NEED FOR INDIVIDUAL CANCER RISK ESTIMATES IN X-RAY AND NUCLEAR MEDICINE IMAGING

Abstract Some of the ethically most sensitive issues in radiation protection arise at imaging of pregnant—and potentially pregnant—patients and of newborn. This article reviews the current literature and recommendations on imaging during pregnancy and breastfeeding. Risks related to alternative non-ionizing radiation methods are also considered. With few exceptions, exposure of the fetus through radiography, computed tomography (CT) and nuclear medicine imaging can be limited to safe levels, although studies such as abdominal-pelvic CT cannot avoid significant exposure to fetuses. Eight to 10 weeks post-conception, the fetus has a thyroid which starts to concentrate iodide having crossed the placenta barrier resulting in unacceptably high doses to the fetal thyroid after administration of 131I- and even 123I-iodide and other radiopharmaceuticals with a high content of free radioiodine. Many radiopharmaceuticals are excreted through breast milk. Breastfeeding interruption recommendations should be followed to keep the effective dose to the infant below 1 mSv.

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Gene signatures enhance breast cancer risk estimates

PsycEXTRA Dataset ◽

10.1037/e459022008-001 ◽

2008 ◽

Author(s):

Edward R. Winstead

Keyword(s):

Breast Cancer ◽

Breast Cancer Risk ◽

Cancer Risk ◽

Gene Signatures ◽

Risk Estimates

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Patients with fever of unknown origin (FUO): diagnosis by nuclear medicine imaging

Nuklearmedizin ◽

10.1055/s-0038-1623872 ◽

2001 ◽

Vol 40 (03) ◽

pp. 59-70 ◽

Cited By ~ 13

Author(s):

W. Becker ◽

J. Meiler

Keyword(s):

Nuclear Medicine ◽

Fever Of Unknown Origin ◽

Tumor Imaging ◽

White Blood Cells ◽

Unknown Origin ◽

Final Diagnosis ◽

Recurrent Fever ◽

Nuclear Medicine Imaging

SummaryFever of unknown origin (FUO) in immunocompetent and non neutropenic patients is defined as recurrent fever of 38,3° C or greater, lasting 2-3 weeks or longer, and undiagnosed after 1 week of appropriate evaluation. The underlying diseases of FUO are numerous and infection accounts for only 20-40% of them. The majority of FUO-patients have autoimmunity and collagen vascular disease and neoplasm, which are responsible for about 50-60% of all cases. In this respect FOU in its classical definition is clearly separated from postoperative and neutropenic fever where inflammation and infection are more common. Although methods that use in-vitro or in-vivo labeled white blood cells (WBCs) have a high diagnostic accuracy in the detection and exclusion of granulocytic pathology, they are only of limited value in FUO-patients in establishing the final diagnosis due to the low prevalence of purulent processes in this collective. WBCs are more suited in evaluation of the focus in occult sepsis. Ga-67 citrate is the only commercially available gamma emitter which images acute, chronic, granulomatous and autoimmune inflammation and also various malignant diseases. Therefore Ga-67 citrate is currently considered to be the tracer of choice in the diagnostic work-up of FUO. The number of Ga-67-scans contributing to the final diagnosis was found to be higher outside Germany than it has been reported for labeled WBCs. F-l 8-2’-deoxy-2-fluoro-D-glucose (FDG) has been used extensively for tumor imaging with PET. Inflammatory processes accumulate the tracer by similar mechanisms. First results of FDG imaging demonstrated, that FDG may be superior to other nuclear medicine imaging modalities which may be explained by the preferable tracer kinetics of the small F-l 8-FDG molecule and by a better spatial resolution of coincidence imaging in comparison to a conventional gamma camera.

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Nuclear medicine imaging of neuroendocrine tumours

Endocrine Abstracts ◽

10.1530/endoabs.32.s5.2 ◽

2013 ◽

Author(s):

Anders Sundin

Keyword(s):

Nuclear Medicine ◽

Neuroendocrine Tumours ◽

Nuclear Medicine Imaging

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Estimation of dose and cancer risk to newborn from chest X-ray in South-South Nigeria: a call for protocol optimization

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-021-00445-w ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Akintayo Daniel Omojola ◽

Michael Onoriode Akpochafor ◽

Samuel Olaolu Adeneye ◽

Isiaka Olusola Akala ◽

Azuka Anthonio Agboje

Keyword(s):

Cancer Risk ◽

Age Groups ◽

Field Size ◽

Radiological Protection ◽

International Studies ◽

X Ray ◽

Thermoluminescent Dosimeters ◽

Chest X Ray ◽

Neonatal Patient ◽

The Mean

Abstract Background The use of X-ray as a diagnostic tool for complication and anomaly in the neonatal patient has been helpful, but the effect of radiation on newborn stands to increase their cancer risk. This study aims to determine the mean, 50th percentile (quartile 2 (Q2)), and 75th percentile (quartile 3 (Q3)) entrance surface dose (ESD) from anteroposterior (AP) chest X-ray and to compare our findings with other relevant studies. The study used calibrated thermoluminescent dosimeters (TLDs), which was positioned on the central axis of the patient. The encapsulated TLD chips were held to the patients’ body using paper tape. The mean kilovoltage peak (kVp) and milliampere seconds (mAs) used was 56.63(52–60) and 5.7 (5–6.3). The mean background TLD counts were subtracted from the exposed TLD counts and a calibration factor was applied to determine ESD. Results The mean ESDs of the newborn between 1 and 7, 8 and 14, 15 and 21, and 22 and 28 days were 1.09 ± 0.43, 1.15 ± 0.50, 1.19 ± 0.45, and 1.32 ± 0.47 mGy respectively. A one-way ANOVA test shows that there were no differences in the mean doses for the 4 age groups (P = 0.597). The 50th percentile for the 4 age groups was 1.07, 1.26, 1.09, and 1.29 mGy respectively, and 75th percentile were 1.41, 1.55, 1.55, and 1.69 mGy respectively. The mean effective dose (ED) in this study was 0.74 mSv, and the estimated cancer risk was 20.7 × 10−6. Conclusion ESD was primarily affected by the film-focus distance (FFD) and the patient field size. The ESD at 75th percentile and ED in this study was higher compared to other national and international studies. The estimated cancer risk to a newborn was below the International Commission on Radiological Protection (ICRP) limit for fatal childhood cancer (2.8 × 10−2Sv−1).

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Correction for the Partial Volume Effects (PVE) in Nuclear Medicine Imaging: A Post-Reconstruction Analytic Method

Applied Sciences ◽

10.3390/app11146460 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6460

Author(s):

Fabio Di Martino ◽

Patrizio Barca ◽

Eleonora Bortoli ◽

Alessia Giuliano ◽

Duccio Volterrani

Keyword(s):

Nuclear Medicine ◽

Imaging System ◽

Tomographic Reconstruction ◽

Mathematical Expression ◽

Reconstruction Algorithm ◽

Volume Effect ◽

Nuclear Medicine Imaging ◽

Theoretical Derivation ◽

Reconstruction Process ◽

Partial Volume

Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeutic purposes. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, especially for evaluation in Region of Interest (ROI) smaller than the Full Width at Half Maximum (FWHM) of the PSF. The aim of this work is to present a new approach for the correction of PVE, using a post-reconstruction process starting from a mathematical expression, which only requires the knowledge of the FWHM of the final PSF of the imaging system used. After the presentation of the theoretical derivation, the experimental evaluation of this method is performed using a PET/CT hybrid system and acquiring the IEC NEMA phantom with six spherical “hot” ROIs (with diameters of 10, 13, 17, 22, 28, and 37 mm) and a homogeneous “colder” background. In order to evaluate the recovery of quantitative data, the effect of statistical noise (different acquisition times), tomographic reconstruction algorithm with and without time-of-flight (TOF) and different signal-to-background activity concentration ratio (3:1 and 10:1) was studied. The application of the corrective method allows recovering the loss of quantification due to PVE for all sizes of spheres acquired, with a final accuracy less than 17%, for lesion dimensions larger than two FWHM and for acquisition times equal to or greater than two minutes.

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