A practical approach to diode based in vivo dosimetry for intensity modulated radiotherapy

Kadesjö, Nils; Nyholm, Tufve; Olofsson, Jörgen

doi:10.1016/j.radonc.2010.12.018

Cited by 16 publications

(12 citation statements)

References 16 publications

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“…In addition, TLDs require repeat calibration due to variation in sensitivity due to progressive use. Semiconductor diodes [11] have some advantages over TLD for in vivo dosimetry, namely, immediate readout and reproducibility. However, diodes [1112] have certain disadvantages such as energy, dose rate, and angular dependent response.…”

Section: Introductionmentioning

confidence: 99%

“…Semiconductor diodes [11] have some advantages over TLD for in vivo dosimetry, namely, immediate readout and reproducibility. However, diodes [1112] have certain disadvantages such as energy, dose rate, and angular dependent response. In addition, diodes need to be connected to the reader system during measurement by running a long cable from the treatment room to the measurement station.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

Kumar¹,

Sharma²,

Ravindran³

2014

J Med Phys

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The characteristics of a mobile metal oxide semiconductor field effect transistor (mobile MOSFET) detector for standard bias were investigated for megavoltage photon beams. This study was performed with a brass alloy build-up cap for three energies namely Co-60, 6 and 15 MV photon beams. The MOSFETs were calibrated and the performance characteristics were analyzed with respect to dose rate dependence, energy dependence, field size dependence, linearity, build-up factor, and angular dependence for all the three energies. A linear dose-response curve was noted for Co-60, 6 MV, and 15 MV photons. The calibration factors were found to be 1.03, 1, and 0.79 cGy/mV for Co-60, 6 MV, and 15 MV photon energies, respectively. The calibration graph has been obtained to the dose up to 600 cGy, and the dose-response curve was found to be linear. The MOSFETs were found to be energy independent both for measurements performed at depth as well as on the surface with build-up. However, field size dependence was also analyzed for variable field sizes and found to be field size independent. Angular dependence was analyzed by keeping the MOSFET dosimeter in parallel and perpendicular orientation to the angle of incidence of the radiation with and without build-up on the surface of the phantom. The maximum variation for the three energies was found to be within ± 2% for the gantry angles 90° and 270°, the deviations without the build-up for the same gantry angles were found to be 6%, 25%, and 60%, respectively. The MOSFET response was found to be independent of dose rate for all three energies. The dosimetric characteristics of the MOSFET detector make it a suitable in vivo dosimeter for megavoltage photon beams.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

Kumar¹,

Sharma²,

Ravindran³

2014

J Med Phys

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“…A dosimetria in vivo é a última etapa a ser seguida no controle de qualidade em tratamentos radioterápicos permitindo checar a dose em órgãos críticos ou em geometrias nas quais é difícil prever a dose diretamente do planejamento [37]. Este método permite comparar a dose prescrita com a dose recebida pelo paciente durante o tratamento, assegurando, assim, um nível de qualidade que complementa portal filme e modelos computacionais [38].…”

Section: As Medidas De Controle De Qualidade Em Aceleradores Linearesunclassified

“…A dose de saída ajuda a determinar a influência da forma, tamanho e variações de densidade do paciente no procedimento de cálculo da dose. Quando introduzidos em cavidades do corpo do paciente tais como, esôfago, reto, vagina e bexiga, os detectores de dosimetria in vivo permitem medir diretamente a dose recebida na parte interna do paciente [37,39].…”

Section: As Medidas De Controle De Qualidade Em Aceleradores Linearesunclassified

“…Quando utilizada para este fim é imprescindível se considerar os possíveis efeitos prejudiciais que a radiação pode ocasionar -doses 5% inferiores à prescrita podem diminuir em 15% a probabilidade de controle do tumor e 5% superior pode, para algumas estruturas normais, ocasionar efeitos secundários -se a dose entregue ao paciente não for determinada de maneira exata e rigorosa [5]. Por isso existe um programa de controle de qualidade que tem como objetivo observar alterações no sistema radioterápico e reduzir o impacto de qualquer um desses fatores [6].…”

Section: Introductionunclassified

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Caracterização das propriedades dosimétricas de diodos de silício empregados em radioterapia com feixe de fótons

Bizetto¹

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Evaluation of the effects of implementing a diode transmission device into the clinical workflow

et al. 2020

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This work investigated effects of implementing the Delta 4 Discover diode transmission detector into the clinical workflow. Methods: PDD and profile scans were completed with and without the Discover for a number of photon beam energies. Transmission factors were determined for all beam energies and included in Eclipse TPS to account for the attenuation of the Discover. A variety of IMRT plans were delivered to a Delta 4 Phantom+ with and without the Discover to evaluate the Discover's effects on IMRT QA. An imaging QA phantom was used to assess the detector's effects on MV image quality. OSLDs placed on the Phantom+ were used to determine the detector's effects on superficial dose. Results: The largest effect on PDDs after d max was 0.5%. The largest change in beam profile symmetry and flatness was 0.2% and 0.1%, respectively. An average difference in gamma passing rates (2%/2 mm) of 0.2% was observed between plans that did not include the Discover in the measurement and calculation to plans that did include the Discover in the measurement and calculation. The Discover did not significantly change the MV image quality, and the largest observed increase in the relative superficial dose when the Discover was present was 1%. Conclusions:The effects the Discover has on the linac beam were found to be minimal. The device can be implemented into the clinic without the need to alter the TPS beam modeling, other than accounting for the device's attenuation. However, a careful workflow review to implement the Discover should be completed.

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A practical approach to diode based in vivo dosimetry for intensity modulated radiotherapy

Cited by 16 publications

References 16 publications

Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

Caracterização das propriedades dosimétricas de diodos de silício empregados em radioterapia com feixe de fótons

Evaluation of the effects of implementing a diode transmission device into the clinical workflow

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