Search

Objective: To review the technical feasibility of resin microsphere (SIR-Spheres®) yttrium-90 radioembolization prescribed using the medical internal radiation dose (MIRD) model. Methods: All radioembolization procedures for hepatic malignancies using resin microspheres with MIRD model between November 2015 and February 2019 were included in this IRB-approved study (n = 60). Student's T test was used to compare prescribed activity based on MIRD and BSA models. Adverse events were assessed immediately, 30 days, and 6 months post-treatment. Results: Sixty radioembolizations were performed in 54 patients (age 68 ± 9 years, 48–87 years, 35% female). Mean prescribed activity calculated by the MIRD model (target absorbed dose 120–200 Gy for primary and 80–200 Gy for metastatic liver cancers) was 1.7 GBq (0.3–6.4) compared with 0.6 GBq (0.12–2.1) if BSA had been used (p < 0.0001). The prescribed activity was successfully delivered in 93% (56/60) treatments. Prophylactic embolization and anti-reflux catheters were used in 20% (12/60) and 5% (3/60) treatments, respectively. No immediate post-procedural complications occurred. Abdominal pain was the most common clinical Grade 3 CTCAE in 30 days (10%) and 6 months (12%). Radiation pneumonitis occurred in 3 (5%) patients but no radiation-induced gastric ulcer or radiation-induced liver disease occurred. Conclusion: MIRD dosimetry results in higher prescribed activity compared with BSA dosimetry with resin microspheres. MIRD prescribed activity with target absorbed doses up to 200 Gy can be successfully administered without prophylactic embolization in selected patients. Key Points: •MIRD dosimetry results in higher prescribed activity compared with BSA dosimetry for radioembolization. •MIRD dosimetry can be used for yttrium-90 resin microsphere radioembolization with acceptable safety profile. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to determine the feasibility of performing a comprehensive cardiac computed tomographic (CT) examination incorporating stress and rest myocardial perfusion imaging together with coronary computed tomography angiography (CTA). Background: Although cardiac CT can identify coronary stenosis, very little data exist on the ability to detect stress-induced myocardial perfusion defects in humans. Methods: Thirty-four patients who had a nuclear stress test and invasive angiography were included in the study. Dual-source computed tomography (DSCT) was performed as follows: 1) stress CT: contrast-enhanced scan during adenosine infusion; 2) rest CT: contrast-enhanced scan using prospective triggering; and 3) delayed scan: acquired 7 min after rest CT. Images for CTA, computed tomography perfusion (CTP), and single-photon emission computed tomography (SPECT) were each read by 2 independent blinded readers. Results: The DSCT protocol was successfully completed for 33 of 34 subjects (average age 61.4 ± 10.7 years; 82% male; body mass index 30.4 ± 5 kg/m2) with an average radiation dose of 12.7 mSv. On a per-vessel basis, CTP alone had a sensitivity of 79% and a specificity of 80% for the detection of stenosis ≥50%, whereas SPECT myocardial perfusion imaging had a sensitivity of 67% and a specificity of 83%. For the detection of vessels with ≥50% stenosis with a corresponding SPECT perfusion abnormality, CTP had a sensitivity of 93% and a specificity of 74%. The CTA during adenosine infusion had a per-vessel sensitivity of 96%, specificity of 73%, and negative predictive value of 98% for the detection of stenosis ≥70%. Conclusions: Adenosine stress CT can identify stress-induced myocardial perfusion defects with diagnostic accuracy comparable to SPECT, with similar radiation dose and with the advantage of providing information on coronary stenosis. [Copyright &y& Elsevier]