Radionuclide bone scan SPECT-CT: lowering the dose of CT significantly reduces radiation dose without impacting CT image quality (original) (raw)
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Radiation Dose Reduction Strategy for SPECT/CT Bone Scan
Purpose: The aim of this study is to introduce the optimization method of CT parameters to reduce patient radiation exposure in bone SPECT/CT while maintaining image quality. The results of the new protocol were then compared to the results of the standard protocol saved in the nuclear medicine department`s data at King Abdullah Medical City.Methodology: First part: Using Deluxe Jaszczak Phantom. The cylindrical phantom consisted of six bottles in a pie arrangement. These bottles were placed in the source tank. SPECT/CT scans were carried out with different x-ray tube current values (10, 20, 30, 40, 50, and 60 mA) at three different slices of thicknesses (2.5, 3.75, and 5mm). The contrast ratio (CR) and coefficients of variation (COV) in the SPECT images as well as the signal-to-noise ratio (SNR) and were all measured. An optimal acquisition protocol of SPECT/CT images with no artifacts on both CT and SPECT images, and acceptable CR, COV, and SNR values were obtained. Second part: T...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2007
The purpose of this prospective study was to assess the role of SPECT/multislice low-dose (Msl) CT as a constituent in the imaging algorithm of nononcologic patients referred for 99mTc-methylene diphosphonate bone scintigraphy (BS). SPECT/CT was performed using a novel hybrid system, which incorporates a gamma-camera and a multislice low-dose CT, on 76 consecutive nononcologic patients with nonspecific scintigraphic findings, which required further correlation with morphologic data. SPECT/MslCT was of added clinical value in 89% of the patients. Characterizing scintigraphic lesions by their morphologic appearance, SPECT/MslCT reached a final diagnosis in 49 of 85 (58%) nonspecific scintigraphic bone lesions found in 59% (45/76) of patients, obviating the need to perform additional imaging. In another 30% of patients (23/76), SPECT/MslCT data optimized the patients' imaging algorithm as the performance of a full-dose CT, MRI, or labeled-leukocyte scintigraphy as the next imaging ...
Image quality and radiation exposure in 320-row temporal bone computed tomography
Dentomaxillofacial Radiology, 2010
Objectives: The aim was to define image quality and radiation exposure in the recently introduced 320-row CT of the temporal bone (tb) in comparison to a 16-row tb CT. Methods: A cadaveric head phantom was used for repeated tb volume CT studies (80-120 kV, 25-150 mAs), performed in a 320-row scanner (single rotation, 0.5 mm slice thickness, kernel FC 51) in comparison to 16-row helical CT using standard acquisition parameters (SAP) of 120 kV and 75 mAs (kernel FC 53). Qualitative image evaluation was performed by two radiologists using a 5-point visual analogue scale. Image noise (D SD) was determined by region of interest (ROI) based measurements in cadaveric as well as water phantom studies. Dosimetric measurements of the effective dose (ED) and organ dose (OD) of the lens were performed. Results: Image quality of 320-row tb CT was equivalent to 16-row CT for SAP scans, resulting in image noise levels (D SD 16-/320-row) of 109/237 and 206/446 for air and bone respectively. D SD differences were predominantly (.90%) attributable to the different kernels available for tb studies in 16-and 320-row CT. Radiation exposure for 16-/320-row SAP scans amounted to 0.36/0.30 mSv (ED) and 10.0/8.4 mGy (lens dose). Conclusion: 320-row volume acquisition in tb CT delivers equivalent image quality to 16row CT while decreasing radiation exposure figures by one sixth. Image noise increase in 320row CT is negligible with respect to image quality.
SPECT-CT in routine clinical practice
Nuclear Medicine Communications, 2012
Objective To assess the patient radiation dose during routine clinical single-photon emission computed tomography-computed tomography (SPECT-CT) and measure the increase as compared with SPECT alone. Materials and methods Data pertaining to 357 consecutive patients who had undergone radioisotope imaging along with SPECT-CT of a selected volume were retrospectively evaluated. Dose of the injected radiopharmaceutical (MBq) was noted, and the effective dose (mSv) was calculated as per International Commission on Radiological Protection (ICRP) guidelines. The volume-weighted computed tomography dose index (CTDIvol) and dose length product of the CT were also assessed using standard phantoms. The effective dose (mSv) due to CT was calculated as the product of dose length product and a conversion factor depending on the region of investigation, using ICRP guidelines. The dose due to CT was compared among different investigations. The increase in effective dose was calculated as CT dose expressed as a percentage of radiopharmaceutical dose. Results The per-patient CT effective dose for different studies varied between 0.06 and 11.9 mSv. The mean CT effective dose was lowest for 99m Tc-ethylene cysteine dimer brain SPECT-CT (0.9±0.7) and highest for 99m Tc-methylene diphosphonate bone SPECT-CT (4.2±2.8). The increase in radiation dose (SPECT-CT vs. SPECT) varied widely (2.3-666.4% for 99m Tc-tracers and 0.02-96.2% for 131 I-tracers). However, the effective dose of CT in SPECT-CT was less than the values reported for conventional CT examinations of the same regions. Conclusion Addition of CT to nuclear medicine imaging in the form of SPECT-CT increases the radiation dose to the patient, with the effective dose due to CT exceeding the effective dose of RP in many instances. Hence, appropriate utilization and optimization of the protocols of SPECT-CT is needed to maximize benefit to patients. Nucl Med Commun 33:926-932
European Journal of Radiology, 2018
We compared the image quality and radiation dose of flat-panel CT (FPCT) and multi-slice CT (MSCT) performed respectively with an angiographic unit and a 128-slice CT scanner. We investigated whether the higher spatial resolution of FPCT translated into higher image quality and we sought to eliminate inter-subject variability by scanning temporal bone specimens with both techniques. Materials and methods: Fifteen temporal bone specimens were imaged with FPCT and MSCT. Two neuroradiologists experienced in otoradiology evaluated 30 anatomical structures with a 0-2 score; 18 structures important from a clinical perspective were assigned a twofold value in calculation of the overall score. The radiation dose was calculated through the use of an anthropomorphic phantom. Results: The image quality was significantly higher for FPCT than MSCT for 10 of the 30 anatomical structures; the overall score was also significantly higher for FPCT (p = 0.001). The equivalent dose of the two techniques was very similar, but with different effective doses to the organs. Conclusion: FPCT performed on an angiographic unit provides higher image quality in temporal bone assessment compared to MSCT performed on a 128-slice CT scanner thanks to its higher spatial resolution, with comparable equivalent doses but different effective doses to the organs.
EJNMMI research, 2018
xSPECT Bone® (xB) is a new reconstruction algorithm developed by Siemens® in bone hybrid imaging (SPECT/CT). A CT-based tissue segmentation is incorporated into SPECT reconstruction to provide SPECT images with bone anatomy appearance. The objectives of this study were to assess xB/CT reconstruction diagnostic reliability and accuracy in comparison with Flash 3D® (F3D)/CT in clinical routine. Two hundred thirteen consecutive patients referred to the Brest Nuclear Medicine Department for non-oncological bone diseases were evaluated retrospectively. Two hundred seven SPECT/CT were included. All SPECT/CT were independently interpreted by two nuclear medicine physicians (a junior and a senior expert) with xB/CT then with F3D/CT three months later. Inter-observer agreement (IOA) and diagnostic confidence were determined using McNemar test, and unweighted Kappa coefficient. The study objectives were then re-assessed for validation through > 18 months of clinical and paraclinical follow...
Annals of Nuclear Medicine, 2013
Hybrid imaging, such as SPECT/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. Objectives The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). Methods 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. Results The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85 % with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. Conclusions The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose. Keywords SPECT/CT Á Effective dose Á Background Equivalent Radiation Time Á Radiopharmaceutical C. Montes and P. Tamayo contributed equally to this work.
Indian Journal of Nuclear Medicine, 2011
Study design: Planar bone scans with SPECT and SPECT + CT were performed in those patients who underwent peri-operative evaluation for vertebroplasty. The scans were evaluated separately to identify the "culprit" vertebra (e) by two readers and their results were analyzed. Objective: Use of planar and SPECT bone scan for identifying the "culprit" vertebra (e) for vertebroplasty is well established. SPECT + CT is a relatively recent imaging tool providing co-registered fused images. Theoretical advantages of SPECT + CT over conventional SPECT imaging needs to be evaluated and documented. Summary of Background Data: Percutaneous stabilization of collapsed vertebra by bone cement has now become a standard procedure. However, it is essential to localize the correct vertebra. Imaging modalities like CT scan provides structural or anatomical information where as bone scan (planar + SPECT images) provides more functional or physiological information. Combination of these two imaging modalities is expected to provide much more than information obtained by any one imaging modality separately. To the best our knowledge, there is no reference available in the literature adopting this approach. Materials and Methods: Two expert readers, blinded to patient history, evaluated the scans. They independently analyzed planar + SPECT only images followed by SPECT/CT fused images with the aim to identify the acutely fractured vertebra for vertebroplasty. Results: Interpretations changed, on average, 50% of the time as a result of the additional information provided by SPECT + CT. SPECT + CT more precisely localizes tracer abnormalities in the vertebra compared to SPECT imaging alone Conclusion: The greatest value of co-registered SPECT + CT bone scan lies in the accurate localization of affected vertebrae in complicated cases of multiple collapsed vertebrae of different ages as well as in the post-vertebroplasty setting.