Estimation of patient organ doses from CT examinations in Tanzania

Abstract

Although the use of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures, lack of optimized protocols could be an additional source of increased dose in developing countries. The aims of this study are, first, to determine the magnitude of radiation doses received by selected radiosensitive organs of patients undergoing CT examinations and compare them with other studies, and second, to assess how CT scanning protocols in practice affect patient organ doses. In order to achieve these objectives, patient organ doses from five common CT examinations were obtained from eight hospitals in Tanzania. The patient organ doses were estimated using measurements of CT dose indexes (CTDI), exposure‐related parameters, and the ImPACT spreadsheet based on NRPB conversion factors. A large variation of mean organ doses among hospitals was observed for similar CT examinations. These variations largely originated from different CT scanning protocols used in different hospitals and scanner type. The mean organ doses in this study for the eye lens (for head), thyroid (for chest), breast (for chest), stomach (for abdomen), and ovary (for pelvis) were 63.9 mGy, 12.3 mGy, 26.1 mGy, 35.6 mGy, and 24.0 mGy, respectively. These values were mostly comparable to and slightly higher than the values of organ doses reported from the literature for the United Kingdom, Japan, Germany, Norway, and the Netherlands. It was concluded that patient organ doses could be substantially minimized through careful selection of scanning parameters based on clinical indications of study, patient size, and body region being examined. Additional dose reduction to superficial organs would require the use of shielding materials.PACS numbers: 87.59 Fm; 87.66Jj; 87.52‐g

Computed Tomography Organ dose determination using ImPACT simulation software: Our findings in South-West Nigeria

“…Ngaile's dose range to the brain was 32.5-84.4mGy which was higher than those obtained in our study which was 15-44.7mGy. [36] Also, Organ dose to the lungs, breast, thyroid and heart in this study among the 7 CT units also showed similar differences in dose value with lungs (p<0.001), breast (p<0.001), thyroid (p=0.008), heart (p<0.001), further proving statistically significant differences in protocol used by each CT unit among the hospitals. The dose range to the lung in this study was 15.3-41.7mGy, with an average dose of 30.63mGy.…”

Assessment of Organ Dose by Direct and Indirect Measurements for a Wide Bore X-Ray Computed Tomography Unit That Used in Radiotherapy

“…The summary of whole process that involved in this study is shown as a flow chart at As a general in the literature, the CTDI 100 air value for conventional CT scanner is reported to be from 17 to 48 mGy [6] [47]. For this dedicated CT scanner, the CTDI 100 values were in the range of values from conventional CT.…”

“…Patient doses from CT procedures are relatively higher than doses from other imaging modalities based on ionizing radiation [3]- [6]. From the data published in 2006, the use of CT has increased at a rate of 8% -15% per year for the last 7 -10 years at United States [7].…”

Assessment of knowledge and awareness among radiology personnel regarding current computed tomography technology and radiation dose

“…Many researchers have highlighted issues regarding choice of CT parameters and the influence on the dose to patients, the discussions narrowing down on how to optimize the dose [7][8][9][10], noting that there are many possible combinations of choice to optimize CT parameters. Radiology personnel and other users need to be knowledgeable about the various means in controlling radiation output of CT parameters via used tube potential, tube current, slice thickness, pitch, the detector used and etc.…”