Energy and angular anisotropy optimisation of a p-type diode for in vivo dosimetry in photon-beam radiotherapy

Greene, Simon; Price, Robert A.

doi:10.1093/rpd/nci021

Cited by 6 publications

(8 citation statements)

References 9 publications

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“…After irradiation, the readings of the diodes were read online. Measured entrance dose and exit doses by the diode were calculated, using the following equations (6,19,20,(26)(27)(28) are the exit dose correction factors for SSD, field size, and angle of radiation, respectively.…”

Section: Entrance and Exit Dose Measurementmentioning

confidence: 99%

Evaluation of Given Dose Accuracy in Radiation Therapy of Patient with Breast Cancer Using Diode In Vivo Dosimetry

et al. 2021

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Background: The main goal of radiation therapy is to deliver the highest dose to the tumor and at the same time the lowest dose to the surrounding normal tissue. In vivo dosimetry is a quality control procedure that, instead of controlling the components separately, directly examines the dose reached to the tumor area. Objectives: In this study, the entrance, exit, and middle dose of the breast and supraclavicular area of patients with breast cancer under radiation therapy were measured and compared with calculations. Methods: In this experimental study, the entrance and exit doses of 33 patients with breast tumors treated with 6 MV and 18MV photons were measured simultaneously. The measurement was done, using p-type diodes after calibration and, then, the midpoint dose was calculated, using the transfer method and arithmetic mean method. Also, the entrance dose, exit dose, and midline dose measured with dosimeter were compared with the calculated values in the treatment planning system. Results: There was no significant difference between calculated and measured doses in the entrance, exit, and midline point in breast regions (P > 0.05), but in the supraclavicular region, a challenge was observed. The difference in entrance and midline point between calculation and measurement is not significant based on the transfer method, but there is a significant error based on the arithmetic mean method (P < 0.05). Conclusions: In vivo dosimetry by measured real given dose to the patient can perform a basic role in the quality control of the radiotherapy department. It seems in the entrance dose, the relative error is smaller but due to the smaller value of exit dose, the relative error in small values is more apparent.

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Section: Entrance and Exit Dose Measurementmentioning

confidence: 99%

Evaluation of Given Dose Accuracy in Radiation Therapy of Patient with Breast Cancer Using Diode In Vivo Dosimetry

et al. 2021

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“…The generated charge carriers produce a pulse that can be registered by the electronic system. Silicon diode detectors coupled with an energy compensating filter are frequently used for photon active personal dosimeters [10,11].…”

Section: Jinst 9 P06023mentioning

confidence: 99%

“…where H m (10) is the personal dose-equivalent, N i is the pulse count and C i is a constant coefficient of the ith energy intervals. Using the linear combination of counts according to eq.…”

Section: Photon Transport Simulationmentioning

confidence: 99%

“…Where n is the number of photon energies which are used for irradiation and m is the number of energy intervals. The coefficients H m (10) and N i are given, and 2014 JINST 9 P06023 we are going to find the C i that physically appropriate for these equations. Different monoenergetic photons in the range of 0.3-6 MeV were used for irradiation.…”

Section: Photon Transport Simulationmentioning

confidence: 99%

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Detection and dosimetry studies on the response of silicon diodes to an²⁴¹Am-Be source

Lotfi¹,

Dizaji²,

Davani³

2014

J. Inst.

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Silicon diode detectors show potential for the development of an active personal dosimeter for neutron and photon radiation. Photons interact with the constituents of the diode detector and produce electrons. Fast neutrons interact with the constituents of the diode detector and converter, producing recoil nuclei and causing (n,α) and (n,p) reactions. These photonand neutron-induced charged particles contribute to the response of diode detectors. In this work, a silicon pin diode was used as a detector to produce pulses created by photon and neutron. A polyethylene fast neutron converter was used as a recoil proton source in front of the detector. The total registered photon and neutron efficiency and the partial contributions of the efficiency, due to interactions with the diode and converter, were calculated. The results show that the efficiency of the converter-diode is a function of the incident photon and neutron energy. The optimized thicknesses of the converter for neutron detection and neutron dosimetry were found to be 1 mm and 0.1 mm respectively. The neutron records caused by the (n,α) and (n,p) reactions were negligible. The photon records were strongly dependent upon the energy and the depletion layer of the diode. The photons and neutrons efficiency of the diode-based dosimeter was calculated by the MCNPX code, and the results were in good agreement with experimental results for photons and neutrons from an 241 Am-Be source.

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“…In recent studies on photon dosimetry, the detectors were covered by a metallic layer with an optimum thickness. The metallic cover acts as an energy compensating shield [4][5][6]. A single diode for measuring photon and neutron dose equivalent has been already published by Luszik-Bhadra [7].…”

Section: Introductionmentioning

confidence: 99%

Energy response improvement for photon dosimetry using pulse analysis

Dizaji¹

2016

Chinese Phys. C

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During the last few years, active personal dosimeters have been developed and have replaced passive personal dosimeters in some external monitoring systems, frequently using silicon diode detectors. Incident photons interact with the constituents of the diode detector and produce electrons. These photon-induced electrons deposit energy in the detector's sensitive region and contribute to the response of diode detectors. To achieve an appropriate photon dosimetry response, the detectors are usually covered by a metallic layer with an optimum thickness. The metallic cover acts as an energy compensating shield. In this paper, a software process is performed for energy compensation. Selective data sampling based on pulse height is used to determine the photon dose equivalent. This method is applied to improve the energy response in photon dosimetry. The detector design is optimized for the response function and determination of the photon dose equivalent. Photon personal dose equivalent is determined in the energy range of 0.3-6 MeV. The error values of the calculated data for this wide energy range and measured data for 133 Ba, 137 Cs, 60 Co and 241 Am-Be sources respectively are up to 20% and 15%. Fairly good agreement is seen between simulation and dose values obtained from our process and specifications from several photon sources.

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Energy and angular anisotropy optimisation of a p-type diode for in vivo dosimetry in photon-beam radiotherapy

Cited by 6 publications

References 9 publications

Evaluation of Given Dose Accuracy in Radiation Therapy of Patient with Breast Cancer Using Diode In Vivo Dosimetry

Evaluation of Given Dose Accuracy in Radiation Therapy of Patient with Breast Cancer Using Diode In Vivo Dosimetry

Detection and dosimetry studies on the response of silicon diodes to an²⁴¹Am-Be source

Energy response improvement for photon dosimetry using pulse analysis

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Energy and angular anisotropy optimisation of a p-type diode for in vivo dosimetry in photon-beam radiotherapy

Cited by 6 publications

References 9 publications

Evaluation of Given Dose Accuracy in Radiation Therapy of Patient with Breast Cancer Using Diode In Vivo Dosimetry

Evaluation of Given Dose Accuracy in Radiation Therapy of Patient with Breast Cancer Using Diode In Vivo Dosimetry

Detection and dosimetry studies on the response of silicon diodes to an241Am-Be source

Energy response improvement for photon dosimetry using pulse analysis

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Detection and dosimetry studies on the response of silicon diodes to an²⁴¹Am-Be source