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Introduction: Stereotactic ablative radiotherapy (SABR) offers a curative treatment for lung cancer in patients who are marginal surgical candidates. However, unlike traditional surgery the lung cancer remains in place after treatment. Thus, imaging follow-up for evaluation of recurrence is of paramount importance., Materials and Methods: In this retrospective designed Institutional Review Board-approved study, follow-up contrast-enhanced computed tomography (CT) exams were performed on sixty one patients to evaluate enhancement pattern in the ablation zone at 1, 3, 6, and 12 months after SABR., Results: Eleven patients had recurrence within the ablation zone after SABR. The postcontrast enhancement in the recurrence group showed a washin and washout phenomenon, whereas the radiation-induced lung injury group showed continuous enhancement suggesting an inflammatory process., Conclusions: The textural feature of the ablation zone of enhancement and perfusion as demonstrated in computed tomography nodule enhancement may allow early differentiation of recurrence from radiation-induced lung injury in patients' status after SABR or primary lung cancer.

Objective: The objective of this study was to assess the potential of anterior in beam bismuth shields placed on the abdomen and the pelvis of a RANDO phantom to decrease radiation dose to a simulated fetus., Methods: Thermal luminescent dosimeters irradiated in a RANDO phantom were used to measure radiation dose at 0 weeks and 18 weeks after conception. An 18-week gestation was simulated by adding the corresponding equivalent of super-stuff to account for additional subcutaneous tissue. To assess image quality, a 461A body phantom with low contrast resolution phantom insert was used. The minimum size of low contrast resolution target visualize was recorded with no shielding and 25-cm-wide shielding., Results: With shields, there was a radiation dose reduction of 19% to 23% at 0-week gestation and 16% to 24% at 18-week gestation. No qualitative difference was found in low contrast detectability with the shields., Conclusions: These shields reduce fetal radiation exposure early in pregnancy with acceptable image quality.

Purpose: The objective of this study is to evaluate the effectiveness of nonelectrocardiographic gated multidetector computed tomography (MDCT) performed for the purpose of assessment of pulmonary embolus in the evaluation of myocardial infarction (MI)., Methods: We retrospectively evaluated 147 consecutive patients who had a computed tomography angiogram for pulmonary embolus on a 16-detector MDCT. Of this cohort, we determined 11 patients to have acute MIs based on electrocardiogram, positive troponin levels, and clinical findings and history. Four additional patients were found to have chronic MI based on history. The MDCT data were evaluated by an attending Radiologist, blinded to the clinical data, for quantitative and qualitative attenuations. Each MI was assigned a region of the heart based on its anatomical sections., Results: We were able to detect 10 of 15 MIs, resulting in an overall sensitivity and specificity of 66.6% and 91.4%, respectively. The overall accuracy was 76.7%. If non-Q wave MIs are excluded from the data set, the sensitivity increased to 76.9%. Quantitative analysis of each region of the heart showed that there was a statistically significant difference (P < 0.01) between the infracting regions of the heart (69 +/- 3.3 SEM) and those with normal perfusion (93.3 +/- 1.0 SEM)., Conclusions: While this method did prove to be effective at determining patients who had an MI, the low sensitivity and inability to differentiate chronic from acute myocardial infarction suggest that this technique is very limited in clinical practice.