Determine Cumulative Radiation Dose and Lifetime Cancer Risk in Marfan Syndrome Patients Who Underwent Computed Tomography Angiography of the Aorta in Northeast Thailand: A 5-Year Retrospective Cohort Study

Objective: To evaluate computed tomography angiography (CTA) data focusing on radiation dose parameters in Thais with Marfan syndrome (MFS) and estimate the distribution of cumulative radiation exposure from CTA surveillance and the risk of cancers. Methods: Between 1st January 2015 and 31st December 2020, we retrospectively evaluated the cumulative CTA radiation doses of MFS patients who underwent CTA at Khon Kaen University Hospital, a leading teaching hospital and advanced tertiary care institution in northeastern Thailand. We utilized the Radiation Risk Assessment Tool (RadRAT) established at the National Cancer Institute in Bethesda, Maryland, to evaluate the risk of cancer-related CTA radiation. Results: The study recruited 29 adult MFS patients who had CTA of the aorta during a 5-year study period with 89 CTA studies. The mean cumulative CTDI vol is 21.5 ± 14.68 mGy, mean cumulative DLP is 682.2 ± 466.7 mGy.cm, the mean baseline future risk for all cancer is 26,134 ± 7601 per 100,000, and the excess lifetime risk for all cancer is 2080.3 ± 1330 per 100,000. The excess lifetime risk of radiation-induced cancer associated with the CTA surveillance study is significantly lower than the risk of aortic dissection or rupture and lower than the baseline future cancer risk. Conclusions: We attempted to quantify the radiation-induced cancer risk from CTA surveillance imaging performed for MFS patients in this study, with all patients receiving a low-risk cumulative radiation dose (less than 1 Gy) and all patients having a low excessive lifetime risk of cancer as a result of CTA. The risk–benefit decision must be made at the point of care, and it entails balancing the benefits of surveillance imaging in anticipating rupture and providing practical, safe treatment, therefore avoiding morbidity and mortality.

An Investigation of Exposure to the Eyes and Thyroid of Personnel Near to Patient in Abdominal Radiography: A Phantom Study

Abdominal radiography is beneficial in a variety of clinical situations. Prior to the introduction of multiplanar imaging, it was considered as the main examination for gastrointestinal pathology. However, the radiation dose received is considered high since it is equivalent to the dose of at least 75 chest radiographs. Personnel including staff or relatives may be required to assist patients in many conditions, increasing unnecessary radiation and the likelihood of radiation-induced cancer. The purpose of this study was to determine the radiation dose received by personnel when eyes and thyroid are exposed during abdominal radiography. The Rando and body phantoms were used to represent personnel and patients in this experimental approach. The dose was measured as entrance surface dose (ESD) by using TLD-100, which was positioned at the Rando phantom's eyes and thyroid. The study included a total of twenty exposures, five times at each of four distinct sites. The mean doses (eyes/thyroid in mGy) were (0.083/0.081), (0.090/0.087), (0.093/0.092), and (0.092/0.089), respectively, at locations 1, 2, 3, and 4. The results indicated that there was no correlation between organ and location affecting ESD measurement (p=0.960). There was no significant difference in dose between the two organs (p=0.355), with the mean difference in the eyes being 0.002 more than in the thyroid. The proximity of the eyes to the tube source contributed for the increased dose observed at the eyes. Though ESD was substantial for location pairings 1 vs. 3 (p=0.001) and 1 vs. 4 (p=0.015) owing to the anode-cathode phenomena. In conclusion, personnel should avoid the tube source and cathode region, since they give a greater dose of radiation, particularly when the personnel are closest to the patient and does not have eyes or thyroid protection.

Distortion of the radiation background of the urban environment due to the aggressive influence of the technosphere. Stage 2: parks and recreation areas

В работе представлены результаты исследования гамма-фона от объектов техносферы в городской среде г. Томска, Россия, с помощью высокочувствительных детекторов БДКГ-03. Было замечено, что в радиусе 1 м от некоторых объектов техносферы поглощенная доза была на 1.5–4.4 выше, чем предел дозы, рекомендованный НКДАР ООН. Максимальная зарегистрированная мощность дозы на расстоянии 50 см от объектов техносферы составила 0.204 мкЗв/ч, что соответствует среднегодовой эффективной дозе внешнего облучения 0.31 мЗв и риску радиационно-индуцированного рака в течение жизни 1.09·10-3. Диапазон изменения мощности амбиентного эквивалента дозы гамма-излучения в г. Томске составил от 0.058 мкЗв/ч до 0.39 мкЗв/ч. The paper presents the results of a study of the gamma background from technosphere objects in the urban environment of Tomsk, Russia, using high-sensitivity detectors BDKG-03. It was noted that within a radius of 1 m from some objects of the technosphere, theabsorbed dose was 1.5–4.4 higher than the dose limit recommended by UNSCEAR. The maximum recorded dose rate at a distance of 50 cm from the objects of the technosphere was 0.204 mSv/h, which corresponds to an average annual effective dose of external radiation of 0.31 mSv and a lifetime risk of radiation-induced cancer of 1.09 ·10-3. The variation range of the ambient dose equivalent rate of gamma radiation in Tomsk was from 0.058 mSv/h to 0.39 mSv/h.

Relationship of the Mean Glandular Dose with Compressed Breast Thickness in Digital Mammography

Introduction: Mammography is one of the most commonly performed radiological investigations for evaluation of breast cancer. As it involves ionizing radiation, there remains a risk of radiation induced cancer. In this study, we evaluated compressed breast thickness (CBT) and mean glandular dose (MGD) during routine mammography. Methods: This prospective study was performed in the Department of Radiology and Imaging of TUTH. Data of 500 consecutive patients who underwent mammography over a period of 4 months (June 2018 to September 2018) was collected. The age, CBT and MGD were recorded. Pearson correlation and paired-t tests were performed. Results: Most of the patients belonged to 41-50 years age group. MGD was significantly higher in patients with increased CBT. The CBT and MGD was higher in MLO view compared to CC views. The mean value of total MGD for four views was 5.1±1.4 mGy. There was significant positive correlation (r= 0.517) between CBT and MGD with increase in MGD with increase in CBT. Conclusions: The MGD and dose equivalent in our routine mammography is within the recommended limits. MGD increases with increasing CBT and vice-versa. Hence, decreasing the thickness of compressed breast, can decrease the amount of radiation absorbed by the glandular tissue of the breast.