Motion artifacts occurring at the lung/diaphragm interface using 4D CT attenuation correction of 4D PET scans

For PET/CT, fast CT acquisition time can lead to errors in attenuation correction, particularly at the lung/diaphragm interface. Gated 4D PET can reduce motion artifacts, though residual artifacts may persist depending on the CT dataset used for attenuation correction. We performed phantom studies to evaluate 4D PET images of targets near a density interface using three different methods for attenuation correction: a single 3D CT (3D CTAC), an averaged 4D CT (CINE CTAC), and a fully phase matched 4D CT (4D CTAC). A phantom was designed with two density regions corresponding to diaphragm and lung. An 8 mL sphere phantom loaded with 18F‐FDG was used to represent a lung tumor and background FDG included at an 8:1 ratio. Motion patterns of sin(x) and sin4(x) were used for dynamic studies. Image data was acquired using a GE Discovery DVCT‐PET/CT scanner. Attenuation correction methods were compared based on normalized recovery coefficient (NRC), as well as a novel quantity “fixed activity volume” (FAV) introduced in our report. Image metrics were compared to those determined from a 3D PET scan with no motion present (3D STATIC). Values of FAV and NRC showed significant variation over the motion cycle when corrected by 3D CTAC images. 4D CTAC‐ and CINE CTAC–corrected PET images reduced these motion artifacts. The amount of artifact reduction is greater when the target is surrounded by lower density material and when motion was based on sin4(x). 4D CTAC reduced artifacts more than CINE CTAC for most scenarios. For a target surrounded by water equivalent material, there was no advantage to 4D CTAC over CINE CTAC when using the sin(x) motion pattern. Attenuation correction using both 4D CTAC or CINE CTAC can reduce motion artifacts in regions that include a tissue interface such as the lung/diaphragm border. 4D CTAC is more effective than CINE CTAC at reducing artifacts in some, but not all, scenarios. PACS numbers: 87.57.qp, 87.57.c

Low Incidence of Chest Wall Pain with a Risk-Adapted Lung Stereotactic Body Radiation Therapy Approach Using Three or Five Fractions Based on Chest Wall Dosimetry

Purpose To examine the frequency and potential of dose-volume predictors for chest wall (CW) toxicity (pain and/or rib fracture) for patients receiving lung stereotactic body radiotherapy (SBRT) using treatment planning methods to minimize CW dose and a risk-adapted fractionation scheme. Methods: We reviewed data from 72 treatment plans, from 69 lung SBRT patients with at least one year of follow-up or CW toxicity, who were treated at our center between 2010 and 2013. Treatment plans were optimized to reduce CW dose and patients received a risk-adapted fractionation of 18 Gy×3 fractions (54 Gy total) if the CW V30 was less than 30 mL or 10–12 Gy×5 fractions (50–60 Gy total) otherwise. The association between CW toxicity and patient characteristics, treatment parameters and dose metrics, including biologically equivalent dose, were analyzed using logistic regression. Results: With a median follow-up of 20 months, 6 (8.3%) patients developed CW pain including three (4.2%) grade 1, two (2.8%) grade 2 and one (1.4%) grade 3. Five (6.9%) patients developed rib fractures, one of which was symptomatic. No significant associations between CW toxicity and patient and dosimetric variables were identified on univariate nor multivariate analysis. Conclusions: Optimization of treatment plans to reduce CW dose and a risk-adapted fractionation strategy of three or five fractions based on the CW V30 resulted in a low incidence of CW toxicity. Under these conditions, none of the patient characteristics or dose metrics we examined appeared to be predictive of CW pain

The Use of Research Evidence in Public Health Decision Making Processes: Systematic Review

BACKGROUND: The use of research evidence to underpin public health policy is strongly promoted. However, its implementation has not been straightforward. The objectives of this systematic review were to synthesise empirical evidence on the use of research evidence by public health decision makers in settings with universal health care systems. METHODS: To locate eligible studies, 13 bibliographic databases were screened, organisational websites were scanned, key informants were contacted and bibliographies of included studies were scrutinised. Two reviewers independently assessed studies for inclusion, extracted data and assessed methodological quality. Data were synthesised as a narrative review. FINDINGS: 18 studies were included: 15 qualitative studies, and three surveys. Their methodological quality was mixed. They were set in a range of country and decision making settings. Study participants included 1063 public health decision makers, 72 researchers, and 174 with overlapping roles. Decision making processes varied widely between settings, and were viewed differently by key players. A range of research evidence was accessed. However, there was no reliable evidence on the extent of its use. Its impact was often indirect, competing with other influences. Barriers to the use of research evidence included: decision makers' perceptions of research evidence; the gulf between researchers and decision makers; the culture of decision making; competing influences on decision making; and practical constraints. Suggested (but largely untested) ways of overcoming these barriers included: research targeted at the needs of decision makers; research clearly highlighting key messages; and capacity building. There was little evidence on the role of research evidence in decision making to reduce inequalities. CONCLUSIONS: To more effectively implement research informed public health policy, action is required by decision makers and researchers to address the barriers identified in this systematic review. There is an urgent need for evidence to support the use of research evidence to inform public health decision making to reduce inequalities

Clinical Outcomes Among Patients Treated With Stereotactic Body Radiation Therapy to Femur Metastases for Oligometastatic Disease Control or Reirradiation: Results From a Large Single-Institution Experience

Purpose: There are limited data regarding outcomes after stereotactic body radiation therapy (SBRT) for femur metastases, which was an exclusion criteria for the Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers (SABR-COMET) trial. We aimed to characterize clinical outcomes from a large single institution experience. Methods and Materials: Forty-eight patients with 53 lesions were consecutively treated with femur SBRT from May 2017 to June 2022. The Kaplan-Meier method and Cox proportional hazard models were used to characterize time-to-event endpoints and associations between baseline factors and clinical outcomes, respectively. Local control and locoregional control were defined as the absence of tumor progression within the radiation treatment field or within the treated femur, respectively. Results: Most patients had Eastern Cooperative Oncology Group performance status 0 to 1 (90%), prostate (52%) or breast/lung (17%) cancer, and 1 to 3 lesions (100%), including 29 proximal and 5 distal. Fifty-seven percent of the lesions were treated with concurrent systemic therapy. Median planning target volume was 49.1 cc (range, 6.6-387 cc). Planning target volume V100 (%) was 99% (range, 90-100). Fractionation included 18 to 20 Gy/1F, 27 to 30 Gy/3F, and 28.5-40 Gy/5F. Forty-two percent had Mirels score ≥7 and most (94%) did not have extraosseous extension. Acute toxicities included grade 1 fatigue (15%), pain flare (7.5%), nausea (3.8%), and decreased blood counts (1.9%). Late toxicities included fracture (1.9%) at 1.5 years and osteonecrosis (4%) from dose of 40 Gy in 5F and 30 Gy in 5F (after prior 30 Gy/10F). One patient (2%) required fixation postradiation for progressive pain. With median follow-up 19.4 months, 1- and 2-year rates of local control were 94% and 89%, locoregional control was 83% and 67%, progression-free survival were 56% and 25%, and overall survival were 91% and 73%. Fifty percent of local regional recurrence events occurred within 5 cm of gross tumor volume. Conclusions: Femur SBRT for oligometastatic disease control in well-selected patients was associated with good outcomes with minimal rates of acute and late toxicity. Patterns of local regional recurrence warrant consideration of larger elective volume coverage. Additional prospective study is needed

Chest wall and planning target volume (PTV) contour, in blue and red respectively.

<p>Chest wall and planning target volume (PTV) contour, in blue and red respectively.</p

Incidence of Chest Wall Toxicities for 72 peripheral lung SBRT treatment plans.

<p>*Grade 2 pain.</p

Tumor Characteristics and Dosimetry Metrics.

<p>Tumor Characteristics and Dosimetry Metrics.</p

Comparison of CW toxicity from our study versus previously reported studies.

<p>*Not described in the paper.</p