Integral Absorbed Doses in Roentgen Diagnostic Procedures: I. The dosemeter

Carlsson, Christina

doi:10.3109/02841866509133105

Cited by 20 publications

(16 citation statements)

References 13 publications

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“…Too large an ion chamber reading may also be found due to registered back scattered photons from the patient or tablecouch if the distance between the chamber and any scatter ing material is not large enough (5,27). The increase in chamber reading can be as large as 35% with direct contact between chamber and backing material but decreases rapid ly to a negligible value at 30 cm.…”

Section: Methodsmentioning

confidence: 97%

“…ROSENSTEIN et al (25) used 3 sizes of phantoms, representing the ages: newborn, 1 year, and 5 years; CRISTY et al (7) newborn, 1,5,10, 15 year and adult; and VEIT et al (30) phantoms based on CT images from 2 children, 2 months, and 7 years old. Our previously published conversion factors between the energy imparted and air collision kerma integ rated over beam area using brick-shaped phantoms repre sentative for an adult (2) have now been extended to include children.…”

mentioning

confidence: 99%

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Conversion Factors between Energy Imparted to the Patient and Air Collision Kerma Integrated over Beam Area in Pediatric Radiology

Persliden¹,

Sandborg²

1993

Acta Radiol

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Conversion factors between the energy imparted to the patient in pédiatrie radiography and air collision kerma integrated over beam area are presented. The values have been derived from Monte Carlo calculations in soft tissue phantoms and extend results published earlier to cover children from early infancy to the age of 15 years. Variations related to phantom size as well as to focus-phantom distance, radiation field size, orientation of view (a.p., lateral), tube potential, and beam filtration are given. We show that the conver sion factor increases with increasing half-value layer of the Xray beam and the anterioposterior width of the simulated child. Increasing the focus-phantom distance increases the conversion fac tor, while increasing the field size decreases the factors due to more scattered radiation escaping laterally from the phantom.In optimizing pédiatrie radiography, the image quality and the risk to the child from the irradiation are of interest (10). The degree of correlation of the concept "energy im parted to the patient" (22) to risk may in many cases be just as good as that of the more complicated estimate of effective dose (1,27). Tissue weighting factors (w T ) for calcu lation of effective dose (E) (23) for different organs have been published for a population comprising equal numbers of both sexes. So far, however, tissue weighting factors for children have not been published; nor have values been adopted by the International Commission of Radiation Pro tection (ICRP) (9). ICRP states that data applicable for adults are not generally applicable to children. Furthermore, as compared to E, the energy imparted to the patient (ε) and the mean absorbed dose (ε/m; m = patient mass) will not change with time as knowledge of the radiosensitivities of organs increases and are also less dependent on exact knowledge of field position and field size. In practice, a transparent ion chamber is placed in the irradiation field close to the beam diaphragm to measure the air collision kerma, K cair) integrated over beam area. These measure ments together with conversion factors can give the energy imparted to the patient, which in turn is related to the risk.Conversion factors based on human shaped phantoms for use in calculating absorbed dose in specified organs for pédiatrie radiology have been published (7,25,30). ROSENSTEIN et al. (25) used 3 sizes of phantoms, representing the ages: newborn, 1 year, and 5 years; CRISTY et al. (7) newborn, 1,5,10, 15 year and adult; and VEIT et al. (30) phantoms based on CT images from 2 children, 2 months, and 7 years old. Our previously published conversion factors between the energy imparted and air collision kerma integ rated over beam area using brick-shaped phantoms repre sentative for an adult (2) have now been extended to include children. The conversion factors are derived using Monte Carlo calculations in soft tissue phantoms corresponding in size to children from the newborn to 15 years of age.

show abstract

Section: Methodsmentioning

confidence: 97%

mentioning

confidence: 99%

Conversion Factors between Energy Imparted to the Patient and Air Collision Kerma Integrated over Beam Area in Pediatric Radiology

Persliden¹,

Sandborg²

1993

Acta Radiol

View full text Add to dashboard Cite

show abstract

“…Too large an ion chamber reading may also be found due to registered back scattered photons from the patient or tablecouch if the distance between the chamber and any scattering material is not large enough (5,27). The increase in chamber reading can be as large as 35% with direct contact between chamber and backing material but decreases rapidly to a negligible value at 30 cm.…”

Section: Methodsmentioning

confidence: 99%

Conversion Factors between Energy Imparted to the Patient and Air Collision Kerma Integrated Over Beam Area in Pediatric Radiology

Persliden¹,

Sandborg²

1993

Acta Radiol

View full text Add to dashboard Cite

“…1, the voltage across the condenser, is approximately proportional to the areal exposure measured in R cmz. The integral dose can be calculated from the graph, as reported in part I of this article ( CARLSSON 1965). The relative contribution of the roentgenograms to the integral dose will then be about 1.4 times greater than indicated in Fig.…”

Section: Colon (Barium Enema)mentioning

confidence: 99%

Integral Absorbed Doses in Roentgen Diagnostic Procedures: I. The dosemeter

Cited by 20 publications

References 13 publications

Conversion Factors between Energy Imparted to the Patient and Air Collision Kerma Integrated over Beam Area in Pediatric Radiology

Conversion Factors between Energy Imparted to the Patient and Air Collision Kerma Integrated over Beam Area in Pediatric Radiology

Conversion Factors between Energy Imparted to the Patient and Air Collision Kerma Integrated Over Beam Area in Pediatric Radiology

Integral Absorbed Doses in Roentgen Diagnostic Procedures: II—Measurement of integral doses in two roentgen diagnostic departments

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