Organ doses to adult patients for chest CT

Huda, Walter; Sterzik, Alexander; Tipnis, Sameer; Schoepf, U. Joseph

doi:10.1118/1.3298015

Cited by 56 publications

(37 citation statements)

References 18 publications

(14 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our study shows that the lung dose in CT of thorax imaging is 9.1 and 2.1 mGy for 120 kV and 80 kV respectively. In a study by Huda et al (25) , organ dose in CT was reported based on dose measurements on CTDI phantom. In this study dose in lung and heart were 6.8 mGy and 10.3 mGy respectively with 120 kV, 100 mAs and 12 cm scan length.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation

Mohammadi

Alam

Geraily

et al. 2016

IJRR

View full text Add to dashboard Cite

Background: This study presents pa ent specific and organ dose es ma on in computed tomography (CT) imaging of thorax directly from pa ent CT image using Monte Carlo simula on. Pa ent's CT image is considered as the pa ent specific phantom and the best representa ve of pa ent physical index in order to calculate specific organ dose. Materials and Methods: EGSnrc / BEAMnrc Monte Carlo (MC) System was used for CT scanner simula on and DOSXYZnrc was used in order to produce pa ent specific phantom and irradia on of photons to phantom in step and shoot mode (axial mode). In order to calculate pa ent thorax organ dose, pa ent CT image of thorax as voxelized phantom was divided to a 64x64x20 matrix and 6.25 x 6.25 x 6.25 mm 3 voxel size and this phantom was imported to DOSXYZnrc code. MC results in unit of Gy/par cle were converted to absorbed dose in unit of mGy by a conversion factor (CF). We calculated pa ent thorax organ dose in MC simula on from all irradiated slices, in 120 kV and 80 kV photon energies. Results: Effec ve dose was obtained from organ dose and organ weigh ng factor. Esophagus and spinal cord received the lowest, and bone received the highest dose. In our study, effec ve dose in CT of thorax was 7.4 mSV and 1.8 mSv in 120 and 80 kV, respec vely. Conclusion: The results of this study might be used to provide the actual pa ent organ dose in CT imaging and calcula on of real effec ve dose based on organ dose.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Dose to transverse process and spinous process are more than body of spine. In most studies, organ dose was calculated based on dose measurements in CTDI phantom (25)(26)(27) . In these studies, organ dose level was reported for a reference man and was not patient speci ic.…”

Section: Discussionmentioning

confidence: 99%

Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation

Mohammadi

Alam

Geraily

et al. 2016

IJRR

View full text Add to dashboard Cite

show abstract

“…Data have been presented that can correct for patient body size in chest, cardiac, and abdominal imaging by modeling patients as mass equivalent cylinders of water, and making use of published scientific data on relative doses in cylinders of varying diameter. 33,35,36 In the chest, for example, it has been shown that a 50 kg patient is expected to have doses that are 18% higher than those in a 70 kg adult, whereas a 100 kg patient will have doses that are 18% lower. 33 When using R K values for estimating patient organ doses, it is essential that appropriate corrections are applied to take into account patient size.…”

Section: 27mentioning

confidence: 99%

“…33,35,36 In the chest, for example, it has been shown that a 50 kg patient is expected to have doses that are 18% higher than those in a 70 kg adult, whereas a 100 kg patient will have doses that are 18% lower. 33 When using R K values for estimating patient organ doses, it is essential that appropriate corrections are applied to take into account patient size. Turner et al have shown as an extension to their earlier work, that patient size corrections are feasible for CTDI-based organ dose estimates in abdominal CT examinations.…”

Section: 27mentioning

confidence: 99%

“…The influence of scan length on organ doses have recently been investigated and empirical correction factors can be used to account for partial organ irradiation. 27,[33][34][35] In addition, software packages such as the ImPACT CT Patient Dosimetry Calculator 15 and others readily permit the empirical investigation of partial body irradiations, and how this is likely to affect the dose to any particular organ.…”

Section: 27mentioning

confidence: 99%

See 1 more Smart Citation

In-patient to isocenter KERMA ratios in CT

et al. 2011

Self Cite

View full text Add to dashboard Cite

Purpose: To estimate in-patient KERMA for specific organs in computed tomography (CT) scanning using ratios to isocenter free-in-air KERMA obtained using a Rando phantom. Method: A CT scan of an anthropomorphic phantom results in an air KERMA K at a selected phantom location and air kerma K CT at the CT scanner isocenter when the scan is repeated in the absence of the phantom. The authors define the KERMA ratio (R K ) as K= K CT , which were experimentally determined in a Male Rando Phantom using lithium fluoride chips (TLD-100). R K values were obtained for a total of 400 individual point locations, as well as for 25 individual organs of interest in CT dosimetry. CT examinations of Rando were performed on a GE LightSpeed Ultra scanner operated at 80 kV, 120 kV, and 140 kV, as well as a Siemens Sensation 16 operated at 120 kV. Results: At 120 kV, median R K values for the GE and Siemens scanners were 0.60 and 0.64, respectively. The 10th percentile R K values ranged from 0.34 at 80 kV to 0.54 at 140 kV, and the 90th percentile R K values ranged from 0.64 at 80 kV to 0.78 at 140 kV. The average R K for the 25 Rando organs at 120 kV was 0.61 6 0.08. Average R K values in the head, chest, and abdomen showed little variation. Relative to R K values in the head, chest, and abdomen obtained at 120 kV, R K values were about 12% lower in the pelvis and about 58% higher in the cervical spine region. Average R K values were about 6% higher on the Siemens Sensation 16 scanner than the GE LightSpeed Ultra. Reducing the x-ray tube voltage from 120 kV to 80 kV resulted in an average reduction in R K value of 34%, whereas increasing the x-ray tube voltage to 140 kV increased the average R K value by 9%. Conclusions: In-patient to isocenter relative KERMA values in Rando phantom can be used to estimate organ doses in similar sized adults undergoing CT examinations from easily measured air KERMA values at the isocenter (free in air). Conversion from in-patient air KERMA values to tissue dose would require the use of energy-appropriate conversion factors.

show abstract

Organ doses evaluation for chest computed tomography procedures with TL dosimeters: Comparison with Monte Carlo simulations

Giansante

Martins

Nersissian

et al. 2018

J Applied Clin Med Phys

View full text Add to dashboard Cite

PurposeTo evaluate organ doses in routine and low‐dose chest computed tomography (CT) protocols using an experimental methodology. To compare experimental results with results obtained by the National Cancer Institute dosimetry system for CT (NCICT) organ dose calculator. To address the differences on organ dose measurements using tube current modulation (TCM) and fixed tube current protocols.MethodsAn experimental approach to evaluate organ doses in pediatric and adult anthropomorphic phantoms using thermoluminescent dosimeters (TLDs) was employed in this study. Several analyses were performed in order to establish the best way to achieve the main results in this investigation. The protocols used in this study were selected after an analysis of patient data collected from the Institute of Radiology of the School of Medicine of the University of São Paulo (InRad). The image quality was evaluated by a radiologist from this institution. Six chest adult protocols and four chest pediatric protocols were evaluated. Lung doses were evaluated for the adult phantom and lung and thyroid doses were evaluated for the pediatric phantom. The irradiations were performed using both a GE and a Philips CT scanner. Finally, organ doses measured with dosimeters were compared with Monte Carlo simulations performed with NCICT.ResultsAfter analyzing the data collected from all CT examinations performed during a period of 3 yr, the authors identified that adult and pediatric chest CT are among the most applied protocol in patients in that clinical institution, demonstrating the relevance on evaluating organ doses due to these examinations. With regards to the scan parameters adopted, the authors identified that using 80 kV instead of 120 kV for a pediatric chest routine CT, with TCM in both situations, can lead up to a 28.7% decrease on the absorbed dose. Moreover, in comparison to the standard adult protocol, which is performed with fixed mAs, TCM, and ultra low‐dose protocols resulted in dose reductions of up to 35.0% and 90.0%, respectively. Finally, the percent differences found between experimental and Monte Carlo simulated organ doses were within a 20% interval.ConclusionsThe results obtained in this study measured the impact on the absorbed dose in routine chest CT by changing several scan parameters while the image quality could be potentially preserved.

show abstract

Organ doses to adult patients for chest CT

Cited by 56 publications

References 18 publications

Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation

Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation

In-patient to isocenter KERMA ratios in CT

Organ doses evaluation for chest computed tomography procedures with TL dosimeters: Comparison with Monte Carlo simulations

Contact Info

Product

Resources

About