Verification of absorbed dose using diodes in cobalt-60 radiation therapy

Gadhi, Muhammad Asghar; Fatmi, Shahab; Chughtai, Gul M.; Arshad, Muhammad Sajid; Shakil, M.; Rahmani, Uzma Mahmood; Imran, Malik Younas; Buzdar, Saeed Ahmad

doi:10.1007/s13246-016-0422-5

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…Traditionally, TLDs and diodes have been the choice for use as an in vivo dosimeter due to their high accuracy in entrance dose determinations [76][77][78][79][80][81]. Evwierhurhoma, Ibitoye [76] determined the role of TLDs during in vivo dosimetry.…”

Section: Entrance Dose Assessmentmentioning

confidence: 99%

“…They showed that no significant difference existed between the prescribed dose and measured dose of the breast with a percentage deviation difference of less than 5%. Gadhi, Fatmi [81] developed an absorbed dose verification program using the diode in vivo dosimetry system for entrance dose measurements. Phantom studies carried out in their work showed that the percentage difference between measured and calculated dose for entrance setting remained within ±2%.…”

Section: Entrance Dose Assessmentmentioning

confidence: 99%

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Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine

et al. 2022

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Purpose In vivo dosimetry is a quality assurance tool that provides post-treatment measurement of the absorbed dose as delivered to the patient. This dosimetry compares the prescribed and measured dose delivered to the target volume. In this study, a tissue-equivalent water phantom provided the simulation of the human environment. The skin and entrance doses were measured using GafChromic EBT2 film for a Theratron® Equinox Cobalt-60 teletherapy machine. Methods We examined the behaviors of unencapsulated films and custom-made film encapsulation. Films were cut to 1 cm × 1 cm, calibrated, and used to assess skin dose depositions and entrance dose. We examined the response of the film for variations in field size, source to skin distance (SSD), gantry angle and wedge angle. Results The estimated uncertainty in EBT2 film for absorbed dose measurement in phantom was ±1.72%. Comparison of the measurements of the two film configurations for the various irradiation parameters were field size (p = 0.0193, α = 0.05, n = 11), gantry angle (p = 0.0018, α = 0.05, n = 24), SSD (p = 0.1802, α = 0.05, n = 11) and wedge angle (p = 0.6834, α = 0.05, n = 4). For a prescribed dose of 200 cGy and at reference conditions (open field 10 cm x 10 cm, SSD = 100 cm, and gantry angle = 0º), the measured skin dose using the encapsulation material was 70% while that measured with the unencapsulated film was 24%. At reference irradiation conditions, the measured skin dose using the unencapsulated film was higher for open field configurations (24%) than wedged field configurations (19%). Estimation of the entrance dose using the unencapsulated film was within 3% of the prescribed dose. Conclusions GafChromic EBT2 film measurements were significantly affected at larger field sizes and gantry angles. Furthermore, we determined a high accuracy in entrance dose estimations using the film.

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Section: Entrance Dose Assessmentmentioning

confidence: 99%

Section: Entrance Dose Assessmentmentioning

confidence: 99%

Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine

et al. 2022

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Deviation Between the Planned Dose and the in Vivo Dosimetry Results During Postoperative Irradiation in Patients With Uterine Cancer Depending on Anthropometric Data

Сухіна¹,

Sіmbіrova²,

Sukhin³

2021

Probl Radiac Med Radiobiol

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Topometry is an integral part of irradiation whose task is to repeat the position of the patient set by the simulator to repeat the PTV and the spatial relationship between the radiation field and the risk organs that were identified during planning. The dose distribution formulated in the plan is only an ideal model. There is some gap between the actual and planned dose distribution, especially in overweight patients. Objective: evaluate the effect of anthropometric data on the deviation between the planned dose and the results of dosimetry in vivo in patients with uterine cancer during postoperative irradiation. Materials and Methods. The authors analyzed the results of treatment of 110 patients with stage IB–II uterine cancer who were treated at the Department of Radiation Therapy of the Institute of Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine from 2016 to 2019. The technique of classical fractionation was used with a single focal dose of 2.0 Gy 5 times a week, the total focal dose was 42.0–50.0 Gy. To assess the effect of the patient’s anthropometric data on the difference between the actual and calculated dose, the authors performed in vivo dosimetry after the first session and in the middle of the postoperative course of external beam radiation therapy. Results. Рatients with BSA < 1.92 m2, had the median relative deviation at the first session -4.12 %, after 20.0 Gy – 3.61 %, patients with BSA > 1.92 m2: -2.06 % and -1.55 % respectively. After 20 Gy 34.8 % of patients with BSA < 1.92 m2 there was an increase in deviation from the planned dose, 65.2 % a decrease, while in 56.1 % of patients with BSA > 1.92 m2 there was an increase, and in 43.9 % – its reduction. With increasing BMI, the actual dose received on the rectal mucosa in the tenth session of irradiation is approaching the calculated one. Conclusions. When irradiated on the ROKUS-AM device, we did not find a probable dependence of the influence of the constitutional features of patients between the received and planned radiation dose. When treated with a Clinac 600 C, only body weight and body mass index at the tenth irradiation session have a likely effect on the dose difference. Therefore, issues related to the individual approach to the treatment of uterine cancer, depending on anthropometric data is an urgent problem of modern radiotherapy. Key words: anthropometric data, obesity, radiation therapy, preradiation preparation, in vivo dosimetry, uterine cancer.

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Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

Ndonye¹,

Tagoe²

2022

IJMPCERO

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Verification of absorbed dose using diodes in cobalt-60 radiation therapy

Cited by 3 publications

References 10 publications

Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine

Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine

Deviation Between the Planned Dose and the in Vivo Dosimetry Results During Postoperative Irradiation in Patients With Uterine Cancer Depending on Anthropometric Data

Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

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