being studied. The instrument, because of its simple, accurate, automatic, rapid operation makes film dosimetry for supervoltage therapy practical on a clinical application basis.

• Research Organization: Roswell Park Memorial Inst., Buffalo
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-036056
• OSTI ID: 4636475
• Journal Information: IRE Transactions on Bio-Medical Electronics, Journal Name: IRE Transactions on Bio-Medical Electronics Journal Issue: 2 Vol. 9; ISSN 0096-1884
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
BODY
CAMERAS
DETECTION
DIGITAL SYSTEMS
DISTRIBUTION
IMAGES
INSTRUMENTS
MAN
MATHEMATICS
MEASURED VALUES
MOCKUP
PARAFFIN
PHOTOGRAPHIC FILM
RADIATION DOSES
RADIOGRAPHY
RADIOTHERAPY
RECORDING SYSTEMS
SENSITIVITY
TISSUES
X RADIATION