DSpace Collection:
https://hdl.handle.net/10171/18940
2024-03-29T14:45:08ZSegmental Pneumonitis after Radioembolization
https://hdl.handle.net/10171/68990
Title: Segmental Pneumonitis after Radioembolization
Abstract: Radiation pneumonitis, although infrequent, is a dreaded
complication of radioembolization (RE) with yttrium-90
( 90 Y) microspheres (1). Only 6 cases have been reported
so far (1,2). It develops when 90 Y microspheres reach the
lung filter owing to circumvention of the liver sinusoidal
network through the tumor or arteriovenous channels.
Risk of pneumonitis increases when the lung shunt frac-
tion is > 20% or when the estimated absorbed dose by the
lungs is > 30 Gy (3). During 90 Y RE, occlusion of
extrahepatic arterial branches that feed the tumor from the
systemic vasculature is commonly performed with the aim
to redistribute tumor afferents and administer the treatment
through the hepatic arteries.2018-01-01T00:00:00ZSignificant dose reduction is feasible in FDG PET/CT protocols without compromising diagnostic quality
https://hdl.handle.net/10171/68987
Title: Significant dose reduction is feasible in FDG PET/CT protocols without compromising diagnostic quality
Abstract: Purpose: To reduce the radiation dose to patients by optimizing oncological FDG PET/CT protocols.
Methods: The baseline PET/CT protocol in our institution for oncological PET/CT examinations consisted of the administration of 5.18 MBq/kg of FDG and a CT acquisition with a reference current-time product of 120 mAs. In 2016, FDG activity was reduced to 4.44 and 3.70 MBq/kg and reference CT current-time-product was reduced to 100 and 80 mAs. 322 patients scanned with different protocols were retrospectively evaluated. For each patient, effective dose was calculated. The overall image quality was subjectively rated by the referring physician on a 4-point scale (IQ score: 1 excellent, 2 good, 3 poor but interpretable, 4 poor not interpretable). Image quality was quantitatively evaluated measuring noise in the liver.
Results: CT Results: Effective dose was progressively reduced from 9.5 ± 2.8 to 8.0 ± 2.3 and 6.2 ± 1.5 mSv (p < 0.001). A mean dose reduction of 34.9% was achieved. There was a significant degradation of IQ score (p < 0.05) and noise (p < 0.001). Nevertheless, the number of poor quality studies (IQ score >2) did not increase. PET Results: Effective dose was gradually reduced from 6.5 ± 1.4 to 5.7 ± 1.3 and 5.0 ± 1.0 mSv (p < 0.001). Average dose reduction was 23.4%. IQ score (p < 0.05) and noise (p < 0.001) significantly degraded for lower activity protocols. However, all images with reduced activity were scored as interpretable (IQ score ≤ 3).
Conclusions: A significant radiation dose reduction of 28.7% was reached. Despite a slight reduction in image quality, the new regime was successfully implemented with readers reporting unchanged clinical confidence.2018-01-01T00:00:00ZIs a Technetium-99m Macroaggregated Albumin Scan Essential in the Workup for Selective Internal Radiation Therapy with Yttrium-90? An Analysis of 532 Patients
https://hdl.handle.net/10171/68984
Title: Is a Technetium-99m Macroaggregated Albumin Scan Essential in the Workup for Selective Internal Radiation Therapy with Yttrium-90? An Analysis of 532 Patients
Abstract: Purpose: To determine if baseline patient, tumor, and pretreatment evaluation characteristics could help identify patients who require technetium-99m (99mTc) macroaggregated albumin (99mTc MAA) imaging before selective internal radiation therapy (SIRT).
Materials and methods: In this retrospective analysis, 532 consecutive patients with primary (n = 248) or metastatic (n = 284) liver tumors were evaluated between 2006 and 2015. Variables were compared between patients in whom 99mTc MAA imaging results contraindicated/modified SIRT administration with yttrium-90 (90Y) resin microspheres and those who were treated as initially planned. The 99mTc MAA findings that contraindicated/modified SIRT were a lung shunt fraction (LSF) > 20%, gastrointestinal 99mTc MAA uptake, or a mismatch between 99mTc MAA uptake and intrahepatic tumor distribution.
Results: LSF > 20% and gastrointestinal MAA uptake were observed in 7.5% and 3.9% of patients, respectively, and 11% presented a mismatch. Presence of a single lesion (odds ratio [OR] = 2.4) and vascular invasion (OR = 5.5) predicted LSF > 20%, and GI MAA uptake was predicted by the presence of liver metastases (OR = 3.7) and 99mTc MAA injection through the common/proper hepatic artery (OR = 4.7). Vascular invasion (OR = 4.1) was the only predictor of LSF > 20% and/or GI MAA uptake (sensitivity = 49.2%, specificity = 80.3%, negative predictive value = 92.4%). Previous antiangiogenic treatment (OR = 2.4) and presence of a single lesion (OR = 2.6) predicted mismatch.
Conclusions: Imaging with 99mTc MAA is essential in SIRT workup because baseline characteristics may not adequately predict 99mTc MAA results. Nevertheless, the absence of vascular invasion potentially identifies a group of patients at low risk of SIRT contraindication/modification in whom performing SIRT in a single session (ie, pretreatment evaluation and SIRT on the same day) should be explored.2017-01-01T00:00:00ZMRI fused with prone FDG PET/CT improves the primary tumour staging of patients with breast cancer
https://hdl.handle.net/10171/68981
Title: MRI fused with prone FDG PET/CT improves the primary tumour staging of patients with breast cancer
Abstract: Objective: Our aim was to evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) fused with prone 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in primary tumour staging of patients with breast cancer.
Methods: This retrospective study evaluated 45 women with 49 pathologically proven breast carcinomas. MRI and prone PET-CT scans with time-of-flight and point-spread-function reconstruction were performed with the same dedicated breast coil. The studies were assessed by a radiologist and a nuclear medicine physician, and evaluation of fused images was made by consensus. The final diagnosis was based on pathology (90 lesions) or follow-up ≥ 24 months (17 lesions).
Results: The study assessed 72 malignant and 35 benign lesions with a median size of 1.8 cm (range 0.3-8.4 cm): 31 focal, nine multifocal and nine multicentric cases. In lesion-by-lesion analysis, sensitivity, specificity, positive and negative predictive values were 97%, 80%, 91% and 93% for MRI, 96%, 71%, 87%, and 89% for prone PET, and 97%. 94%, 97% and 94% for MRI fused with PET. Areas under the curve (AUC) were 0.953, 0.850, and 0.983, respectively (p < 0.01).
Conclusions: MRI fused with FDG-PET is more accurate than FDG-PET in primary tumour staging of breast cancer patients and increases the specificity of MRI.2017-01-01T00:00:00Z