Virtual Injection Software Reduces Radiation Exposure and Procedural Time of Prostatic Artery Embolization Performed with Cone-Beam CT.

PURPOSE: To evaluate the impact of virtual injection software (VIS) use during cone-beam computed tomography (CT)-guided prostatic artery embolization (PAE) on both patient radiation exposure and procedural time. MATERIALS AND METHODS: This institutional review board (IRB)-approved comparative retrospective study analyzed the treatment at a single institution of 131 consecutive patients from January 2020 to May 2022. Cone-beam CT was used with (Group 1, 77/131; 58.8%) or without VIS (Group 2, 54/131, 41.2%). Radiation exposure (number of digital subtraction angiography [DSA] procedures), dose area product (DAP), total air kerma (AK), peak skin dose (PSD), fluoroscopy time (FT), and procedure time (PT) were recorded. The influences of age, body mass index, radial access, and use of VIS were assessed. RESULTS: In bivariate analysis, VIS use (Group 1) showed reduction in the number of DSA procedures (8.6 ± 3.7 vs 16.8 ± 4.3; P < .001), DAP (110.4 Gy·cm2 ± 46.8 vs 140.5 Gy·cm2 ± 61; P < .01), AK (642 mGy ± 451 vs 1,150 mGy ± 637; P = .01), PSD (358 mGy ± 251 vs 860 mGy ± 510; P = .001), FT (35.6 minutes ± 15.4 vs 46.6 minutes ± 20; P = .001), and PT (94.6 minutes ± 41.3 vs 115.2 minutes ± 39.6, P = .005) compared to those in Group 2. In multivariate analysis, AK, PSD, FT, and PT reductions were associated with VIS use (P < .001, P < .001, P = .001, and P = .006, respectively). CONCLUSIONS: The use of VIS during PAE performed under cone-beam CT guidance led to significant reduction in patient radiation exposure and procedural time.

iQMetrix-CT: New software for task-based image quality assessment of phantom CT images.

The purpose of this article was to explain how the new iQMetrix-CT software works, as well as to describe its current potential and discuss its future applications. iQMetrix-CT was developed by a working group from the French Society of Medical Physicists (SFPM). This software calculates three advanced metrics, which have been adapted to take into account the non-linear and non-stationary properties of iterative reconstruction algorithms. Noise power spectrum is calculated to assess noise texture and noise magnitude in the frequency domain. The task-based transfer function is computed to assess the spatial resolution under conditions of contrast and noise similar to the lesions encountered in clinical practice. Finally, the detectability index is used to estimate the radiologist's ability to perform a given task such as detecting a simulated lesion. These metrics are very useful to evaluate the performance of reconstruction algorithms in term of image quality and optimize the doses of a given protocol or to evaluate and compare a new technology.

Percutaneous screw fixation of pelvic bone metastases using cone-beam computed tomography navigation.

PURPOSE: The purpose of this study was to evaluate the efficacy of cone-beam computed tomography (CBCT) navigation to achieve percutaneous screw fixation (PSF) of pelvic bone metastases (PBM). MATERIALS AND METHODS: Thirty-five consecutive patients (12 men and 23 women; mean age, 62 ± 11.3 [SD]; range: 39-89 years) treated between 2019 and 2021 were retrospectively included. CBCT navigation software was systematically used. Manual drawing of the entry point (MDEP) was performed when CBCT automatic positioning failed. Influence of metastasis pattern, ablation, body mass index, number of screws, and MDEP on procedure duration (PD) and total Air Kerma (AK) was evaluated. Local pain was assessed before, one and six months after treatment. Variables were compared using Pearson correlation, Student t and Wilcoxon tests. RESULTS: Seventy-five screws were inserted successfully (mean: 2.1 ± 1.1 [SD]; range: 1-5 per patient). CBCT automatic positioning was obtained for 41 screws (55%, 41/75), whereas 34 (45%, 34/75) required MDEP. Mean procedure duration, fluoroscopy time, kerma air product and AK were 73.3 ± 44.8 (SD) min (range: 19-233 min), 13.1 ± 9.5 (SD) min (range: 1.4-38.6 min), 73.8 ± 66.3 (SD) Gy.cm2 (range: 11.6-303.7 Gy.cm2) and 301.7 ± 242.1 (SD) mGy (range: 49.4-1111.5 mGy), respectively. Procedure duration was not significantly longer in patients with mixed or blastic PBM compared to those with lytic PBM or when performing ablation, and no significant correlations were observed with the number of screws inserted (P = 0.19), MDEP (P = 0.37) and BMI (P = 0.44). No adverse events were reported during the follow-up (median: 6 months; IQR: 6-6.5 months). Thirteen patients died during the follow-up related to cancer progression. Local pain decreased from 35 ± 32 (SD) mm (range: 0-10 mm) to 11 ± 20 (SD) mm (range: 0-80 mm) at one month (P = 0.001); and to 22 ± 23 (SD) mm (range: 0-60 mm) at six months (P = 0.001). CONCLUSION: CBCT navigation allows to effectively performing PSF of PBM even in the presence of steep angulations.

Expandable Intravertebral Implant in Cancer-Related Vertebral Compression Fractures: A Retrospective Review of 36 Implantations.

The purpose of this retrospective review was to evaluate SpineJack implantation in cancer-related vertebral compression fractures in 13 consecutive patients (mean age, 62.8 years ± 18.8). A total of 36 devices were inserted at 20 levels (13 [65%] lumbar and 7 [35%] thoracic vertebrae), with a mean Spinal Instability Neoplastic Score of 9.1 ± 2.1. Vertebral height restoration was observed in 10 levels (50%), with a mean height restoration of 5.6 mm ± 2.2 (interquartile range [IQR], 4-7.5). A total of 6 cement leakages were observed in 3 (23%) patients without clinical consequences. No severe adverse events were observed. One adjacent fracture occurred. Average pain scores on the visual analog scale significantly improved from 5.5 ± 1.8 (IQR, 4-7) preoperatively to 1.5 ± 2.2 (IQR, 0-3.3) at 1 month (P < .01) and to 1.5 ± 1.3 (IQR, 0.3-2.8) at 6 months (P < .01). In this small cohort, SpineJack offered pain relief in cancer-related fractures without an observed increase in adverse events.

Percutaneous Image-Guided Vertebral Fixation in Cancer-Related Vertebral Compression Fractures: A Case Series Study.

Background and objectives: Cancer-related vertebral compression fractures (VCF) may cause debilitating back pain and instability, affecting the quality of life of cancer patients. To further drive cement deposition during vertebroplasty, the aims of this restrospective case series study were to report the feasibility, safety and short term efficacy (≤6 months) of percutaneous vertebral fixation in cancer-related vertebral compression fractures using various intravertebral implants. Methods: All consecutive cancer patients treated with percutaneous vertebral fixation for VCF were retrospectively included. Various devices were inserted percutaneously under image guidance and filled by cement. Descriptive statistics were used and a matched paired analysis of pain scores was performed to assess for changes following interventions. Results: A total of 18 consecutive patients (12 women (66.6%) and 6 men (33.3%); mean age 59.7 ± 15.5 years) were included. A total of 42 devices were inserted in 8 thoracic and 16 lumbar vertebrae. Visual analogue scale measurement significantly improved from 5.6 ± 1.8 preoperatively to 1.5 ± 1.7 at 1 week (p < 0.01) and to 1.5 ± 1.3 at 6 months (p < 0.01). No severe adverse events were observed, but three adjacent fractures occurred between 1 week and 5 months after implantation. Conclusions: Percutaneous vertebral fixation of cancer-related VCF is feasible and safe and allows pain relief.

Ergonomics in Interventional Radiology: Awareness Is Mandatory.

Ergonomics in interventional radiology has not been thoroughly evaluated. Like any operators, interventional radiologists are exposed to the risk of work-related musculoskeletal disorders. The use of lead shielding to radiation exposure and the lack of ergonomic principles developed so far contribute to these disorders, which may potentially affect their livelihoods, quality of life, and productivity. The objectives of this review were to describe the different situations encountered in interventional radiology and to compile the strategies both available to date and in development to improve ergonomics.

Contribution of Imaging to Organs at Risk Dose during Lung Stereotactic Body Radiation Therapy.

BACKGROUND: The use of imaging is indispensable in modern radiation therapy, both for simulation and treatment delivery. For safe and sure utilization, dose delivery from imaging must be evaluated. OBJECTIVE: This study aims to investigate the dose to organ at risk (OAR) delivered by imaging during lung stereotactic body radiation therapy (SBRT) and to evaluate its contribution to the treatment total dose. MATERIAL AND METHODS: In this retrospectively study, imaging total dose to organs at risk (OARs) (spinal cord, esophagus, lungs, and heart) and effective dose were retrospectively evaluated from 100 consecutive patients of a single institution who had lung SBRT. For each patient, dose was estimated using Monte-Carlo convolution for helical computed tomography (helical CT), Four-Dimensional CT (4D-CT), and kilovoltage Cone-Beam CT (kV-CBCT). Helical CT and kV-CBCT dose were evaluated for the entire thorax acquisition, while 4D-CT dose was analyzed on upper lobe (UL) or lower lobe (LL) acquisition. Treatment dose was extracted from treatment planning system and compared to imaging total dose. RESULTS: Imaging total dose maximum values were 117 mGy to the spinal cord, 127 mGy to the esophagus, 176 mGy to the lungs and 193 mGy to the heart. The maximum effective dose was 19.65 mSv for helical CT, 10.62 mSv for kV-CBCT, 25.95 mSv and 38.45 mSv for 4D-CT in UL and LL regions, respectively. Depending on OAR, treatment total dose was higher from 1.7 to 8.2 times than imaging total dose. Imaging total dose contributed only to 0.3% of treatment total dose. CONCLUSION: Imaging dose delivered with 4D-CT to the OARs is higher than those of others modalities. The heart received the highest imaging dose for both UL and LL. Total imaging dose is negligible since it contributed only to 0.3% of treatment total dose.

Limiting radiation exposure during prostatic arteries embolization: influence of patient characteristics, anatomical conditions, and technical factors.

OBJECTIVE: To assess the influence of patient characteristics, anatomical conditions, and technical factors on radiation exposure during prostatic arteries embolization (PAE) performed for benign prostatic hyperplasia. MATERIALS AND METHODS: Patient characteristics (age, body mass index (BMI)), anatomical conditions (number of prostatic arteries, anastomosis), and technical factors (use of cone beam computed tomography (CBCT), large display monitor (LDM), and magnification) were recorded as well as total air kerma (AK), dose area product (DAP), fluoroscopy time (FT), and number of acquisitions (NAcq). Associations between potential dose-influencing factors and AK using univariate analysis and a multiple linear regression model were assessed. RESULTS: Forty-one consecutive men (68 ± 8 years, min-max: 40-76) were included. LDM and CBCT decreased the use of small field of view with 13.9 and 3.8% respectively, both p < 0.001. The use of a LDM significantly reduced AK (1006.6 ± 471.7 vs. 1412 ± 754.6 mGy, p = 0.02), DAP (119.4 ± 64.4 vs. 167.9 ± 99.2, p = 0.04), FT (40.4 ± 11.5 vs. 53.6 ± 25.5 min, p = 0.01), and NAcq (16.3 ± 6.3 vs. 18.2 ± 7, p = 0.04). In multivariate analysis, AK reduction was associated with lower patient BMI (ß = 0.359, p = 0.002), shorter FT (ß = 0.664, p < 0.001) and CBCT use (ß = - 0.223, p = 0.03), and decreased NAcq (ß = 0.229, p = 0.04). CONCLUSION: LDM and CBCT are important technical dose-related factors to help reduce radiation exposure during PAE, and should be considered in standard practice. KEY POINTS: • The use of large display monitor (LDM) and cone beam computed tomography (CBCT) both decreased the need for magnification during prostatic arteries embolization (PAE). • The use of LDM reduces radiation exposure during PAE. • Total air kerma is associated with patient's body mass index, fluoroscopy time, CBCT, and the number of acquisitions.

Use of Model-Based Iterative Reconstruction (MBIR) in reduced-dose CT for routine follow-up of patients with malignant lymphoma: dose savings, image quality and phantom study.

OBJECTIVES: To evaluate both in vivo and in phantom studies, dose reduction, and image quality of body CT reconstructed with model-based iterative reconstruction (MBIR), performed during patient follow-ups for lymphoma. METHODS: This study included 40 patients (mean age 49 years) with lymphoma. All underwent reduced-dose CT during follow-up, reconstructed using MBIR or 50 % advanced statistical iterative reconstruction (ASIR). All had previously undergone a standard dose CT with filtered back projection (FBP) reconstruction. The volume CT dose index (CTDIvol), the density measures in liver, spleen, fat, air, and muscle, and the image quality (noise and signal to noise ratio, SNR) (ANOVA) observed using standard or reduced-dose CT were compared both in patients and a phantom study (Catphan 600) (Kruskal Wallis). RESULTS: The CTDIvol was decreased on reduced-dose body CT (4.06 mGy vs. 15.64 mGy p < 0.0001). SNR was higher in reduced-dose CT reconstructed with MBIR than in 50 % ASIR or than standard dose CT with FBP (patients, p ≤ 0.01; phantoms, p = 0.003). Low contrast detectability and spatial resolution in phantoms were not altered on MBIR-reconstructed CT (p ≥ 0.11). CONCLUSION: Reduced-dose CT with MBIR reconstruction can decrease radiation dose delivered to patients with lymphoma, while keeping an image quality similar to that obtained on standard-dose CT. KEY POINTS: • In lymphoma patients, CT dose reduction is a major concern. • Reduced-dose body CT provides a fourfold radiation dose reduction. • Optimized CT reconstruction techniques (MBIR) can maintain image quality.