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J Spicka

Publications and source records attributed to J Spicka.

10 recordsLinked to original sources
PubMed1988

Separating output factor into collimator factor and phantom scatter factor for megavoltage photon calculations.

Output factor has been used in megavoltage dosage calculations because collimator factor and backscatter factor are considered individually indeterminable. Output factor reflects the normalized product of backscatter factor and collimator factor for the most common treatment geometry. A method has been found for independently measuring collimator factors for megavoltage photons. Using a build-up cap of high density tissue equivalent material, we have measured the relative collimator factors for various units with photon energies up to 15 MV. Utilizing measured values for output factor and collimator factor relative backscatter factors have been determined.

Humans↗
PubMed1988

Polyethylene-lead tissue compensators for megavoltage radiotherapy.

Tissue compensators afford one the opportunity of producing idealized dose distributions in radiotherapy. We have developed a technique which may be used to produce fast, accurate and inexpensive compensators within a few minutes and requires minimal patient involvement. Three dimensional contour data is acquired using a moire fringe photograph taken at the time of simulation. The photograph is projected to the size needed for the actual compensator and a sketch of the compensator is made. The sketch is placed in a specially designed small portable pantographic unit and the design is traced while the unit cuts the compensator from an indexed polyethylene-lead blank which is premounted on an acrylic tray. The polyethylene-lead material proves to have an ideal combination of properties for compensator construction including relatively high density, ease of machining, good handling characteristics and low cost.

Humans↗
PubMed1975

[Transient infarct-like ECG findings in cholecystectomy].

It is reported on the appearance of transient infarction-like electrocardiographic changes in a 49-year-old female patient which developed during a cholecystectomy after cardiac arrest due to a considerable loss of blood. The ECG normalised within 7 minutes, neither accompained nor followed by any pathologic ion displacements in the systemic blood or by enzyme changes (GOT, GPT).

Cholecystectomy↗