Radiation absorbed-dose estimates for the liver, spleen, and metaphyseal growth complexes in children undergoing gallium-67 citrate scanning.

Thomas, Sylvia; Gelfand, Michael J.; Burns, G. S.; Purdom, R. C.; Kereiakes, James G.; Maxon, Harry R.

doi:10.1148/radiology.146.3.6572408

Cited by 11 publications

(5 citation statements)

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“…15,16 In order to correct for attenuation without a knowledge of source depth, the conjugate-view method requires only the bodythickness or transmission data using an external source. [4][5][6][7][8][9][10] Macey et al 4 reported a transmission-emission method using a gamma camera and an external uniformity source for the absolute quantitation of Tc-99m in the lungs in clinical studies. Malko et al 5 also proposed a simple conjugate-view method using an external flood source to determine the volume of small or medium size sources ͑Ͻ8 cm͒.…”

Section: Discussionmentioning

confidence: 99%

“…The background count rates equivalent to the source volume, CBGao and CBGbo observed with the camera heads A and B, respectively, are derived as described in Ref. 10. Equations ͑B1͒ and ͑B2͒ are corrected for oversubtraction by CaЈϪCBGaϩCBGaoϭATa•ATc•SA•Co, ͑B5͒…”

Section: B Background Correction Technique Using the Source Depth (Bmentioning

confidence: 99%

“…In order to avoid use of the source depth, the conjugate-view method has been proposed. [4][5][6][7][8][9][10] This method uses the geometric mean ͑GM͒ image of two opposing emission images ͑anteriorand posterior-view images͒.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative planar imaging method for measurement of renal activity by using a conjugate‐emission image and transmission data

et al. 2000

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We are proposing a method to accurately measure renal activity in renography using Tc-99m labeled tracers. This method uses a conjugate-view image and transmission data for attenuation correction, the triple energy window (TEW) method for scatter correction, and background correction techniques that consider the source volume for accurate background activity correction. To examine this method in planar imaging, we performed two renal phantom studies with various uniform background activity concentrations. One study used two ideal box-shaped kidney phantoms with a thickness of 2 or 4 cm in a water tank and the other study employed two real kidney-shaped phantoms in a fillable abdominal cavity. For these studies the kidney phantom-to-background activity concentration ratio (S) was changed from 5 to infinity. The transmission data were obtained with an external Tc-99m line array source. The anterior- and posterior-view emission images were acquired with a dual-headed gamma camera simultaneously and the TEW method was used to correct scatter for the emission and transmission images. The results showed that this method with both the accurate background correction and scatter correction could give depth-independent count rates and could estimate the true count rate with errors of less than 5% for all S values. However, if either accurate background correction or scatter correction was performed alone, the absolute error increased to about 50% for the smaller S values. Our proposed method allows one to accurately and simply measure the renal radioactivity by planar imaging using the conjugate-emission image and transmission data.

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Section: Discussionmentioning

confidence: 99%

Section: B Background Correction Technique Using the Source Depth (Bmentioning

confidence: 99%

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Quantitative planar imaging method for measurement of renal activity by using a conjugate‐emission image and transmission data

et al. 2000

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“…Studies of this topic in recent decades have developed many theoretical simulations of the cumulative dose of radioactive nuclides since each nuclide has a unique radioactive fingerprint. Although most theoretical studies of this issue have applied the medical internal radiation dose (MIRD) calculation model, their conclusions are highly variable [1–10]. Practical studies of internal dose are rarely performed and their results are even more inconsistent [11–15].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of effective dose for a patient under Ga-67 nuclear examination using TLD, water phantom and a simplified model

Chu

Lin

Hsu

et al. 2012

Journal of Radiation Research

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This study evaluated the effective dose of Ga-67 for a patient undergoing Ga-67 citrate nuclear examination by applying thermoluminescent dosimeter (TLD) technique and an indigenous water phantom. The Ga-67 radionuclide remaining in the body inevitably generated a measurable internal dose even though gamma camera scanning took only minutes to complete the clinical examination. For effective simulation of the cumulated effective dose for a patient undergoing examination, 150 TLDs were placed inside the water phantom for 6 days to monitor the gamma ray dose from the distributed Ga-67 citrate solution. The inserted TLDs represented internal organs, and the effective dose was calculated according to data in the ICRP-60 report. The water phantom was designed to model the body of a healthy human weighing 70 kg, and the water that was mixed with Ga-67 citrate solution was slowly replaced with fresh feed water to yield the required biological half life of the phantom. After continuously feeding in fresh water throughout the 6 days of TLD exposure, the TLDs were analyzed to determine the effective doses from the various biological half lives of the phantom. The derived effective dose of 185 MBq Ga-67 citrate solution for male/female (M/F) was 10.7/12.2, 10.7/12.0, 8.7/9.9 and 6.0/6.8 mSv, of biological half lives of 6.0, 4.5, 3.0 and 1.5 days, respectively. Although these experimental results correlated well with earlier empirical studies, they were lower than most calculated values. The cumulated uncertainty in the effective dose was 12.5–19.4%, which was acceptable in terms of both TLD counting statistic and reproducibility.

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“…Absolute measurement of the activity in an organ, in both planar and tomographic examinations, also implies a determination of effective depths and effective attenuation coefficients. The attenuation correction should consider both the thickness of the organ and the depth of the organ in the body as with the conjugate view method (Fleming 1979, Macey and Marshall 1982, Thomas et al 1983. The conjugate view method uses the geometric mean from two opposing views together with the system calibration factor and a correction factor for source attenuation and source thickness where the effective total linear attenuation coefficient across the source is used.…”

Section: Introductionmentioning

confidence: 99%

The determination of the effective attenuation coefficient from effective organ depth and modulation transfer function in gamma camera imaging

Starck

Carlsson

1997

Phys. Med. Biol.

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Absolute measurement of activity implies a determination of effective depths and effective attenuation coefficients. In order to define restoration filters, it is necessary to measure the transfer function, i.e. position a line source at an effective depth for the specific measurement situation. A phantom was designed which can simulate an organ with a certain thickness at a certain depth. The phantom was used to measure transfer functions and a comparison was made with transfer functions from a line source to determine effective depths. Effective attenuation coefficients were calculated for 99mTc, 111In and 201Tl for different organ thicknesses and depths of simulated organs. The effective attenuation coefficient for 99mTc was found to be 0.124 +/- 0.006 cm-1, in good agreement with previously published values. For 111In, the attenuation coefficient decreased with the depth of an organ due to the use of two energy windows in the measurements and a corresponding change in mean photon energy by depth. For 201Tl, the attenuation coefficient decreased with increasing organ thickness due to the increasing fraction of scattered radiation in the 40% energy window used. Using attenuation coefficients of 0.124, 0.184 and 0.11 cm-1 for 99mTc, 201Tl and 111In respectively, the derived equations can be used to calculate the position of a conventional line source for measurements of transfer functions for a specific organ with a certain thickness at a certain depth for definition of different types of restoration filter.

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Radiation absorbed-dose estimates for the liver, spleen, and metaphyseal growth complexes in children undergoing gallium-67 citrate scanning.

Cited by 11 publications

References 0 publications

Quantitative planar imaging method for measurement of renal activity by using a conjugate‐emission image and transmission data

Quantitative planar imaging method for measurement of renal activity by using a conjugate‐emission image and transmission data

Evaluation of effective dose for a patient under Ga-67 nuclear examination using TLD, water phantom and a simplified model

The determination of the effective attenuation coefficient from effective organ depth and modulation transfer function in gamma camera imaging

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