-
[show abstract]
[hide abstract]
ABSTRACT: To quantify the changes in dose as well as in the prediction of parotid gland toxicity due to anatomical changes during therapy of head and neck cancer patients.
Fifteen patients with advanced locoregional head and neck cancer, with no evidence of distant metastasis, were enrolled in a prospective study. All patients were treated with intensity-modulated radiotherapy. Multiple computed tomography scans were repeated at the end of each treatment week. The original treatment plans were copied to the per-treatment scans to create hybrid plans. The normal tissue complication probability (NTCP) was calculated assuming the end point to be grade ≥3 xerostomia according to the Radiation Therapy Oncology Group late toxicity scale.
The gross tumour volume dose coverage was slightly affected by the anatomical changes, whereas the mean dose (D(mean)) to the parotids changed from 26.1 ± 6.0 to 27.4 ± 7.4 Gy, with a mean increase of 0.22 Gy/treatment week. Consequently, the mean NTCP increased from 0.15 ± 0.06 to 0.18 ± 0.10, primarily due to a few patients exhibiting a marked increase. The absolute gross tumour volume shrinkage and the percentage parotids shrinkage were the best independent predictors for the NTCP variations.
On average, the increase in the parotids D(mean) as well as in NTCP during treatment is limited, and the observed variations were strongly patient-dependent.
Clinical Oncology 12/2011; 24(3):e54-62. · 2.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study was to develop a quantitative method for breast cancer diagnosis based on elastosonography images in order to reduce whenever possible unnecessary biopsies. The proposed method was validated by correlating the results of quantitative analysis with the diagnosis assessed by histopathologic exam.
109 images of breast lesions (50 benign and 59 malignant) were acquired with the traditional B-mode technique and with elastographic modality. Images in Digital Imaging and COmmunications in Medicine format (DICOM) were exported into a software, written in Visual Basic, especially developed to perform this study. The lesion was contoured and the mean grey value and softness inside the region of interest (ROI) were calculated. The correlations between variables were investigated and receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of the proposed method. Pathologic results were used as standard reference.
Both the mean grey value and the softness inside the ROI resulted statistically different at the t test for the two populations of lesions (i.e., benign versus malignant): p<0.0001. The area under the curve (AUC) was 0.924 (0.834-0.973) and 0.917 (0.826-0.970) for the mean grey value and for the softness respectively.
Quantitative elastosonography is a promising ultrasound technique in the detection of breast cancer but large prospective trials are necessary to determine whether quantitative analysis of images can help to overcome some pitfalls of the methodic.
European journal of radiology 04/2011; 81(7):1527-31. · 2.65 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Purpose: To correlate results of quantitative analysis of real time elastography images (RTEI) with ascerted diagnosis to discriminate malignant from benign breast lesions. Method and Materials: More than 100 images of women (median age 52 yrs) were analyzed in this study. Images in DICOM format were exported into a home‐made software written in Visual Basic especially developed. A pixel by pixel substraction of B‐mode images from color elasticity images was performed. The matrix of RGB values obtained from subtraction was transformed into a matrix of tone of grey (whose values vary from 0 to 255). The regions of interest (ROIs) were delineated and the color spectrum and the parameters of interest (mean value, standard deviation and softness) were calculated for each lesion. Diagnosis (gold‐standard) was assessed by an expert radiologist on the basis of conventional B‐mode US and/or mammography and in some cases by cytophatologic analysis. ROC analysis was used to assess sensitivity and specificity of quantitative approach. Results: The mean values, the standard deviation and softness calculated inside the ROIs resulted statistically different at the t test (p=0.0015, p= 0.0144 and p< 0.0001, respectively) between malignant and benign lesions. The shape and distribution of the color spectrum inside the ROIs resulted statistically different (p< 0.0001, Mann‐Whitney test) between malignant and benign lesions. The ROC analysis for the mean and the softness inside the ROIs indicated sensitivity of 95.6% and 84.4% and specificity of 30.6% and 69.4%, respectively. The area under the curve resulted 0.690 (p=0.0016) and 0.856 (p<0.0001) for the mean and the softness inside the ROIs respectively. Conclusion: Quantitative analysis of RTEI might play an important role in the assessment of the malignancy of breast lesions with the potential to reduce unecessary biopsis. Conflict of Interest: The authors hereby disclose any conflict of interest.
Medical Physics 05/2010; 37(6):3405-3405. · 2.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The purpose of this work is to introduce a new treatment approach and technique for partial breast irradiation in only one session to patients in prone position by using a dedicated positioning device. The patients were treated on a home-made treatment table top that allows the breast to hang down. A particular immobilization system was introduced in order to assure the reproducibility of patient positioning between the CT acquisition session and the treatment session. The clinical target volume (CTV) was outlined according to surgical clips position and/or tumor location on preoperative mammography. Because of negligible movement due to respiration, only an additional margin of 3 mm was added to obtain the planning target volume (PTV). Based on radiobiological calculations, a dose of 21 Gy was prescribed to PTV. The tumor bed was treated with 3D-CRT technique by using 5 fields and rotating the table while the gantry was approximately 90 or 270 degrees. Thirty patients were enrolled for this study chosen in conformity to an approved clinical protocol. The average percentage of PTV volume enclosed in the 90% and 95% of prescribed dose were 99.9 and 98.6% respectively, while only 3.4% of PTV volume received more than 105% of prescribed dose. Dose to 3% of skin volume was, on average, 15.2 Gy. In 97% of patients, less than 50% of the ipsilateral breast received a dose greater than half the prescribed dose. Mean doses to lungs, heart and contralateral breast were negligible. With a median follow-up of 9 months, no important early toxicity was observed both for skin and breast tissue. The treatment of breast tumor bed in prone position in only one session by using the 3D-CRT is technically feasible and seems to be a promising alternative to other accelerated partial breast irradiation techniques.
Journal of experimental & clinical cancer research: CR 01/2008; 26(4):543-52. · 1.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Intensity-modulated radiotherapy (IMRT) (1) is an advanced form of 3-D conformal radiotherapy. It uses non uniform spatial modifications in the intensity of the beams across the irradiated field. Consequently, it is necessary to develop sophisticated tools to compare measured and calculated dose distributions in order to verify the accuracy of the results of the planned dose distribution. Different methods have been developed to evaluate the accordance between measured and calculated doses, such as the point-to-point dose difference or the evaluation of the distance between two closed points having the same dose value (2-4). The verification method proposed by Low (5-7) seems to be more complete since it takes into account both the dose difference (DD) and the distance to agreement (DTA), allowing to define a "score", the gamma value, at each point of interest. A software tool (DDE: Dose Distribution Evaluator), based on Low's method, to evaluate the agreement between dose distribution matrices has been implemented. In particular, the proposed gamma curve, as a function of the isodose levels, gives real-time information useful for decision making about the treatment plan. The paper describes the software, and reports the obtained results in a simple geometry and in several clinical cases (head-neck and prostate). Comparison between measured data (film and MapCheck) and calculated data (CadPlan) using DDE has shown very good agreements. Thanks to its higher resolution, film dosimetry showed better accuracy than the MapCheck technique. Similar results can be obtained also with the MapCheck technique when proper measurement methods are used.
Journal of experimental & clinical cancer research: CR 07/2006; 25(2):229-34. · 1.50 Impact Factor
-
Radiotherapy and Oncology. 01/2005; 76:S174-S174.
-
MMW Fortschritte der Medizin 05/2004; 146(16):65, 67.
-
Radiotherapy and Oncology. 01/2004; 73:S342-S343.
-
[show abstract]
[hide abstract]
ABSTRACT: Dihydropyridines (DHPs), synthetic molecules used as antihypertensive agents, bind to plasma membrane receptors following diffusion through the hydrophobic phase. In this study, MRS technique has been used to clarify the interactions of the dihydrophyridines Nifedipine and Lacidipine within the lipid bilayer. 1D and 2D 1H MRS at high field have been employed to examine the behavior of unilamellar dimyristoyl-phosphatidylcholine liposomes when the two drugs have been inserted in the bilayer. In particular, the study represents an innovative application of 2D 1H NOESY technique to clarify different mechanisms of interactions of small molecules inside model membranes. On the other hand, 31P measurements have been performed in multilamellar dimyristoyl-phosphatidylcholine lipsomes to detect alterations of lipid polymorphic phases. The experiments show that the two dihydropyridines interact with the lipids by different modalities. Lacidipine undergoes a very strong interaction with lipids, possibly inducing a phase segregation of lipid molecules into the bilayer, while self-association seems to be the prevalent interaction of Nifedipine inside the bilayer.
Physiological chemistry and physics and medical NMR 02/2003; 35(1):55-72.
-
[show abstract]
[hide abstract]
ABSTRACT: Intensity modulated radiation therapy (IMRT) is one of the most innovative techniques in oncological radiotherapy, allowing to conform the dose delivery to the tumoral target, preserving the normal tissue. The high number of parameters involved in the IMRT treatment planning requires an automated approach to the beam modulation. Such optimization process consists in the search of the global minimum of a cost function representing a quality index for the treatment. The complexity of this task, has been analyzed with a statistical approach for three clinical cases of particular interest in IMRT. Our main result is that a cost function based on dose-volume constraints entails lower complexity of the optimization process, in terms of the choice of the parameters defining the cost function and in a smaller sensitivity to the initial conditions for the optimization algorithm.
Annali dell'Istituto superiore di sanita 02/2001; 37(2):225-30. · 0.94 Impact Factor
