Cancerogenesis Risks between 64 and 320 Row Detector CT for Coronary CTA Screening

Objectives: This study compares cancerogenesis risks posed by the 64 row detector and the 320 row detector computed tomography scanners used during coronary computed tomography angiography (CCTA) following decennial screening guidelines. Material and Methods: Data of the radiation absorbed after CCTA by lung, thyroid, and female breast in patients between 50 and 70 years of age obtained from prior published literature for the 64 row CT scanner were compared with data from our study using 320 row detector CT scanner. Data from the 64 row and the 320 row detector CT scanners was used to determine lifetime attributable risks (LAR) of cancer based on the biological effects of ionizing radiation (BEIR) VII report. Results: The relative reduction of LAR (%) for 50-, 60-, and 70-year-old patients undergoing scanning with the 320 row detector CT scanner was 30% lower for lung, and more than 50% lower for female breast when compared with results from 64 row detector CT scanner. The use of 320 row detector CT would result in a combined cumulative cancer incidence of less than 1/500 for breast in women and less than 1/1000 for lung in men; By comparison, this is much lower than other more common risk factors: 16-fold for lung cancer in persistent smokers, 2-fold for breast cancer with a first degree family member history of breast cancer, and 10-fold for thyroid cancer with a family member with thyroid cancer. Decennial screening would benefit at least 355,000 patients from sudden cardiac death each year, 94% of whom have significant coronary artery disease, with at least one stenosis >75%. LAR for thyroid cancer was negligible for both scanners. Conclusion: Lung and female breast LAR reductions with 320 row detector compared with 64 row detector CT are substantial, and the benefits would outweigh increased cancer risks with decennial screening in the age group of 50-70 years.

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Thyroid Cancer Risk in Patients Undergoing 64 Slice Brain and Paranasal Sinuses Computed Tomography

Frontiers in Biomedical Technologies ◽

10.18502/fbt.v7i2.3855 ◽

2020 ◽

Author(s):

Hamid Ghaznavi

Keyword(s):

Computed Tomography ◽

Thyroid Cancer ◽

Cancer Risk ◽

Cancer Incidence ◽

Paranasal Sinuses ◽

Old Patients ◽

Thyroid Cancer Risk ◽

Paranasal Sinuses Ct ◽

Age Range ◽

Thyroid Cancer Incidence

Purpose: Computed Tomography (CT) is a fundamental part of diagnosis of diseases. During CT examinations organs in and out of scanned volume are exposed to ionization radiation. The aim of this study was Estimation Thyroid cancer risk in Patients who Underwent 64 Slice brain and paranasal sinuses CT scan. Materials and Methods: with permission from the authors and editor, data related to thyroid dose of 40 patients in Mazyar et al.'s paper was used and by using Biological Effects of Ionizing Radiation (BEIR)VII model thyroid cancer risk was calculated for different ages at exposure in male and female. Results: In both brain and paranasal sinuses CT, ERR values in female patients were twice as many as those in male patients. At age range from 20 to 40 years, ERR was considerably more than at age range 40-60 years since young patients are more radiosensitive than old patients. Conclusion: The calculations of ERR indicate that PNS and brain CT increase the theoretical risk of thyroid cancer incidence. Although the ERR values are low, impacts on the thyroid cancer incidence should not be disregarded.

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Assessment of Thyroid Cancer Risk After Cervical Computed Tomography: The Impact of Bismuth Shielding

Disease and Diagnosis ◽

10.34172/ddj.2021.14 ◽

2021 ◽

Vol 10 (2) ◽

pp. 70-74

Author(s):

Hamid Ghaznavi ◽

Zeinab Momeni ◽

Sadegh Ghaderi

Keyword(s):

Computed Tomography ◽

Thyroid Cancer ◽

Cancer Risk ◽

Biological Effects ◽

The Body ◽

Male And Female ◽

Thyroid Dose ◽

Thyroid Cancer Risk ◽

Bismuth Shielding ◽

The Impact

Background: Computed tomography (CT) is vastly applied in X-ray procedures because of its high quality in detecting the anatomical structures of the body. However, it leads to an increase in patient dose, resulting in carcinogenesis. In the head and neck CT, the thyroid is the most important at-risk organ. The aim of this study was to estimate thyroid cancer risk in cervical CT with and without a bismuth shield. Materials and Methods: After obtaining permission from the authors, data related to the thyroid dose of patients undergoing cervical CT in the study by Santos et al (2019) were used, and then thyroid cancer risk was calculated for different ages at exposure in male and female patients using the biological effects of the ionizing radiation (BEIR) VII model. Results: Using bismuth shielding reduced thyroid dose by 37% and 39% in male and female phantoms, respectively. Thyroid cancer estimation demonstrated that the risk was nearly two-fold in females compared to males. Finally, bismuth shielding reduced 40% of cancer risk, and it decreased in both genders by increasing age at exposure. Conclusion: According to our findings, excess relative risk (ERR) up to 0.06% was associated with cervical CT. Although ERR amounts were low, the effect of radiation on thyroid cancer risk should not be neglected. Accordingly, it is suggested that future trials use bismuth shielding to reduce thyroid cancer risk.

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Estimated Effective Lifetime Risks of Radiation-Induced Thyroid Cancer in Computed Tomography (CT) Brain Examination

Sains Malaysiana ◽

10.17576/jsm-2021-5011-20 ◽

2021 ◽

Vol 50 (11) ◽

pp. 3365-3372

Author(s):

Rekha Ganesan ◽

Muhammad Ikhmal Naim Mohd Hilal ◽

Iza Nurzawani Che Isa ◽

Norhashimah Norsuddin ◽

Khadijah Mohd Nassir ◽

...

Keyword(s):

Computed Tomography ◽

Thyroid Cancer ◽

Biological Effects ◽

Lifetime Risk ◽

Effective Lifetime ◽

Multiple Exposures ◽

Percentage Difference ◽

Radiation Induced ◽

Radiosensitive Organs ◽

Risk Of Cancer

Thyroid is one of the most radiosensitive organs in the human body. Although the scanning range of brain computed tomography (CT) does not include lower neck region, there is possibility for thyroid to be irradiated due to scattered radiation because of its location near to the external beam collimation. The objective of this study was to evaluate effective lifetime risk of radiation-induced thyroid cancer in young adults following brain CT examination. A total of 306 patient data within the age range between 18 and 39 years old were retrospectively analysed. Absorbed dose of the thyroid organ was obtained through the input of data using WAZA- ARI v2. Effective lifetime risk was calculated by multiplying equivalent dose of the thyroid organ with the lifetime attributable cancer risk adapted from Biological Effects in Ionising Radiation (BEIR) Report V11. The effective lifetime risks were recorded as 0.45 ± 0.70 per 100 000 and 0.93 ± 1.52 per 100 000 for single and multiple exposures, respectively. In terms of gender, woman data (0.99 ± 0.76; 1.95 ± 2.15) were found higher as compared to man data (0.13 ± 0.39; 0.35 ± 0.45) for both single and multiple exposure. The percentage difference of effective lifetime risks between single and multiple exposures was up to 107%. The effective lifetime risk noted in this study may be low, however, the long-term risk of cancer development should be considered. This study serves as preliminary reference when revising clinical protocol especially in those involving repeated exposures in young adult patients. Future study should include other radiosensitive organs exploring the effective lifetime risk of radiation induced cancer following CT procedure.

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