Color Intensity Projections: A simple way to display changes in astronomical images

To detect changes in repeated astronomical images of the same field of view (FOV), a common practice is to stroboscopically switch between the images. Using this method, objects that are changing in location or intensity between images are easier to see because they are constantly changing. A novel display method, called arrival time color intensity projections (CIPs), is presented that combines any number of grayscale images into a single color image on a pixel by pixel basis. Any values that are unchanged over the grayscale images look the same in the color image. However, pixels that change over the grayscale image have a color saturation that increases with the amount of change and a hue that corresponds to the timing of the changes. Thus objects moving in the grayscale images change from red to green to blue as they move across the color image. Consequently, moving objects are easier to detect and assess on the color image than on the grayscale images. A sequence of images of a comet plunging into the sun taken by the SOHO satellite (NASA/ESA) and Hubble Space Telescope images of a trans-Neptunian object (TNO) are used to demonstrate the method.Comment: 9 pages, 2 figures. Accepted for publication in Publications of the Astronomical Society of the Pacific. The quality of figure 1 been improved from the previous posted versio

Outcomes of Stereotactic Ablative Radiotherapy for Centrally Located Early-Stage Lung Cancer

Introduction:The use of stereotactic ablative radiotherapy (SABR) in centrally located early-stage lung tumors has been associated with increased toxicity. We studied outcomes after delivery of risk-adapted SABR of central tumors.Methods:SABR was delivered in eight fractions of 7.5 Gy to 63 such patients between 2003 and 2009. Of these, 37 patients had a tumor at a central hilar location, whereas 26 patients had tumors abutting the pericardium or mediastinal structures. Survival outcomes were compared with patients with peripheral tumors treated during the same time period using fewer fractions of SABR.Results:Median follow-up was 35 months. Late grade III toxicity was limited to chest wall pain (n = 2) and increased dyspnoea (n = 2). No grade IV/V toxicity was observed, but grade V toxicity could not be excluded with certainty in nine patients who died of cardiopulmonary causes. Distant metastases were the predominant cause of death; cardiovascular deaths were not associated with a paracardial tumor location. No significant differences in outcomes were observed between these 63 patients and 445 other SABR patients treated for peripheral early-stage lung tumors. Three-year local control rates were 92.6% and 90.2% (p = 0.9). Three-year overall survival rates were 64.3% and 51.1% with median survival rates of 47 and 36 months, in favor of the group of patients with central tumors (p = 0.09).Conclusions:Use of risk-adapted SABR delivered in eight fractions of 7.5 Gy did not result in excess toxicity for centrally located early-stage lung tumors, and clinical outcomes were comparable with those seen for peripheral lesions

Patterns of Disease Recurrence after SABR for Early Stage Non–Small-Cell Lung Cancer: Optimizing Follow-Up Schedules for Salvage Therapy

Introduction:Stereotactic ablative radiotherapy is a guideline-recommended treatment for early stage non–small-cell lung cancer. We report on incidence and salvage of local recurrences (LR) and second primary lung cancers (SPLC) in a large series of patients with long-term follow-up, to generate data for evidence-based follow-up regimens.Methods:We excluded all patients with double tumors, TNM-stages other than T1-T2N0M0, biologically effective dose less than 100 Gy10 and previous treatment for the index tumor from our institutional database. LR was defined as recurrence in/adjacent to the planning target volume. A diagnosis of SPLC was determined using criteria described by Martini et al.Results:The 855 patients included had a median follow-up of 52 months. Forty-six patients developed LR after a median of 22 months (range 7–87 months). Actuarial local control rates at 3 and 5 years were 92.4% and 90.9%, respectively. Fifty-four percent had isolated LR and 13% had LR in combination with regional recurrences. Ten patients underwent radical salvage treatment; surgery (N = 6), high-dose radiotherapy (N = 3), or chemoradiation (N = 1). Median overall survival following LR was 13 months, but it was 36 months in patients who underwent radical salvage. A SPLC was diagnosed in 79 patients, after a median interval of 34 months. Actuarial cumulative incidences of SPLC at 3 and 5 years were 11.7% and 16.7%, respectively. Radical salvage for SPLC was performed in 63 patients (80%).Conclusions:Both the timing of LR and persistent risk of SPLC serve as rationale for long-term follow-up using computed tomography scans in patients fit enough to undergo any radical treatment

A dosimetric analysis of respiration-gated radiotherapy in patients with stage III lung cancer

BACKGROUND: Respiration-gated radiotherapy can permit the irradiation of smaller target volumes. 4DCT scans performed for routine treatment were retrospectively analyzed to establish the benefits of gating in stage III non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Gross tumor volumes (GTVs) were contoured in all 10 respiratory phases of a 4DCT scan in 15 patients with stage III NSCLC. Treatment planning was performed using different planning target volumes (PTVs), namely: (i) PTV(routine), derived from a single GTV plus 'conventional' margins; (ii) PTV(all phases )incorporating all 3D mobility captured by the 4DCT; (iii) PTV(gating), incorporating residual 3D mobility in 3–4 phases at end-expiration. Mixed effect models were constructed in order to estimate the reductions in risk of lung toxicity for the different PTVs. RESULTS: Individual GTVs ranged from 41.5 – 235.0 cm(3). With patient-specific mobility data (PTV(all phases)), smaller PTVs were derived than when 'standard' conventional margins were used (p < 0.001). The average residual 3D tumor mobility within the gating window was 4.0 ± 3.5 mm, which was 5.5 mm less than non-gated tumor mobility (p < 0.001). The reductions in mean lung dose were 9.7% and 4.9%, respectively, for PTV(all phases )versus PTV(routine), and PTV(gating )versus PTV(all phases). The corresponding reductions in V(20 )were 9.8% and 7.0%, respectively. Dosimetric gains were smaller for primary tumors of the upper lobe versus other locations (p = 0.02). Respiratory gating also reduced the risks of radiation-induced esophagitis. CONCLUSION: Respiration-gated radiotherapy can reduce the risk of pulmonary toxicity but the benefits are particularly evident for tumors of the middle and lower lobes

Salvage surgery for local failures after stereotactic ablative radiotherapy for early stage non-small cell lung cancer

markdownabstract__Introduction:__ The literature on surgical salvage, i.e. lung resections in patients who develop a local recurrence following stereotactic ablative radiotherapy (SABR), is limited. We describe our experience with salvage surgery in nine patients who developed a local recurrence following SABR for early stage non-small cell lung cancer (NSCLC). __Methods:__ Patients who underwent surgical salvage for a local recurrence following SABR for NSCLC were identified from two Dutch institutional databases. Complications were scored using the Dindo-Clavien-classification. __Results:__ Nine patients who underwent surgery for a local recurrence were identified. Median time to local recurrence was 22 months. Recurrences were diagnosed with CT- and/or 18FDG-PET-imaging, with four patients also having a pre-surgical pathological diagnosis. Extensive adhesions were observed during two resections, requiring conversion from a thoracoscopic procedure to thoracotomy during one of these procedures. Three patients experienced complications post-surgery; grade 2 (N = 2) and grade 3a (N = 1), respectively. All resection specimens showed viable tumor cells. Median length of hospital stay was 8 days (range 5-15 days) and 30-day mortality was 0 %. Lymph node dissection revealed mediastinal metastases in 3 patients, all of whom received adjuvant therapy. __Conclusions:__ Our experience with nine surgical procedures for local recurrences post-SABR revealed two grade IIIa complications, and a 30-day mortality of 0 %, suggesting that salvage surgery can be safely performed after SABR

Revised guideline 'Brain metastases':More treatment options

The guideline on brain metastasis from the Netherlands Society of Neurology has been updated. Important changes have been made, particularly with regard to treatment of brain metastases. Treatment of patients with brain metastases is complex and requires a multidisciplinary approach to formulate an optimal, individualized treatment plan. Neurosurgical resection may also be considered in patients with multiple brain metastases and one dominant, symptomatic lesion, if the patient is in good clinical condition. Stereotactic radiosurgery is a treatment option for patients with a maximum of 10 brain metastases, depending on the size and number of metastases. The indication for whole brain radiotherapy is relatively limited. Doctors should be cautious with whole brain radiotherapy in patients with a Karnofsky Performance Status &lt;70. In patients with small, asymptomatic brain metastases, targeted therapy or immune therapy may be considered without locoregional therapy

ESTRO-EANO guideline on target delineation and radiotherapy details for glioblastoma

BACKGROUND AND PURPOSE Target delineation in glioblastoma is still a matter of extensive research and debate. This guideline aims to update the existing joint European consensus on delineation of the clinical target volume (CTV) in adult glioblastoma patients. MATERIAL AND METHODS The ESTRO Guidelines Committee identified 14 European experts in close interaction with the ESTRO clinical committee and EANO who discussed and analysed the body of evidence concerning contemporary glioblastoma target delineation, then took part in a two-step modified Delphi process to address open questions. RESULTS Several key issues were identified and are discussed including i) pre-treatment steps and immobilisation, ii) target delineation and the use of standard and novel imaging techniques, and iii) technical aspects of treatment including planning techniques and fractionation. Based on the EORTC recommendation focusing on the resection cavity and residual enhancing regions on T1-sequences with the addition of a reduced 15 mm margin, special situations are presented with corresponding potential adaptations depending on the specific clinical situation. CONCLUSIONS The EORTC consensus recommends a single clinical target volume definition based on postoperative contrast-enhanced T1 abnormalities, using isotropic margins without the need to cone down. A PTV margin based on the individual mask system and IGRT procedures available is advised; this should usually be no greater than 3 mm when using IGRT

Individualized early death and long-term survival prediction after stereotactic radiosurgery for brain metastases of non-small cell lung cancer:Two externally validated nomograms

Introduction Commonly used clinical models for survival prediction after stereotactic radiosurgery (SRS) for brain metastases (BMs) are limited by the lack of individual risk scores and disproportionate prognostic groups. In this study, two nomograms were developed to overcome these limitations. Methods 495 patients with BMs of NSCLC treated with SRS for a limited number of BMs in four Dutch radiation oncology centers were identified and divided in a training cohort (n = 214, patients treated in one hospital) and an external validation cohort n = 281, patients treated in three other hospitals). Using the training cohort, nomograms were developed for prediction of early death (<3 months) and long-term survival (>12 months) with prognostic factors for survival. Accuracy of prediction was defined as the area under the curve (AUC) by receiver operating characteristics analysis for prediction of early death and long term survival. The accuracy of the nomograms was also tested in the external validation cohort. Results Prognostic factors for survival were: WHO performance status, presence of extracranial metastases, age, GTV largest BM, and gender. Number of brain metastases and primary tumor control were not prognostic factors for survival. In the external validation cohort, the nomogram predicted early death statistically significantly better (p < 0.05) than the unfavorable groups of the RPA, DS-GPA, GGS, SIR, and Rades 2015 (AUC = 0.70 versus range AUCs = 0.51–0.60 respectively). With an AUC of 0.67, the other nomogram predicted 1 year survival statistically significantly better (p < 0.05) than the favorable groups of four models (range AUCs = 0.57–0.61), except for the SIR (AUC = 0.64, p = 0.34). The models are available on www.predictcancer.org. Conclusion The nomograms predicted early death and long-term survival more accurately than commonly used prognostic scores after SRS for a limited number of BMs of NSCLC. Moreover these nomograms enable individualized probability assessment and are easy into use in routine clinical practice