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Purpose <p>A benchtop kilovoltage X-ray irradiator was commissioned based on dosimetric parameters, beam quality, and beam profiles. The present study aims to dosimetrically characterize the X-ray beam output in terms of various parameters, namely, tube voltage, tube current, source-to-shelf distance (SSD), beam profiles, congruence of the radiation beam and field size indicators, and beam quality.</p> Methods <p>The effects of tube voltage, tube current, and SSD on dose were measured using the irradiator’s internal parallel-plate ionization chamber. Dose homogeneity, and field size congruence were assessed using radiochromic films. Beam flatness and symmetry were determined by placing radiochromic films on top of a 5-cm-thick polymethyl(methacrylate) (PMMA) phantom, at source-to-phantom surface distances (SPD) of 28&#xa0;cm and 33&#xa0;cm. Beam quality in terms of half-value layer (HVL) was determined using a Farmer-type ionization chamber and aluminum attenuators.</p> Results <p>The irradiator delivered doses that vary linearly with tube current, quadratically with tube voltage, and inversely with the square of SSD. Rotating the turntable improved the transverse beam flatness and symmetry at 28&#xa0;cm SPD by 7.5% and 1.1%, respectively. Moreover, the variances between dose distributions among the film samples in test vessels were reduced to 0.3 to 1.4%. The HVL of Al-filtered beams ranged from 1.10 to 1.80&#xa0;mm Al.</p> Conclusion <p>Results showed the precise radiation doses can be achieved by adjusting tube voltage, current, and SSD settings. Symmetric and flat dose distribution is possible using a turntable at 28&#xa0;cm SPD during irradiation. Dose homogeneity shows variation due to the anode heel effect, but this can be reduced with the rotation of the turntable. A 130-kVp X-ray beam filtered with 0.5&#xa0;mm Al has an HVL of 1.80&#xa0;mm Al and an effective energy of 28.7&#xa0;keV, with enhanced filtration improving X-ray spectrum homogeneity.</p>

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Characterization of beam output, dose homogeneity, and beam quality of a benchtop kilovoltage X-ray irradiator for radiobiology experiments

  • 期刊论文

  • 发表日期：

    2025年4月25日

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  • John Paul C. Cabahug,
  • Shalaine S. Tatu-Qassim,
  • Bernard Isaiah D. Lo,
  • Chitho P. Feliciano

摘要

Purpose

A benchtop kilovoltage X-ray irradiator was commissioned based on dosimetric parameters, beam quality, and beam profiles. The present study aims to dosimetrically characterize the X-ray beam output in terms of various parameters, namely, tube voltage, tube current, source-to-shelf distance (SSD), beam profiles, congruence of the radiation beam and field size indicators, and beam quality.

Methods

The effects of tube voltage, tube current, and SSD on dose were measured using the irradiator’s internal parallel-plate ionization chamber. Dose homogeneity, and field size congruence were assessed using radiochromic films. Beam flatness and symmetry were determined by placing radiochromic films on top of a 5-cm-thick polymethyl(methacrylate) (PMMA) phantom, at source-to-phantom surface distances (SPD) of 28 cm and 33 cm. Beam quality in terms of half-value layer (HVL) was determined using a Farmer-type ionization chamber and aluminum attenuators.

Results

The irradiator delivered doses that vary linearly with tube current, quadratically with tube voltage, and inversely with the square of SSD. Rotating the turntable improved the transverse beam flatness and symmetry at 28 cm SPD by 7.5% and 1.1%, respectively. Moreover, the variances between dose distributions among the film samples in test vessels were reduced to 0.3 to 1.4%. The HVL of Al-filtered beams ranged from 1.10 to 1.80 mm Al.

Conclusion

Results showed the precise radiation doses can be achieved by adjusting tube voltage, current, and SSD settings. Symmetric and flat dose distribution is possible using a turntable at 28 cm SPD during irradiation. Dose homogeneity shows variation due to the anode heel effect, but this can be reduced with the rotation of the turntable. A 130-kVp X-ray beam filtered with 0.5 mm Al has an HVL of 1.80 mm Al and an effective energy of 28.7 keV, with enhanced filtration improving X-ray spectrum homogeneity.