Estimation of absorbed dose to thyroid in patients treated with radiotherapy for various cancers

Gul, Attia; Faaruq, Shafqat; Abbasi, Nadeem Zia; Siddique, Tariq; Ali, Akbar; Shehzadi, Nazia Neelam; Rahman, Mujeeb Ur; Khan, Amjad Aziz; Rizvi, Qaisar Abbas; Ahmad, Fayyaz

doi:10.1093/rpd/nct043

Cited by 6 publications

(6 citation statements)

References 13 publications

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“…Besides, we also analyzed the correlative relationship between the measured ESD and the simulated AD. The thyroid ESD was higher than the mean value of AD, which was consistent with the results in reference (11). The attenuation of machine leakage and low-energy scattering radiation might account for it.…”

Section: Discussionsupporting

confidence: 91%

“…However, the reported measurement procedures were usually inefficient, where 85 points could be involved for measurement. 11 The thyroid dosimetry could also be evaluated with AD simulated in treatment planning system (TPS). 2,12,13 Nevertheless, uncertainties related to beam modeling and intrafraction management might lead to inaccuracies in dose delivery, making the dose assessment inaccurate.…”

Section: Introductionmentioning

confidence: 99%

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Fast Model for Evaluation of the Thyroid Dosimetry During Chest Tumor Radiotherapy

Wang

Zheng

et al. 2019

Dose-Response

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Due to the reported high incidence of thyroid cancer induced by radiotherapy, dose assessment is significant to prevent thyroid late effects. Thyroid dosimetry can be evaluated either by entrance skin dose (ESD) measured with thermoluminescent dosimeter (TLD) arrays or by absorbed dose (AD) computed with treatment planning system. However, their correlation has hardly been reported in any publications. Moreover, the reported measurement procedures for thyroid ESD are usually inefficient. This study aims to provide a fast model for efficient acquisition of thyroid ESD and analyze the coherent relationship between ESD and AD. We conducted the study on the China radiation anthropomorphic phantom with intentionally delineated cancers, irradiated by a Varian 23EX linac. We have measured the ESD with TLD at 5 different points, while computed AD with the Oncentra Masterplan TPS. The ESD at the middle gorge of thyroid has exhibited significant linear correlation with those measured at other points. Furthermore, a regressive model has been proposed to predict thyroid AD from ESD. Consequently, it is recommended to only measure the ESD at the middle gorge of thyroid for an efficient dose assessment. The validity of the regressive model to predict thyroid AD from ESD has also been demonstrated.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Fast Model for Evaluation of the Thyroid Dosimetry During Chest Tumor Radiotherapy

Wang

Zheng

et al. 2019

Dose-Response

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“…However, the number of exposed cases, particularly exposed cases with doses of 30 Gy or more, was basically too small to fit more complex models. It is difficult to compare given doses to absorbed doses; however, as an example, for Hodgkin Lymphoma patients Gul et al [ 7 ] estimate that 64-94 % of the given dose is also absorbed by the thyroid.…”

Section: Discussionmentioning

confidence: 99%

“…Besides leukaemia and breast cancer, thyroid cancer is most frequently associated with radiation exposure [ 2 ]. Gul et al [ 7 ] identified high doses absorbed by the thyroid gland due to scattered radiation during radiotherapy for breast cancer, lung cancer, Hodgkin’s lymphoma and tumours in the head and neck region using CO 60 teletherapy. An association between the occurrence of thyroid adenomas and the radiation dose received during childhood cancer treatment has been recently shown [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Radiotherapy and subsequent thyroid cancer in German childhood cancer survivors: a nested case–control study

et al. 2015

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BackgroundRadiotherapy is associated with a risk of subsequent neoplasms (SN) in childhood cancer survivors. It has been shown that children’s thyroid glands are especially susceptible. The aim is to quantify the risk of a second neck neoplasm after primary cancer radiotherapy with emphasis on thyroid cancer.MethodsWe performed a nested case–control study: 29 individuals, diagnosed with a solid SN in the neck region, including 17 with thyroid cancer, in 1980–2002 and 57 matched controls with single neoplasms were selected from the database of the German Childhood Cancer Registry. We investigated the risk associated with radiotherapy exposure given per body region, adjusted for chemotherapy.Results16/17 (94.1 %) thyroid SN cases, 9/12 (75 %) other neck SN cases and 34/57 (59.6 %) controls received radiotherapy, with median doses of 27.8, 25 and 24 Gy, respectively. Radiotherapy exposure to the neck region increased the risk of the other neck SNs by 4.2 % (OR = 1.042/Gy (95 %-CI 0.980-1.109)) and of thyroid SN by 5.1 % (OR = 1.051/Gy (95 %-CI 0.984-1.123)), and radiotherapy to the neck or spine region increased the thyroid risk by 6.6 % (OR = 1.066/Gy (95 %-CI 1.010-1.125)). Chemotherapy was not a confounder. Exposure to other body regions was not associated with increased risk.ConclusionsRadiotherapy in the neck or spine region increases the risk of thyroid cancer, while neck exposure increases the risk of any other solid SN to a similar extent. Other studies showed a decreasing risk of subsequent thyroid cancer for very high doses; we cannot confirm this.

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“…[8] Several studies have shown that women with breast cancer have an additional risk for other cancers such as thyroid cancer. [121314] Many studies evaluated the risk of secondary cancer in radiotherapy of breast cancer patients and also a great variety can be seen in their methodology (measurement[15] or calculation[16]), dosimetry mediums (phantom[1718] or patient[19]), dosimeters (thermoluminescent dosimeter [TLD], metal-oxide-semiconductor field-effect transistor or other types),[131720] treatment techniques (standard or complex),[1718] type of treatment machines, reported quantity (medium dose, equivalent dose, and skin dose),[202122] and the risk models (International Radiation Protection Commission [ICRP] or biological effects of ionizing radiation [BEIR]). [1823]…”

Section: Introductionmentioning

confidence: 99%

Estimation of the thyroid secondary cancer risk on the patient of standard breast external beam radiotherapy

2018

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Background:The purpose of this study was to estimate the secondary cancer risk of thyroid in standard radiotherapy methods which are commonly used for breast cancer patients.Methods:A total of 64 breast cancer patients (their age range was around 50 years old) who referred to Seyed-Al-Shohada hospital (Isfahan, Iran) were included in this study. The radiotherapy of the mentioned patients was performed using 6-MV photon beams. Dose measurements were also done using thermoluminescent dosimeters. Calculation of the risk of developing secondary cancer in thyroid was done using the Biological Effects of Ionizing Radiation Committee VII and recommended quantity of the International Radiation Protection Commission, excess relative risk.Results:The mean radiation dose to thyroid for the tangential beams, tangential field with supraclavicular (SC) field, and also a tangential field with SC field in modified radical mastectomy (MRM) were 0.883 ± 0.472, 1.512 ± 0.365, and 1.587 ± 0.37, respectively. The risk of developing secondary thyroid cancer over a period of 5 years after breast cancer therapy in the tangential, tangential with a SC field, and also tangential beam with SC field in MRM were 9.974 ± 4.318, 17.891 ± 0.365, and 18.783 ± 4.384, respectively. The mean of the measured thyroid doses in patients treated with tangent fields was significantly lower than the patients under the irradiation of the tangent fields with SC field (P < 0.001).Conclusions:Using radiation protection equipment is suggested for breast cancer patients who treated with the studied radiotherapy methods.

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Estimation of absorbed dose to thyroid in patients treated with radiotherapy for various cancers

Cited by 6 publications

References 13 publications

Fast Model for Evaluation of the Thyroid Dosimetry During Chest Tumor Radiotherapy

Fast Model for Evaluation of the Thyroid Dosimetry During Chest Tumor Radiotherapy

Radiotherapy and subsequent thyroid cancer in German childhood cancer survivors: a nested case–control study

Estimation of the thyroid secondary cancer risk on the patient of standard breast external beam radiotherapy

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