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OBJECTIVES: The National Council on Radiation Protection (NCRP) report no. 168 recommended that during fluoroscopically guided interventions (FGIs), each patient should be monitored when one of the following thresholds is reached: an air kerma > 5 Gy, a kerma area product (KAP) > 500 Gy.cm2, a fluoroscopy time > 60 min, or a peak skin dose (PSD) > 3 Gy. Whereas PSD is the most accurate metric regarding the prevention of radiological risks, it remains the most difficult parameter to assess. We aimed to evaluate the relevance of the other, more accessible metrics and propose new optimized threshold (OT) for improved patient follow-up. METHODS: Overall, 108 patients who underwent FGI in which at least one NCRP threshold was reached and PSD was measured were considered. The correlation between all metrics was assessed using principal component analysis (PCA). ROC curves and the sensitivity/specificity of both NCRP and OT to predict PSD > 3 Gy were evaluated. RESULTS: The PCA shows that FGI can be decomposed with two components based on time and dose variables. Only KAP and kerma were correlated with PSD. The overall sensitivity and specificity of the new OT regarding KAP (67.6/93.0), kerma (97.3/81.7), and time (62.2/62.0) were better compared with NCRP thresholds (97.3/16.9, 40.5/95.4, and 21.6/74.7). CONCLUSIONS: This study shows that fluoroscopy time is not a relevant metric when used to predict PSDs > 3 Gy. By adapting KAP and kerma thresholds to predict PSD over 3 Gy, patient follow-ups following vascular FGI can be improved. KEY POINTS: ⢠In vascular fluoroscopically guided interventions, principal component analysis demonstrates that between fluoroscopy time, KAP, and kerma, only the two last were correlated to the peak skin dose. ⢠Optimized thresholds replacing NRCP ones obtained with ROC curves analysis were 85,451 µGy.cm2, 2938 mGy, and 41 min for KAP, kerma, and fluoroscopy time respectively. ⢠Improvements to trigger patient follow-up after vascular fluoroscopically guided interventions may be obtained by using the optimized thresholds.
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Protección Radiológica , Radiografía Intervencional , Fluoroscopía , Humanos , Dosis de Radiación , RadiometríaRESUMEN
The original version of this article, published on 02 May 2020, unfortunately contained a mistake.
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OBJECTIVES: To establish national reference levels (RLs) in interventional procedures under CT guidance as required by the 2013/59/Euratom European Directive. METHODS: Seventeen categories of interventional procedures in thoracic, abdominopelvic, and osteoarticular specialties (percutaneous infiltration, vertebroplasty, biopsy, drainage, tumor destruction) were analyzed. Total dose length product (DLP), number of helical acquisitions (NH), and total DLP for helical, sequential, or fluoroscopic acquisitions were recorded for 10 to 20 patients per procedure at each center. RLs were calculated as the 3rd quartiles of the distributions and target values for optimization process (TVOs) as the median. RLs and TVOs were compared with previously published studies. RESULTS: Results on 5001 procedures from 49 centers confirmed the great variability in patient dose for the same category of procedures. RLs were proposed for the DLPs and NHs in the seventeen categories. RLs in terms of DLP and NH were 375 mGy.cm and 2 NH for spinal or peri-spinal infiltration, 1630 mGy.cm and 3 NH for vertebroplasty, 845 mGy.cm and 4 NH for biopsy, 1950 mGy.cm and 8 NH for destruction of tumors, and 1090 mGy.cm and 5 NH for drainage. DLP and NH increased with the complexity of procedures. CONCLUSIONS: This study was the first nationwide multicentric survey to propose RLs for interventional procedures under CT guidance. Heterogeneity of practice in centers were found with different levels of patient doses for the same procedure. The proposed RLs will allow imaging departments to benchmark their practice with others and optimize their protocols. KEY POINTS: ⢠National reference levels are proposed for 17 categories of interventional procedures under CT guidance. ⢠Reference levels are useful for benchmarking practices and optimizing protocols. ⢠Reference levels are proposed for dose length product and the number of helical acquisitions.
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Dosis de Radiación , Radiografía Intervencional/normas , Valores de Referencia , Tomografía Computarizada por Rayos X/normas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Femenino , Fluoroscopía/métodos , Francia , Humanos , Masculino , Persona de Mediana Edad , Radiografía Intervencional/métodos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Columna Vertebral , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X/métodos , Vertebroplastia , Adulto JovenRESUMEN
The Triple-Negative Breast Cancer subtype (TNBC) is particularly aggressive and heterogeneous. Thus, Poly-ADP-Ribose Polymerase inhibitors were developed to improve the prognosis of patients and treatment protocols are still being evaluated. In this context, we modelized the efficacy of Olaparib (i.e., 5 and 50 µM), combined with fractioned irradiation (i.e., 5 × 2 Gy) on two aggressive TNBC cell lines MDA-MB-231 (BRCAness) and SUM1315 (BRCA1-mutated). In 2D cell culture and for both models, the clonogenicity drop was 95-fold higher after 5 µM Olaparib and 10 Gy irradiation than Olaparib treatment alone and was only 2-fold higher after 50 µM and 10 Gy. Similar responses were obtained on TNBC tumor-like spheroid models after 10 days of co-treatment. Indeed, the ratio of metabolic activity decrease was of 1.2 for SUM1315 and 3.3 for MDA-MB-231 after 5 µM and 10 Gy and of only 0.9 (both models) after 50 µM and 10 Gy. MDA-MB-231, exhibiting a strong proliferation profile and an overexpression of AURKA, was more sensitive to the co-treatment than SUM1315 cell line, with a stem-cell like phenotype. These results suggest that, with the studied models, the potentiation of Olaparib treatment could be reached with low-dose and long-term exposure combined with fractioned irradiation.
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In the present study, we have evaluated the efficacy and toxicity of repeated brain metastases (BM) stereotactic radiosurgery (SRS2) following local failure of a prior radiosurgical procedure (SRS1). Between December 1996 and August 2015, 30 patients with 36 BM underwent SRS2 with a median dose of 18Gy. All BM were located outside critical structures. Following SRS2, local control at 6 months and one year were respectively 82.9% (IC 95%: 67.6-91.9) and 67.8% (IC 95%: 51-81). On multivariate analysis, planning target volume (PTV) < 3cc (HR: 0.19 (0.1-0.52)) and whole brain radiotherapy (WBRT) prior to SRS2 (HR: 0.25 (0.1-0.64)) were significantly associated with a better local control. One- and two-year overall survival rates after SRS2 were respectively 65.5% (IC 95%: 47.3-80%) and 27.6% (IC 95%: 14.7-45.7). Median overall survival following SRS2 was 14.2 months (range 1-106). Nineteen (63%) patients died from progressive systemic disease. Three (10%) patients died from out-field progressive brain disease and 8 (27%) in-field. Concerning toxicities, edema, radionecrosis, and hemorrhages were identified in 5 (12.8%), 4 (10.2%), and 5 (12.8%) patients respectively. No toxicity resulted in a neurological deficit. On univariate analysis, toxicities were significantly associated with PTV > 7cc (p = 0.02) and all patients had a WBRT before SRS2. A second course of SRS for locally recurrent brain metastases showed encouraging rates of local control. This treatment led to acceptable toxicities, especially for brain metastases smaller than 7cc, in our selected cohort of patients with BM located outside critical structures. Further studies are needed.
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Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundario , Recurrencia Local de Neoplasia/radioterapia , Radiocirugia , Reirradiación , Terapia Recuperativa , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/mortalidad , Irradiación Craneana/efectos adversos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Recurrencia Local de Neoplasia/diagnóstico por imagen , Recurrencia Local de Neoplasia/mortalidad , Radiocirugia/efectos adversos , Planificación de la Radioterapia Asistida por Computador , Reirradiación/efectos adversos , Terapia Recuperativa/efectos adversos , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
PURPOSE: To compare, in an interventional radiology setting, peak skin doses (PSDs) delivered as calculated using a dedicated software tool and as measured using radiochromic film. To assess the utility of this dose calculation software tool in routine clinical practice. MATERIALS AND METHODS: First, radiochromic films were positioned on the examination table in the back of an adult anthropomorphic phantom to measure PSD, and X-ray examinations were simulated. Then, films were again positioned in the patient's back for 59 thoracic or abdominopelvic endovascular interventions. The results obtained with the radiochromic films were taken as a reference and were statistically compared with those of the software. RESULTS: With measured PSDs ranging from 100 to 7000 mGy, the median software-film difference was 8.5%. Lin's concordance coefficient was 0.98 [0.97; 0.99] (p < 0.001), meaning that concordance was excellent between the two methods. For the films where PSD exceeded 1000 mGy, the median difference in the measured value was 8.7% [- 1.3; 21.1], with a maximum discrepancy of 34%. Lin's concordance coefficient was 0.98 [0.96; 1] (p < 0.001), meaning that concordance was excellent between the two methods. CONCLUSION: Comparison between radiochromic films and the software tool showed that the software is a suitable tool for a simple and reliable estimation of PSD. The software seems to be a good alternative to films, whose use remains complex.
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Dosimetría por Película/instrumentación , Fantasmas de Imagen , Dosis de Radiación , Dosimetría por Película/métodos , Humanos , Piel , Programas InformáticosRESUMEN
BACKGROUND: Benign tumors of the skull base are a challenge when delivering radiotherapy. An appropriate choice of radiation technique may significantly improve the patient's outcomes. Our study aimed to compare the dosimetric results of fractionated stereotactic radiotherapy between non-coplanar dynamic arcs and coplanar volumetric modulated arctherapy (Rapidarc®). METHODS: Thirteen patients treated with Novalis TX® were analysed: six vestibular schwannomas, four pituitary adenomas and three meningioma. Two treatment plans were created for each case: dynamic arcs (4-5 non coplanar arcs) and Rapidarc® (2 coplanar arcs). All tumors were >3 cm and accessible to both techniques. Patients had a stereotactic facemask (Brainlab) and were daily repositioned by Exactrac®. GTV and CTV were contoured according to tumor type. A 1-mm margin was added to the CTV to obtain PTV. Radiation doses were 52.2-54 Gy, using 1.8 Gy per fraction. Treatment time was faster with Rapidarc®. RESULTS: The mean PTV V95 % was 98.8 for Rapidarc® and 95.9 % for DA (p = 0.09). Homogeneity index was better with Rapidarc®: 0.06 vs. 0.09 (p = 0.01). Higher conformity index values were obtained with Rapidarc®: 75.2 vs. 67.9 % (p = 0.04). The volume of healthy brain that received a high dose (V90 %) was 0.7 % using Rapidarc® vs. 1.4 % with dynamic arcs (p = 0.05). Rapidarc® and dynamic arcs gave, respectively, a mean D40 % of 10.5 vs. 18.1 Gy (p = 0.005) for the hippocampus and a Dmean of 25.4 vs. 35.3 Gy (p = 0.008) for the ipsilateral cochlea. Low-dose delivery with Rapidarc® and dynamic arcs were, respectively, 184 vs. 166 cm(3) for V20 Gy (p = 0.14) and 1265 vs. 1056 cm(3) for V5 Gy (p = 0.67). CONCLUSIONS: Fractionated stereotactic radiotherapy using Rapidarc® for large benign tumors of the skull base provided target volume coverage that was at least equal to that of dynamics arcs, with better conformity and homogeneity and faster treatment time. Rapidarc® also offered better sparing of the ipsilateral cochlea and hippocampus. Low-dose delivery were similar between both techniques.