Thoracic Organ Doses and Cancer Risk from Low Pitch Helical 4-Dimensional Computed Tomography Scans

Purpose. To investigate the dose depositions to organs at risk (OARs) and associated cancer risk in cancer patients scanned with 4-dimensional computed tomography (4DCT) as compared with conventional 3DCT. Methods and Materials. The radiotherapy treatment planning CT image and structure sets of 102 patients were converted to CT phantoms. The effective diameters of those patients were computed. Thoracic scan protocols in 4DCT and 3DCT were simulated and verified with a validated Monte Carlo code. The doses to OARs (heart, lungs, esophagus, trachea, spinal cord, and skin) were calculated and their correlations with patient effective diameter were investigated. The associated cancer risk was calculated using the published models in BEIR VII reports. Results. The average of mean dose to thoracic organs was in the range of 7.82-11.84 cGy per 4DCT scan and 0.64-0.85 cGy per 3DCT scan. The average dose delivered per 4DCT scan was 12.8-fold higher than that of 3DCT scan. The organ dose was linearly decreased as the function of patients’ effective diameter. The ranges of intercept and slope of the linear function were 17.17-30.95 and -0.0278--0.0576 among patients’ 4DCT scans, and 1.63-2.43 and -0.003--0.0045 among patients’ 3DCT scans. Relative risk of cancer increased (with a ratio of 15.68:1) resulting from 4DCT scans as compared to 3DCT scans. Conclusions. As compared to 3DCT, 4DCT scans deliver more organ doses, especially for pediatric patients. Substantial increase in lung cancer risk is associated with higher radiation dose from 4DCT and smaller patients’ size as well as younger age.

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Radiation Doses and Cancer Risk from CT Pulmonary Angiography Examinations

10.20944/preprints201907.0269.v2 ◽

2019 ◽

Author(s):

Hanif Haspi Harun ◽

Muhammad Khalis Abdul Karim ◽

Zulkifly Abbas ◽

Sarawana Chelwan Muniandy ◽

Akmal Sabarudin ◽

...

Keyword(s):

Computed Tomography ◽

Radiation Dose ◽

Cancer Risk ◽

Organ Dose ◽

Pulmonary Angiography ◽

Effective Diameter ◽

Radiological Protection ◽

Radiation Doses ◽

Dose Length Product ◽

The Mean

The present study aims to investigate radiation doses from Computed Tomography Pulmonary Angiography (CTPA) examinations based on the patient’s size and to estimate the probability of cancer risk induced from the examination. Data from 100 patients who had undergone CTPA examinations, such as scanning acquisition parameters, patient demography, as well as radiation dose exposure, were collected and analysed. All subjects which aged above 18 y/o were scanned using a Philips Brilliance 128 multi-detector CT (MDCT) scanner. The mean dose value for Volume Computed Tomography Dose Index (CTDIvol), Dose-Length Product (DLP) and effective dose (E) were 11.06 ± 7.17 mGy, 400.38 ± 259.10 mGy.cm and 8.68 ± 5.47 mSv respectively. In addition, with respective of patient’s effective diameter, the mean SSDE value for Group 1, Group 2 and Group 3 were 9.93 ± 3.89, 13.70 ± 9.04 and 22.29 ± 7.35, respectively. Cancer risk per million procedure was calculated based on te recommendation by the International Commission on Radiological Protection Publication 103 report. The organ dose and cancer risk attained for breast, lung and liver were 17.05 ± 10.40 mGy (194 per one million procedure), 17.55 ± 10.86 mGy (192 per one million procedure) and 15.04 ± 9.75 mGy (53 per one million procedure), respectively. In conclusion, CTDIvol underestimated, and SSDE was more accurate in describing the radiation dose. Lung and breast with larger lung effective diameter received the highest dose exposure which increase the probability of the cancer risk. Therefore, it is important to apply optimised protocols in order to reduce patient’s exposure during CTPA examination.

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Patient-Specific Radiation Dose and Cancer Risk Estimate in Computed Tomography Pulmonary Angiography Examinations Based on Lung Effective Diameter

10.20944/preprints201907.0269.v1 ◽

2019 ◽

Author(s):

Hanif Haspi Harun ◽

Muhammad Khalis Abdul Karim ◽

Zulkifly Abbas ◽

Sarawana Chelwan Muniandy ◽

Akmal Sabarudin ◽

...

Keyword(s):

Computed Tomography ◽

Radiation Dose ◽

Cancer Risk ◽

Radiation Exposure ◽

Effective Dose ◽

Organ Dose ◽

Pulmonary Angiography ◽

Effective Diameter ◽

Computed Tomography Pulmonary Angiography ◽

Radiation Dose Exposure

Computed Tomography (CT) scan examinations has greater demands especially in CT Pulmonary Angiography (CTPA) owing to the public and radiology personnel worries towards CT radiation exposure and risks. The aim of present study is to evaluate the comprehensive radiation exposure in computed tomography pulmonary angiography (CTPA) and its cancer risk. The records of 100 patients who had undergone CTPA were retrieved. The radiation dose exposure, scanning acquisition protocol as well as patient characteristics were noted. Radiation exposure were presented as Volume Computed Tomography Dose Index (CTDIvol), Size-Specific Dose Estimate (SSDE), Dose-Length Product (DLP), and effective dose (E) and organ dose. Effective cancer risk per million procedure was calculated by referring to the International Commission on Radiological Protection Publication 103. The CTDIvol, SSDE, DLP were comparable within different effective diameter groups. The average effective dose received by a patient was 8.68 mSv. The organ dose and effective cancer risk attained for breast, lung and liver were 17.05 ± 10.40 mGy (194 per one million procedure), 17.55 ± 10.86 mGy (192 per one million procedure) and 15.04 ± 9.75 mGy (53 per one million procedure), respectively. In conclusion, CTDIvol was undervalued and SSDE was more accurate in describing radiation dose exposure. The lungs and breast of subjects with large effective diameter were higher risk of developing cancer as they received the highest exposure. Therefore, extra safety measures should be considered for large-sized patients undergoing CTPA.Purpose: This study evaluates the comprehensive radiation exposure in computed tomography pulmonary angiography (CTPA) and its cancer risk.

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Organ Dose and Attributable Cancer Risk in Lung Cancer Screening with Low-Dose Computed Tomography

PLoS ONE ◽

10.1371/journal.pone.0155722 ◽

2016 ◽

Vol 11 (5) ◽

pp. e0155722 ◽

Cited By ~ 9

Author(s):

Natalia Saltybaeva ◽

Katharina Martini ◽

Thomas Frauenfelder ◽

Hatem Alkadhi

Keyword(s):

Computed Tomography ◽

Lung Cancer ◽

Cancer Screening ◽

Cancer Risk ◽

Low Dose ◽

Lung Cancer Screening ◽

Organ Dose ◽

Low Dose Computed Tomography

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Organ doses of the fetus from external environmental exposures

Radiation and Environmental Biophysics ◽

10.1007/s00411-020-00891-6 ◽

2021 ◽

Vol 60 (1) ◽

pp. 93-113

Author(s):

Nina Petoussi-Henss ◽

Daiki Satoh ◽

Helmut Schlattl ◽

Maria Zankl ◽

Vladimir Spielmann

Keyword(s):

Monte Carlo ◽

Dose Rate ◽

Organ Dose ◽

Pregnant Female ◽

Rate Coefficients ◽

Monte Carlo Code ◽

Organ Doses ◽

Organ Equivalent Dose ◽

Specific Organ ◽

External Exposures

AbstractThis article presents nuclide-specific organ dose rate coefficients for environmental external exposures due to soil contamination assumed as a planar source at a depth of 0.5 g cm−2 in the soil and submersion to contaminated air, for a pregnant female and its fetus at the 24th week of gestation. Furthermore, air kerma free-in-air coefficient rates are listed. The coefficients relate the organ equivalent dose rates (Sv s−1) to the activity concentration of environmental sources, in Bq m−2 or Bq m−3, allowing to time-integrate over a particular exposure period. The environmental radiation fields were simulated with the Monte Carlo radiation transport codes PHITS and YURI. Monoenergetic organ dose rate coefficients were calculated employing the Monte Carlo code EGSnrc simulating the photon transport in the voxel phantom of a pregnant female and fetus. Photons of initial energies of 0.015–10 MeV were considered including bremsstrahlung. By folding the monoenergetic dose coefficients with the nuclide decay data, nuclide-specific organ doses were obtained. The results of this work can be employed for estimating the doses from external exposures to pregnant women and their fetus, until more precise data are available which include coefficients obtained for phantoms at different stages of pregnancy.

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Radiation Organ Doses and Excess Lifetime Cancer Risk Due to Exposure to Gamma Radiation from Two Cement Industries in Nigeria

Journal of Scientific Research and Reports ◽

10.9734/jsrr/2019/v25i1-230178 ◽

2019 ◽

pp. 1-12

Author(s):

M. Onwuka ◽

C. P. Ononugbo ◽

G. O. Avwiri

Keyword(s):

Cancer Risk ◽

Organ Dose ◽

Cement Industry ◽

Nuclear Radiation ◽

Gis Mapping ◽

Exposure Rate ◽

Lifetime Cancer Risk ◽

Organ Doses ◽

Excess Lifetime Cancer Risk ◽

The Mean

A study of background ionizing radiation (BIR) levels to estimate organ dose rates and excess lifetime cancer risk in Unicem cement producing company, Calabar, Cross River state and Bua cement producing company, Okpella in Edo state have been carried out using Digilert 100 and Radalert-200 nuclear radiation monitor and a geographical positioning system (GPS) for GIS mapping of the area. The in-situ measurement of the exposure rate was between May, 2018 and June, 2019 at regular intervals. The average exposure rate of 0.023 mRh-1 was measured at Unicem, Calabar and 0.027 mRh-1 at Bua cement area, Okpella. The mean equivalent doses of 1.92 mSvy-1 and 2.29 mSvy-1 was recorded in Unicem and Bua Okpella respectively. The estimated mean outdoor absorbed dose rate value of 196.74 nGyh-1 in Unicem and its environment while in Bua cement industry, Okpella, the value of 234.9 nGyh-1 was obtained. The mean annual effective dose calculated was 0.24 and 0.29 mSvy-1 for Unicem and Bua Okpella respectively. The mean excess life time cancer risk recorded in the areas 0.72 x10-3 in Unicem area and 1.01 x10-3 in Bua cement environment. The calculated dose to organs showed that the testes have the highest organ dose of 0.74 mSvy-1 and 0.83 mSvy-1 for Unicem and Bua Okpella areas respectively while the liver has the lowest organ dose of 0.08 mSvy-1 and 0.11 mSvy-1 for Unicem and Bua Okpella respectively. This study revealed that the exposure rate and all the radiological risk parameters exceeded their recommended safe values. The area of study is radiologically polluted and may be detrimental to human health for long term exposure.

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ORGAN EQUIVALENT DOSE AND LIFETIME ATTRIBUTABLE RISK OF CANCER INCIDENCE AND MORTALITY ASSOCIATED WITH CARDIAC CT ANGIOGRAPHY

Radiation Protection Dosimetry ◽

10.1093/rpd/ncaa033 ◽

2020 ◽

Vol 189 (2) ◽

pp. 213-223

Author(s):

Seyed Mohammad Bagher Hosseini Nasab ◽

Mohammad Reza Deevband ◽

Ali Shabestani-Monfared ◽

Seyed Ali Hoseini Amoli ◽

Seyed Hasan Fatehi Feyzabad

Keyword(s):

Lung Cancer ◽

Cancer Risk ◽

Ct Angiography ◽

Cancer Incidence ◽

Organ Dose ◽

Attributable Risk ◽

Lifetime Attributable Risk ◽

Incidence And Mortality ◽

Males And Females ◽

Risk Of Cancer

Abstract The aim of this study is the calculation of equivalent organ dose and estimation of lifetime attributable risk (LAR) of cancer incidence and mortality related to cardiac computed tomography angiography (CCTA) because the use of CT angiography as a noninvasive diagnostic method has increased. The organ dose has been calculated by ImPACT software based on the volumetric CT dose index (CTDIvol), and LAR of cancer risk incidence and mortality from CCTA has estimated according to the BEIR VII report. The median value of the effective dose was 13.78 ± 6.88 mSv for both genders. In all scanners, the highest median value for LAR of cancer incidence in males and females for lung cancer was 44.20 and 109.17 per 100 000, respectively. And in infants was 5.89 and 12 for lung cancer in males and breast cancer in females, respectively. Also, the median value of LAR of all cancer incidence from single CCTA in adult patients for males and females was 122 and 238 cases, respectively. Maximum LAR of cancer mortality in adults for lung cancer was 40.28 and 91.84 and in pediatrics was 5.69 and 8.50 in males and females, respectively. Despite many benefits of CTA in the heart disease evaluation, according to a high radiation dose in CCTA, to reduce the cancer risk: CCTA should be used cautiously, especially for pediatric and females.

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THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY

Radiation Protection Dosimetry ◽

10.1093/rpd/ncy212 ◽

2018 ◽

Vol 185 (1) ◽

pp. 17-26 ◽

Cited By ~ 2

Author(s):

Abdulaziz A Qurashi ◽

Louise A Rainford ◽

Khalid M Alshamrani ◽

Shane J Foley

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Radiation Dose ◽

Iterative Reconstruction ◽

Organ Dose ◽

Oxide Semiconductor ◽

Obese Patients ◽

Dose Length Product ◽

Organ Doses ◽

The Impact

Abstract The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4–L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.

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A new Monte Carlo tool for organ dose estimation in computed tomography

Radioprotection ◽

10.1051/radiopro/2020006 ◽

2020 ◽

Vol 55 (2) ◽

pp. 123-134

Author(s):

C. Adrien ◽

C. Le Loirec ◽

S. Dreuil ◽

J.-M. Bordy

Keyword(s):

Computed Tomography ◽

Monte Carlo ◽

Organ Dose ◽

Technical Note ◽

Patient Specific ◽

Organ Doses ◽

Ct Dose ◽

Dose Information ◽

Ct Dose Index ◽

Mc Simulation

The constant increase of computed tomography (CT) exams and their major contribution to the collective dose led to international concerns regarding patient dose in CT imaging. Efforts were made to manage radiation dose in CT, mostly with the use of the CT dose index (CTDI). However CTDI does not give access to organ dose information, while Monte Carlo (MC) simulation can provide it if detailed information of the patient anatomy and the source are available. In this work, the X-ray source and the geometry of the GE VCT Lightspeed 64 were modelled, based both on the manufacturer technical note and some experimental data. Simulated dose values were compared with measurements performed in homogeneous conditions with a pencil chamber and then in CIRS ATOM anthropomorphic phantom using both optically stimulated luminescence dosimeters (OSLD) for point doses and XR-QA Gafchromic® films for relative dose maps. Organ doses were ultimately estimated in the ICRP 110 numerical female phantom and compared to data reported in the literature. Comparison of measured and simulated values show that our tool can be used for a patient specific and organ dose oriented radiation protection tool in CT medical imaging.

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CT DOSIMETRY FOR THE AUSTRALIAN COHORT DATA LINKAGE STUDY

Radiation Protection Dosimetry ◽

10.1093/rpd/ncaa175 ◽

2020 ◽

Vol 191 (4) ◽

pp. 423-438

Author(s):

Zoe Brady ◽

Anna Forsythe ◽

Jasmine McBain-Miller ◽

Katrina J Scurrah ◽

Nicolas Smoll ◽

...

Keyword(s):

Organ Dose ◽

Linkage Study ◽

Ct Scans ◽

Organ Doses ◽

Technical Parameters ◽

Excess Cancer Risk ◽

Increased Risk ◽

Australian Cohort ◽

Technological Improvements ◽

Risk Of Cancer

Abstract Children undergoing computed tomography (CT) scans have an increased risk of cancer in subsequent years, but it is unclear how much of the excess risk is due to reverse causation bias or confounding, rather than to causal effects of ionising radiation. An examination of the relationship between excess cancer risk and organ dose can help to resolve these uncertainties. Accordingly, we have estimated doses to 33 different organs arising from over 900 000 CT scans between 1985 and 2005 in our previously described cohort of almost 12 million Australians aged 0–19 years. We used a multi-tiered approach, starting with Medicare billing details for government-funded scans. We reconstructed technical parameters from national surveys, clinical protocols, regulator databases and peer-reviewed literature to estimate almost 28 000 000 individual organ doses. Doses were age-dependent and tended to decrease over time due to technological improvements and optimisation.

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Cancer Risk Assessment of Patients Undergoing Computed Tomography Examination at the Korle-Bu Teaching Hospital

International Journal of Scientific Research in Science and Technology ◽

10.32628/ijsrst184170 ◽

2018 ◽

pp. 861-868

Author(s):

T. A. Sackey ◽

C. Schandorf ◽

J. J. Fletcher ◽

Y. B. Mensah ◽

I. Shirazu ◽

...

Keyword(s):

Computed Tomography ◽

Cancer Risk ◽

Effective Dose ◽

Teaching Hospital ◽

Cancer Incidence ◽

Attributable Risk ◽

Cancer Risk Assessment ◽

Dose Length Product ◽

Effective Doses ◽

Risk Of Cancer

The aim of this study is to estimate the effective dose and assess the lifetime attributable risk of cancer incidence of patients undergoing computed tomography scan at the Korle-Bu Teaching Hospital in the Greater Accra Region of Ghana. Data on Volume CT Dose Index ( ) and Dose Length Product ( ) displayed on the scanner control console was recorded after confirmation of the results by performing independent checks on a phantom. The effective doses were estimated using the displayed and the anatomic region specific conversion factors ( ). The average effective dose for the head, abdomen, chest, neck, and pelvis were 3.63± 2.39mSv, 15.37±8.49 mSv, 12.72 ± 13.97 mSv, 4.04 ± 1.47 mSv and 15.8 ± 3.59 mSv respectively. Effective doses for the head and neck were within the typical range of (1-10mSv) for CT examinations whilst abdomen, chest and pelvis were above 10mSv. The average life attributable risk of cancer incidence for each region of examination were determined from the effective dose, sex and age using the model proposed in BEIR VII Report . The average cancer risk incidence for head, neck, chest, abdomen and pelvis examinations were low in the range 1 in 10,000 to 1 in 1,000. There were wide variations in the effective dose values obtained for the same region under examination. This trend calls for the optimization of CT examination protocols to be established to ensure that patient doses are as low as reasonably achievable, economic and social factors being taken into account especially for chest examinations.

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