Monte Carlo simulations of a kilovoltage external beam radiotherapy system on phantoms and breast patients

Breitkreutz, D.; M, Weil; Zavgorodni, Sergei; Bazalova‐Carter, Magdalena

doi:10.1002/mp.12619

Cited by 14 publications

(21 citation statements)

References 18 publications

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“…Figure shows that the primary difference between the KVAT and VMAT breast treatment is the homogeneity of the dose within the lesion. The KVAT plan produced regions of higher dose within the PTV due to the overlap of the beamlets, a phenomenon which has been observed in previous work . This is not of concern as there has been evidence that a heterogeneous dose within the PTV may not be detrimental .…”

Section: Discussionsupporting

confidence: 59%

“…Figure is a rendering of one potential design of the KVAT system and illustrates the x‐ray source mounted on a slip‐ring gantry and the location of the patient on the treatment couch. Figure is a modified image from our previous work and illustrates the geometry of the KVAT transmission source and the geometry of KVAT radiation delivery. The x‐ray source MC model consists of a 60‐cm by 1‐cm tungsten transmission anode with an electromagnetically steered electron beam running at 200–225 keV for radiation therapy as well as lower energies for imaging.…”

Section: Methodsmentioning

confidence: 99%

“…The KVAT plan produced regions of higher dose within the PTV due to the overlap of the beamlets, a phenomenon which has been observed in previous work. 9 This is not of concern as there has been evidence that a heterogeneous dose within the PTV may not be detrimental. 31 We can also observe from Fig.…”

Section: A Analysis Of Dose Distributionsmentioning

confidence: 99%

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Inverse optimization of low‐cost kilovoltage x‐ray arc therapy plans

Breitkreutz¹,

Renaud

Seuntjens

et al. 2018

Medical Physics

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Section: Discussionsupporting

confidence: 59%

Section: Methodsmentioning

confidence: 99%

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Inverse optimization of low‐cost kilovoltage x‐ray arc therapy plans

Breitkreutz¹,

Renaud

Seuntjens

et al. 2018

Medical Physics

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“…The above found dose rate can be compared, albeit roughly, to the simulated MC findings previously published for a 16.2 cm diameter water phantom. 13 In that study, the dose rate at 200 kV, 200 mA was found to be just over 150 cGy/min for a 4 cm lesion at the center of a 16.2 cm cylindrical water phantom. 13 Given the estimate dose rate as described above as shown in Figure 10, found as 66 cGy/min for 15.6 cm acrylic phantom at 145 kV, the dose rate is lower than the simulated values.…”

Section: Discussionmentioning

confidence: 88%

Dosimetry of a novel converging X‐ray source for kilovoltage radiotherapy

Stalbaum¹,

Partain²,

M³

et al. 2021

Medical Physics

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Purpose:The objective of this work was to evaluate phantom dosimetry of a novel kilovoltage (kV) X-ray source, which employs a stationary tungsten anode and a linearly swept scanning electron beam. The source utilizes converging Xray collimation along with orthogonal mechanical rotation to distribute surface flux over large area. In this study, this was investigated as a potential solution to fast-falloff limitations expected with kV radiotherapy. This was done with the aim of future clinical development of a lower cost radiotherapy alternative to megavoltage (MV) linac systems. Methods: Radiochromic film was employed for dosimetry on the kV X-ray source of the linear-converging radiotherapy system (LCRS). The source utilizes charge particle optics to magnetically deflect and focus an electron beam along a stationary, reflection tungsten target in an ultra-high-vacuum stainlesssteel chamber. Resulting X-rays were collimated into converging beamlets that span a large planar angle and converge at the system isocenter. In this study, radiochromic film dosimetry was done at 140 and 145 kVp for a designated planning treatment volume (PTV) of 4 cm diameter. An acrylic phantom was employed for dose distribution measurements of stationary and rotational delivery. Film dosimetry was evaluated in planes parallel to the source X-ray window at various depths, as well as in the plane of gantry rotation. Results: At 140 and 145 kVp and using a collimated 4 cm square field at depth, lesion-to-skin dose ratio was shown to improve with additional beams from different relative source positions, where the different beams are focused at the same isocenter and do not overlap at the phantom surface. It was only possible to achieve a 1:1 D max -to-surface ratio with four delivery beams, but the ratio improved to 4:1 with 12 beams, focused at the same isocenter depth of 7.8 cm in an acrylic phantom. For the tests conducted, the following D max -to-surface ratios were obtained: 0.4:1 lesion-to-skin ratio for stationary delivery from one entry beam, 0.71:1 lesion-to-skin ratio was obtained for two beams, 1.07:1 ratio for four beams, and 4:1 for 12 beams. Dose-depth profiles were evaluated for stationary and rotational dosimetry. Additionally, rotational dosimetry was measured for a case more analogous to a clinical scenario, where the isocenter was located at an off -center simulated lesion. Conclusions:The results demonstrate potential dose-depth improvements with kV arc therapy by distributing the surface flux with a wide converging beam along with perpendicular mechanical source rotation of the LCRS. The system delivered tolerable dose to a large surface area when a threshold of multiple,

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“…Proof-of-principle simulations were first used with a transmission anode design. These simulations for cylindrical water phantoms indicated that a skin sparing effect could be produced while delivering a dose rate up to 345 cGy/min for a 1-cm diameter spherical target, with dose rates decreasing at greater target size and depth [51].…”

Section: Kilovoltage X-ray Beam Arc Therapymentioning

confidence: 99%

External beam radiation therapy with kilovoltage x-rays

Breitkreutz

M²,

Bazalova‐Carter

2020

Physica Medica

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Kilovoltage (kV) x-rays are most commonly used for diagnostic imaging due to their sensitivity to tissue composition. In radiation therapy (RT), due to their fast attenuation, kV x-rays are typically only used for superficial irradiation of skin cancer and for intra-operative RT (IORT). Recently, however, a number of kV RT techniques have emerged. In this review article, we provide a brief overview of the use of kV x-rays for RT. Various kV x-ray source technologies suitable for RT, such as conventional x-ray tubes as well as novel x-ray sources, are first described. This x-ray source section is then followed by a section on their implementation in terms of clinical, veterinary and preclinical applications. Specifically, IORT, superficial RT and dose enhancement with iodine and gold nanoparticles, as well as microbeam RT and FLASH RT are discussed in this context. Then, a number of kV x-ray RT applications in modeling and proof-of-principle stages, such as breast external beam RT with rotational sources, kilovoltage arc therapy and the BriXS Compton pulsed x-ray sources, are reviewed. Finally, some clinical and economic considerations for the development of kV RT techniques are discussed.

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Monte Carlo simulations of a kilovoltage external beam radiotherapy system on phantoms and breast patients

Abstract: Although nonoptimized KVAT dose distributions presented here were of inferior quality to VMAT plans, this work has demonstrated the feasibility of delivering low-energy kilovoltage x-rays to lesions up to 4 cm in diameter to depths of 8.1 cm while sparing surrounding tissue.

Cited by 14 publications

References 18 publications

Inverse optimization of low‐cost kilovoltage x‐ray arc therapy plans

Inverse optimization of low‐cost kilovoltage x‐ray arc therapy plans

Dosimetry of a novel converging X‐ray source for kilovoltage radiotherapy

External beam radiation therapy with kilovoltage x-rays

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