Radiation Protection and Dosimetry in PET and PET/CT

Towson, Jocelyn; Eberl, Stefan

doi:10.1007/1-84628-187-3_4

Cited by 7 publications

(4 citation statements)

References 46 publications

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“…However, PET/CT investigations lead to exposure of patients from the internally administered PET radiopharmaceutical and externally from the X-rays generated by the CT 1 . Due to this fact, it is a challenging area of radiation safety in diagnostic radiation medicine 3 . The radiation dose to the patient from a PET/CT scan depends on the PET/CT protocol, the patient's size and physiology, amount of injected activity and the make and model of the PET/CT scanner 4 .…”

mentioning

confidence: 99%

Estimation of radiation dose to patients from^[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Kaushik¹,

Jaimini²,

Tripathi³

et al. 2015

Indian J Med Res

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Background & objectives:There is a growing concern over the radiation exposure of patients from undergoing 18FDG PET/CT (18F-fluorodeoxyglucose positron emission tomography/computed tomography) whole body investigations. The aim of the present study was to study the kinetics of 18FDG distributions and estimate the radiation dose received by patients undergoing 18FDG whole body PET/CT investigations.Methods:Dynamic PET scans in different regions of the body were performed in 49 patients so as to measure percentage uptake of 18FDG in brain, liver, spleen, adrenals, kidneys and stomach. The residence time in these organs was calculated and radiation dose was estimated using OLINDA software. The radiation dose from the CT component was computed using the software CT-Expo and measured using computed tomography dose index (CTDI) phantom and ionization chamber. As per the clinical protocol, the patients were refrained from eating and drinking for a minimum period of 4 h prior to the study.Results:The estimated residence time in males was 0.196 h (brain), 0.09 h (liver), 0.007 h (spleen), 0.0006 h (adrenals), 0.013 h (kidneys) and 0.005 h (stomach) whereas it was 0.189 h (brain), 0.11 h (liver), 0.01 h (spleen), 0.0007 h (adrenals), 0.02 h (kidneys) and 0.004 h (stomach) in females. The effective dose was found to be 0.020 mSv/MBq in males and 0.025 mSv/MBq in females from internally administered 18FDG and 6.8 mSv in males and 7.9 mSv in females from the CT component. For an administered activity of 370 MBq of 18FDG, the effective dose from PET/CT investigations was estimated to be 14.2 mSv in males and 17.2 mSv in females.Interpretation & conclusions:The present results did not demonstrate significant difference in the kinetics of 18FDG distribution in male and female patients. The estimated PET/CT doses were found to be higher than many other conventional diagnostic radiology examinations suggesting that all efforts should be made to clinically justify and carefully weigh the risk-benefit ratios prior to every 18FDG whole body PET/CT scan.

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confidence: 99%

Estimation of radiation dose to patients from^[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Kaushik¹,

Jaimini²,

Tripathi³

et al. 2015

Indian J Med Res

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“…The safety considerations for such hybrid systems mainly concern exposure of the patients to the harmful X-ray radiation originating from the CT-modality, which is reviewed extensively in the literature. 209 On the other hand, the tracers applied for both PET and SPECT imaging are less of a problem in terms of radiotoxicity, since they are generally short-lived radioisotopes that are excreted from the body by the renal system within 24 to 48 h after their intravenous administration. In this context, it is important to realize that the picomolar amounts of tracers administered for radionuclide imaging omit any chemotoxicity concerns, even if the elements involved are chemically toxic by nature.…”

Section: Toxicity Assessmentmentioning

confidence: 99%

“…The evolution of radionuclide imaging shows a clear preference for diagnosis where the high sensitivity of PET/SPECT is combined with the high anatomic resolution of CT. The safety considerations for such hybrid systems mainly concern exposure of the patients to the harmful X-ray radiation originating from the CT-modality, which is reviewed extensively in the literature . On the other hand, the tracers applied for both PET and SPECT imaging are less of a problem in terms of radiotoxicity, since they are generally short-lived radioisotopes that are excreted from the body by the renal system within 24 to 48 h after their intravenous administration.…”

Section: Toxicity Assessmentmentioning

confidence: 99%

Polysaccharide-Based Theranostic Systems for Combined Imaging and Cancer Therapy: Recent Advances and Challenges

Gupta

Sood

Fuhrer

et al. 2022

ACS Biomater. Sci. Eng.

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Designing novel systems for efficient cancer treatment and improving the quality of life for patients is a prime requirement in the healthcare sector. In this regard, theranostics have recently emerged as a unique platform, which combines the benefits of both diagnosis and therapeutics delivery. Theranostics have the desired contrast agent and the drugs combined in a single carrier, thus providing the opportunity for real-time imaging to monitor the therapy results. This helps in reducing the hazards related to treatment overdose or underdose and gives the possibility of personalized therapy. Polysaccharides, as natural biomolecules, have been widely explored to develop theranostics, as they act as a matrix for simultaneously loading both contrast agents and drugs for their utility in drug delivery and imaging. Additionally, their remarkable physicochemical attributes (biodegradability, satisfactory safety profile, abundance, and diversity in functionality and charge) can be tuned via postmodification, which offers numerous possibilities to develop theranostics with desired characteristics. Hence, we provide an overview of recent advances in polysaccharide matrix-based theranostics for drug delivery combined with magnetic resonance imaging, computed tomography, positron emission tomography, single photon emission computed tomography, and ultrasound imaging. Herein, we also summarize the toxicity assessment of polysaccharides, associated contrast agents, and nanotoxicity along with the challenges and future research directions.

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“…[4][5][6] To evaluate risk-benefit ratios and improve patient protection, it is essential to estimate the radiation dose from imaging modalities that are based on ionizing radiation. In a typical PET/CT study, the total effective radiation dose comprises the radiation dose from a X-ray topogram image, 7 lutetium-based scintillators (in most PET scanners), 8 (low dose) CT scan, and on top of that from the PET tracer. In patients with nononcological diseases, the total amount of radiation dose, especially for younger patients or even healthy volunteers poses a stumbling block for using PET, limiting its potentially valuable role.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐low dose CT scanning for PET/CT

Mostafapour,

Greuter,

van Snick

et al. 2023

Medical Physics

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BackgroundThe use of computed tomography (CT) for attenuation correction (AC) in whole‐body PET/CT can result in a significant contribution to radiation exposure. This can become a limiting factor for reducing considerably the overall radiation exposure of the patient when using the new long axial field of view (LAFOV) PET scanners. However, recent CT technology have introduced features such as the tin (Sn) filter, which can substantially reduce the CT radiation dose.PurposeThe purpose of this study was to investigate the ultra‐low dose CT for attenuation correction using the Sn filter together with other dose reduction options such as tube current (mAs) reduction. We explore the impact of dose reduction in the context of AC‐CT and how it affects PET image quality.MethodsThe study evaluated a range of ultra‐low dose CT protocols using five physical phantoms that represented a broad collection of tissue electron densities. A long axial field of view (LAFOV) PET/CT scanner was used to scan all phantoms, applying various CT dose reduction parameters such as reducing tube current (mAs), increasing the pitch value, and applying the Sn filter. The effective dose resulting from the CT scans was determined using the CTDIVol reported by the scanner. Several voxel‐based and volumes of interest (VOI)‐based comparisons were performed to compare the ultra‐low dose CT images, the generated attenuation maps, and corresponding PET images against those images acquired with the standard low dose CT protocol. Finally, two patient datasets were acquired using one of the suggested ultra‐low dose CT settings.ResultsBy incorporating the Sn filter and adjusting mAs to the lowest available value, the radiation dose in CT images of PBU‐60 phantom was significantly reduced; resulting in an effective dose of nearly 2% compared to the routine low dose CT protocols currently in clinical use. The assessment of PET images using VOI and voxel‐based comparisons indicated relative differences (RD%) of under 6% for mean activity concentration (AC) in the torso phantom and patient dataset and under 8% for a source point in the CIRS phantom. The maximum RD% value of AC was 14% for the point source in the CIRS phantom. Increasing the tube current from 6 mAs to 30 mAs in patients with high BMI, or with arms down, can suppress the photon starvation artifact, whilst still preserving a dose reduction of 90%.ConclusionsIntroducing a Sn filter in CT imaging lowers radiation dose by more than 90%. This reduction has minimal effect on PET image quantification at least for patients without Body Mass Index (BMI) higher than 30. Notably, this study results need validation using a larger clinical PET/CT dataset in the future, including patients with higher BMI.

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Radiation Protection and Dosimetry in PET and PET/CT

Cited by 7 publications

References 46 publications

Estimation of radiation dose to patients from^[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Estimation of radiation dose to patients from^[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Polysaccharide-Based Theranostic Systems for Combined Imaging and Cancer Therapy: Recent Advances and Challenges

Ultra‐low dose CT scanning for PET/CT

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Radiation Protection and Dosimetry in PET and PET/CT

Cited by 7 publications

References 46 publications

Estimation of radiation dose to patients from[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Estimation of radiation dose to patients from[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Polysaccharide-Based Theranostic Systems for Combined Imaging and Cancer Therapy: Recent Advances and Challenges

Ultra‐low dose CT scanning for PET/CT

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Estimation of radiation dose to patients from^[18]FDG whole body PET/CT investigations using dynamic PET scan protocol

Estimation of radiation dose to patients from^[18]FDG whole body PET/CT investigations using dynamic PET scan protocol