Dosimetric accuracy of tomotherapy dose calculation in thorax lesions

<p>Abstract</p> <p>Background</p> <p>To analyse limits and capabilities in dose calculation of collapsed-cone-convolution (CCC) algorithm implemented in helical tomotherapy (HT) treatment planning system for thorax lesions.</p> <p>Methods</p> <p>The agreement between measured and calculated dose was verified both in homogeneous (Cheese Phantom) and in a custom-made inhomogeneous phantom. The inhomogeneous phantom was employed to mimic a patient's thorax region with lung density encountered in extreme cases and acrylic inserts of various dimensions and positions inside the lung cavity. For both phantoms, different lung treatment plans (single or multiple metastases and targets in the mediastinum) using HT technique were simulated and verified. Point and planar dose measurements, both with radiographic extended-dose-range (EDR2) and radiochromic external-beam-therapy (EBT2) films, were performed. Absolute point dose measurements, dose profile comparisons and quantitative analysis of gamma function distributions were analyzed.</p> <p>Results</p> <p>An excellent agreement between measured and calculated dose distributions was found in homogeneous media, both for point and planar dose measurements. Absolute dose deviations <3% were found for all considered measurement points, both inside the PTV and in critical structures. Very good results were also found for planar dose distribution comparisons, where at least 96% of all points satisfied the gamma acceptance criteria (3%-3 mm), both for EDR2 and for EBT2 films. Acceptable results were also reported for the inhomogeneous phantom. Similar point dose deviations were found with slightly worse agreement for the planar dose distribution comparison: 96% of all points passed the gamma analysis test with acceptable levels of 4%-4 mm and 5%-4 mm, for EDR2 and EBT2 films respectively. Lower accuracy was observed in high dose/low density regions, where CCC seems to overestimate the measured dose around 4-5%.</p> <p>Conclusions</p> <p>Very acceptable accuracy was found for complex lung treatment plans calculated with CCC algorithm implemented in the tomotherapy TPS even in the heterogeneous phantom with very low lung-density.</p

Use of Vitamin D and Its Metabolites in Broiler Chicken Feed on Performance, Bone Parameters and Meat Quality

The objective of this experiment was to assess the use of different vitamin D metabolites in the feed of broiler chickens and the effects of the metabolites on performance, bone parameters and meat quality. A total of 952 one-day-old male broiler chicks were distributed in a completely randomised design, with four treatments, seven replicates and 34 birds per experimental unit. The treatments consisted of four different sources of vitamin D included in the diet, D3, 25(OH)D3, 1,25(OH)2D3, and 1α(OH)D3, providing 2000 and 1600 IU of vitamin D in the starter (1 to 21 d) and growth phases (22 to 42 d), respectively. Mean weight, feed:gain and weight gain throughout the rearing period were less in animals fed 1α(OH)D3 when compared with the other treatments (p0.05) for various bone parameters. Meat colour differed among the treatments (p>0.05). All of the metabolites used in the diets, with the exception of 1α(OH)D3, can be used for broiler chickens without problems for performance and bone quality, however, some aspects of meat quality were affected

A straightforward multiparametric quality control protocol for proton magnetic resonance spectroscopy: Validation and comparison of various 1.5 T and 3 T clinical scanner systems

Purpose: The aim of this study was to propose and validate across various clinical scanner systems a straightforward multiparametric quality assurance procedure for proton magnetic resonance spectroscopy (MRS). Methods: Eighteen clinical 1.5 T and 3 T scanner systems for MRS, from 16 centres and 3 different manufacturers, were enrolled in the study. A standard spherical water phantom was employed by all centres. The acquisition protocol included 3 sets of single (isotropic) voxel (size 20 mm) PRESS acquisitions with unsuppressed water signal and acquisition voxel position at isocenter as well as off-center, repeated 4/5 times within approximately 2 months. Water peak linewidth (LW) and area under the water peak (AP) were estimated. Results: LW values [mean (standard deviation)] were 1.4 (1.0) Hz and 0.8 (0.3) Hz for 3 T and 1.5 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficient of variation of LW and AP for different spatial positions of acquisition voxel were 43% (20%) and 11% (11%), respectively. The mean (standard deviation) phantom T2 values were 1145 (50) ms and 1010 (95) ms for 1.5 T and 3 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficients of variation for repeated measurements of LW, AP and T2 were 25% (20%), 10% (14%) and 5% (2%), respectively. Conclusions: We proposed a straightforward multiparametric and not time consuming quality control protocol for MRS, which can be included in routine and periodic quality assurance procedures. The protocol has been validated and proven to be feasible in a multicentre comparison study of a fairly large number of clinical 1.5 T and 3 T scanner systems

Low dose rate brachytherapy (LDR-BT) as monotherapy for early stage prostate cancer in Italy: practice and outcome analysis in a series of 2237 patients from 11 institutions

OBJECTIVE: Low-dose-rate brachytherapy (LDR-BT) in localized prostate cancer is available since 15 years in Italy. We realized the first national multicentre and multidisciplinary data collection to evaluate LDR-BT practice, given as monotherapy, and outcome in terms of biochemical failure. METHODS: Between May 1998 and December 2011, 2237 patients with early-stage prostate cancer from 11 Italian community and academic hospitals were treated with iodine-125 ((125)I) or palladium-103 LDR-BT as monotherapy and followed up for at least 2 years. (125)I seeds were implanted in 97.7% of the patients: the mean dose received by 90% of target volume was 145 Gy; the mean target volume receiving 100% of prescribed dose (V100) was 91.1%. Biochemical failure-free survival (BFFS), disease-specific survival (DSS) and overall survival (OS) were estimated using Kaplan-Meier method. Log-rank test and multivariable Cox regression were used to evaluate the relationship of covariates with outcomes. RESULTS: Median follow-up time was 65 months. 5- and 7-year DSS, OS and BFFS were 99 and 98%, 94 and 89%, and 92 and 88%, respectively. At multivariate analysis, the National Comprehensive Cancer Network score (p < 0.0001) and V100 (p = 0.09) were correlated with BFFS, with V100 effect significantly different between patients at low risk and those at intermediate/high risk (p = 0.04). Short follow-up and lack of toxicity data represent the main limitations for a global evaluation of LDR-BT. CONCLUSION: This first multicentre Italian report confirms LDR-BT as an excellent curative modality for low-/intermediate-risk prostate cancer. ADVANCES IN KNOWLEDGE: Multidisciplinary teams may help to select adequately patients to be treated with brachytherapy, with a direct impact on the implant quality and, possibly, on outcome

Organ preservation surgery for low- and intermediate-grade laryngeal chondrosarcomas: Analysis of 16 cases

To demonstrate that endoscopic resection (ER), open partial laryngectomies, and cricotracheal resection and anastomosis (CTRA) achieve a good balance between oncologic radicality and organ preservation for laryngeal low-grade chondrosarcoma (LCS) and intermediate-grade chondrosarcoma (ICS).Retrospective series in an academic institution.Between 2001 and 2013, we treated 13 cricoid, two thyroid, and one arytenoid LCS and ICS. Two cricoid and the only arytenoid LCS were managed by ER. Two thyroid ala LCS were submitted to laminectomy. Five ICS and six LCS of the cricoid received CTRA.Nine patients only required tracheotomy, removed after a maximum of 14 days. Three patients required a nasogastric feeding tube, removed after a maximum of 8 days. Immediate complications included one bleeding, one cervical emphysema, and one partial anastomotic dehiscence. The only late complication was anastomotic stenosis that was resolved by laser resection. All patients regained regular oral feeding and a voice ranging from normal to moderate dysphonia. At the last follow-up, two patients died of unrelated causes, seven are alive with asymptomatic and radiologically stable residual disease, and seven are alive without evidence of persistent disease. One patient received total laryngectomy 11 years after CTRA for recurrent symptomatic disease.Organ preservation surgery for laryngeal LCS and ICS represents a treatment option with low morbidity, good quality of life, and fair possibility to obtain oncologic radicality.4 Laryngoscope, 2013

Function preservation using transoral laser surgery for T2-T3 glottic cancer: oncologic, vocal, and swallowing outcomes

Aim of this study was to retrospectively analyze oncologic and functional results of a cohort of T2 and selected T3 glottic tumors treated by transoral laser surgery (TLS). Eighty-nine patients affected by T2 and T3 glottic tumors were treated by TLS from 2005 to 2010 at an academic institution by Type V cordectomies using an "en bloc" or, more frequently, a "piece-meal" technique depending on a number of variables. Kaplan-Meier curves were used to evaluate 5-year overall, disease-specific survivals, local control with laser, and organ preservation rates. Univariate analysis of the impact of different variables was performed. At least 1 year after surgery, we examined: subjective voice evaluation by voice handicap index (VHI), perceptive analysis by GRBAS scale, objective measurements with multidimensional voice program (MDVP), swallowing assessment with the M.D. Anderson Dysphagia Inventory (MDADI), videonasal endoscopic evaluation of swallowing (VEES), and videofluoroscopy (VFS). Fifty-nine patients were pT2 and 30 pT3. The 5-year overall, disease-specific survivals, local control with laser, and organ preservation rates were 92.4, 98.7, 68.5, and 82.1 %, respectively. VHI mean score was 20 (mild dysphonia). Mild and moderate dysphonias were detected by GRBAS in 82 and 18 % of patients, respectively. Mean values of Jitter, Shimmer, and noise-to-harmonic ratio by MDVP resulted 7.87 %, 24.8 %, and 0.37, respectively. Mean value of MDADI was 95.75. Only 2 % of patients at VEES and 4 % at VFS showed tracheal aspiration. Our results highlight that T2 and selected T3 glottic tumors treated by TLS have favorable oncologic and functional outcomes