Cumulative radiation exposure, effective and organ dose estimation from multiple head CT scans in stroke patients

Highlights

• Efforts should be made to dose reduction in stroke CT scans.

• CT scanning remains the useful technique for diagnosis of stroke.

• Potential risks exist from multiple CT scan.

• Referring physician awareness encourage request justification and dose optimization.

Abstract

This study aimed to estimate the cumulative radiation exposure, effective and organ dose from the recurrent computed tomography (CT) head scan during the stroke. Data was collected using a validated survey, including scanner information, patient demographic information, scan protocol, and dose indices (CTDIvol and DLP). A retrospective search of the picture archiving and communicating system (PACS) database for all the patients who underwent at least three head scans while admitted to the hospital because of stroke. Effective and organ doses are calculated by VirtualDose software based on ICRP 103. One hundred fifty-two patients underwent three to five scans during their hospitalization, which lasted from three weeks to three months. The age ranged from 45-to 76 years; males were (n = 104, 68.4%) and females were (n = 48, 35.6%). The scan range was 20.9–28.8 cm, with a mean of 24.4 ± 1.5. The mean CTDIvol and DLP values per scan were 21 ± 0.8 and 429 ± 85, respectively. The calculated effective doses for patients with three, four, and five scans were 6.4, 8.5, and 10.7 mSv, respectively. The highest organ dose is recorded in the brain and the lowest at the breast. Focusing on referring physician awareness and encouraging request justification and dose optimization for patients subject to frequent radiation exams. In addition, the cumulative effective dose should be part of training programs for referrers, radiologists and radiographers.

Introduction

Computed tomography (CT) has changed the way doctors practice medicine since its emergence in 1971. Many patients benefit from it since it provides faster and more reliable diagnostic information less invasively than before (Liguori et al., 2015). CT is used for diagnostic purposes and therapeutic applications, including proton therapy and brachytherapy for precise treatment planning and optimization of radiotherapy using dual-energy CT (DECT) or spectral CT technology (Kruis, 2022; Van Elmpt et al., 2016). The growing number of exams done using this technology and the introduction of novel procedures performed under CT guidance in clinical practice have improved the role of CT in medicine and encouraged new clinical applications (Van Elmpt et al., 2016). However, ionizing radiation, which may trigger second malignancies, is a downside of CT. The number of CT scans performed increased significantly in recent years. Improvements in CT technology, the broad availability of CT, and patient and physician-generated demand. Importantly, some patients are subjected to multiple CT scans (Kwee et al., 2020). The repeated and multiple scans are considered problematic due to the cumulative dose and potential risk from ionizing radiation. Previous studies showed that CT radiation dosages vary significantly among patients, hospitals, and countries up to 17-folds (Smith-Bindman et al., 2019; Sulieman et al., 2020). Ionizing radiation is a proven carcinogen, and CT radiation has been linked to increased cancer risk. As a result, it's critical to decrease excessive variance in examination techniques and minimize exposure to medical imaging (Jaafar et al., 2021; Smith-Bindman et al., 2019).

Stroke is considered the major frequent cause of morbidity and mortality neurological disease and represents 11·6% of total deaths worldwide (Feigin, 2021). Stroke ranks first in frequency and important among all the neurological diseases of adult life. It is the third leading cause of death worldwide (Feigin, 2021). Neuroimaging is the foundation for guiding acute stroke patients by supplying the information needed to correctly triage patients, expedite clinical decision-making regarding treatment, and improve outcomes in patients presenting with acute stroke. It is critical to make an accurate and timely diagnosis. CT allows for time-critical decision-making in stroke patients, informing treatment and follow-up.

Multiple CT scan procedures are not unique for stroke patients. Patients with stroke receive multiple diagnostics scans during admission and are thus at risk from the cumulative radiation dose (CED). Previous studies reported in a multi-institutional study that 1.33%–2.72% of patients (20% ≤ 50 years old) received a cumulative effective dose of ≥100.0 mSv with an overall median and maximum value of 130.3 mSv and 1185 mSv, respectively (Rehani and Madan, 2020). The CED radiation exposure to young patients is high enough to cause serious side effects by increasing the probability of cancer incidence in the future (Rehani and Madan, 2020). Various studies reported that a high cumulative radiation dose could increase cancer risk (Griffey and Sodickson, 2009; Kim, 2004; Kritsaneepaiboon et al., 2018). Even though the minimum risk is expected, it should be weighted by the medical benefits. Proper procedural justification and dosage optimization are critical to quantifying the lifetime attributable risk of radiation-induced cancer. After the patient stabilized and during the rehabilitation phase, the debate between procedure rationale and patient life was decreased for stroke patients since non-ionizing radiation procedures could be requested. This study aimed to determine the effective dose and organ dose from several head scans in a short period. This study aimed to estimate cumulative radiation exposure, effective and organ dose of adult stroke patients undergoing multiple head CT scans.