Clinical Implementation of Weak Magnetic Field Generator in Radiation Therapy

PURPOSE/OBJECTIVE(S)

The application of weak magnetic fields may improve radiation therapy efficacy by manipulating the free radical activity induced by radiation to optimize tumor death. Once the device is commercially available, we will conduct clinical trials to determine the clinical impact of the weak magnetic field. However, the magnetic field generator (MFG) restricts Linac gantry rotation to approximately 180° and this limitation may limit treatment plan quality. This work is a continuation of an ongoing study to determine if the gantry angle restrictions can be compensated for during treatment planning.

MATERIALS/METHODS

Previous work has demonstrated the feasibility for GBM cases. For this work, 10 prostate cancer treatment plans were retrospectively replanned using only coplanar arcs that spanned from 90° to 270° (half-arcs). The prescriptions were 60 Gy for 6 patients, 55.8 Gy for 2 patients, 54 Gy for 1 patient, and 40.05 Gy for 1 patient. The prescription doses were delivered to 95% of the planning target volume (PTV = GTV + 2 cm). The critical structure doses were compared to determine if clinically equivalent plans could be delivered using half-arcs.

RESULTS

The dose criteria that were met by the clinical plans were also met by the half-arc plans except for the cases shown in Table 1. Table 1: Doses that did not meet criteria CONCLUSION: The half-arc plans were able to deliver clinically equivalent dose distributions as the clinical treatment plans. This provides continuing evidence that clinical trials will be able to be developed to evaluate the use of weak magnetic fields for radiation therapy.

Potential Dosimetric Predictors of Patient-Reported Quality of Life for Head and Neck Cancer Following Chemoradiation IMRT

PURPOSE/OBJECTIVE(S)

This study aims to identify both acute and late patient patient-reported salivary quality of life outcomes in patients with head and neck cancer treated with chemoradiation therapy on a prospective trial.

MATERIALS/METHODS

A cohort of 40 patients with head and neck cancers were included in the study. All patients underwent concurrent chemoradiation therapy using IMRT delivery (1 patient on one Linac, 24 patients on a different Linac, and 15 on a helical delivery machine). All patients were asked to complete the University of Washington Quality of Life (UOW-QOL) questionnaire at baseline, immediately after treatment, as well as at 1 month, 3 months, 6 months, 12 month and 18 months post-treatment. For the salivary quality of life (QOL) outcome scores, the possible responses were scored on a discreet scale of 100, 70, 30, and 0, with 100 as normal and 0 as dysfunctional. Dosimetric endpoints achieved based on the treatment plan, such as maximum/mean/minimum doses, V30 (percent volume receiving 30 Gy dose), and Dy (dose received to y percent volume) were collected for the bilateral salivary glands, bilateral temporomandibular joint and bilateral submandibular glands. The associations between these dosimetric parameters and the corresponding salivary QOL scores at each time point were analyzed. A Wilcoxon test was performed to identify any differences in the dosimetry and salivary QOL scores among the four different responses.

RESULTS

At short-term follow-up including 1- and 6-month, the distribution of the mean dose received by the right parotid was significantly different between the patients that reported a salivary QOL score of 30 and those that reported 100, with p-values of 0.007 for the 1-month comparison and 0.006 for the 6-month comparison. This was also seen for the V30, with p-values of 0.027 for the 1-month comparison and 0.013 for the 6-month comparison. At 3 months, the maximum dose received by the left temporomandibular joint was significantly different between the patients that reported 30 and those that reported 70, with a p-value of 0.038. At 6 months, the average dose distribution of the right submandibular gland received between the patients that reported a score of 30 and 100 was also significantly different, with a p-value of 0.006. At the long-term follow-up time points of 12 and 18 months, no significant differences were found.

CONCLUSION

The significant differences seen in the data suggest that the dosimetry may have effects on patient reported salivary QOL at short-term follow-up but not long-term. This provides a new perspective into how a patient's QOL over a period of time could be affected by the amount of dose to critical organs. These results also serve as the basis for further investigation into the actual delivered dose, which could differ from the planned dose due to daily anatomic changes over the course of head and neck radiotherapy delivery. These daily volumetric and dosimetric changes may guide early adaptive treatment to improve patient-reported QOL outcomes.

Validation of a Fast-Helical Free-Breathing CT-Based Ventilation Technique Using Ventilation/Perfusion SPECT Imaging

PURPOSE/OBJECTIVE(S)

In radiotherapy, the lung is considered one homogenous organ at risk during planning. However, avoiding dose to functional lung could help preserve lung function after treatment. This could be possible with ventilation mapping, which is traditionally done with SPECT imaging. Having an accurate, CT-based approach could allow for ventilation mapping within the radiotherapy workflow. In this study, we aim to compare a novel, CT-based ventilation mapping approach to SPECT-based ventilation images.

MATERIALS/METHODS

We acquired both CT-based and SPECT-based ventilation scans for one patient. For the SPECT-based images, the patient inhaled 8.8 mCi Tc-99m DTPA aerosol before scan acquisition with a dual headed SPECT/CT. For the CT-based approach, we acquired 25 fast-helical free-breathing CTs as part of our 5DCT protocol with simultaneous monitoring of the breathing pattern using a respiratory bellows surrogate. We chose one scan as the reference scan, and deformably registered the other 24 scans to it. The Jacobian expansion of each registration was calculated for each voxel and linearly related to the bellows amplitude. The slope of the linear fit, dJ/dA, represented the ventilation for each voxel. To compare the resulting ventilation maps from each method, we first calculated the normalized cross-correlation (NCC) and Spearman correlation coefficient. We also created masks of ventilation greater than various thresholds to see how we could accurately define high and low functioning lung. For example, greater than 50th percentile ventilation being 1 (high functioning) and less than 50th percentile being 0 (low functioning). We calculated Dice scores to compare these threshold masks between the CT-based and SPECT-based ventilation images.

RESULTS

The NCC between the ventilation images was 0.810, and the Spearman correlation between them was 0.587. When comparing volumes of ventilation greater than 50th percentile, the Dice score was 0.730. However, when the threshold was increased, the Dice scores were reduced. Qualitatively, we noted that the lobar ventilation agreed in general, but there was more detail throughout the CT-based image, as opposed to the more precisely defined, high ventilating areas in the SPECT image.

CONCLUSION

We were able to compare our novel, CT-based ventilation approach against a more conventional technique in ventilation SPECT imaging. The resulting ventilation images were qualitatively similar. Analyzing different thresholds showed that we can reasonably separate high and low functioning tissue into greater than or less than 50th percentile ventilation, respectively. In future work, we will aim to expand this study over a larger cohort of patients and also examine longitudinal changes to ventilation after SBRT and lung brachytherapy.

Microsatellite and AFLP markers in the Prunus persica [L. (Batsch)]xP. ferganensis BC(1)linkage map: saturation and coverage improvement

A set of 146 single sequence repeats (SSRs) and 14 amplified fragment length polymorphism (AFLP) primer combinations were used to enrich a previously developed linkage map obtained from a (Prunus persicaxP. ferganensis)xP. persica BC(1) progeny. Forty-one SSR primer pairs gave polymorphic patterns detecting 42 loci. The restriction/selective primer AFLP combinations produced a total of 79 segregating fragments. The resulting map is composed of 216 loci covering 665 cM with an average distance of 3.1 cM. Novel regions were covered by the newly mapped loci for a total of 159 cM. Eight linkage groups were assembled instead of the earlier 10 as two small groups (G1a and G8b), previously independent, were joined to their respective major groups (G1b and G8a). Several gaps were also reduced resulting in an improved saturation of the map. Twelve gaps >or=10 cm are still present. A comparative analysis against the Prunus reference map (71 anchor loci) pointed out an almost complete synteny and colinearity. Six loci were not syntenic and only two were not colinear. Genetic distances were significantly longer in our map than in the reference one.

Chia seed (Salvia hispanica L.) as an omega-3 fatty acid source for broilers: influence on fatty acid composition, cholesterol and fat content of white and dark meats, growth performance, and sensory characteristics

Five thousand four hundred, 1-d-old, male, Ross 308, broiler chicks were fed for 49 d to compare diets containing 10 and 20% chia (Salvia hispanica L.) seed to a control diet. Cholesterol content, total fat content, and fatty acid composition of white and dark meats were determined at the end of the trial. A taste panel assessed meat flavor and preference. Cholesterol content was not significantly different among treatments; however, the 10% chia diet produced a lower fat content in the dark meat than did the control diet. Palmitic fatty acid content was less in both meat types when chia was fed, with differences being significant (P < 0.05), except for the white meat and the 20% chia diet. alpha-Linolenic fatty acid was significantly higher (P < 0.05) in the white and dark meats with the chia diets. Chia significantly lowered the saturated fatty acid content as well as the saturated:polyunsaturated fatty acid and omega-6:omega-3 ratios of the white and dark meats compared to the control diet. No significant differences in flavor or preference ratings were detected among diets. Body weight and feed conversion were significantly lower with the chia diets than with the control, with weight reductions up to 6.2% recorded with the 20% chia diet.

The maize WD-repeat gene ZmRbAp1 encodes a member of the MSI/RbAp sub-family and is differentially expressed during endosperm development

Members of the MSI/RbAp sub-family of WD-repeat proteins are widespread in eukaryotic organisms and form part of multiprotein complexes that are involved in various biological pathways, including chromatin assembly, regulation of gene transcription, and cell division. In this study we report the isolation and characterization of a cDNA sequence from Zea mays, which encodes an RbAp-like protein (ZmRbAp1) that binds acetylated histones H3 and H4 and suppresses mutations that have a negative effect on the Ras/cAMP pathway in yeast. The ZmRbAp genes form a gene family and are expressed in different tissues of Z. mays L. plants. Determination of its expression pattern during maize seed development revealed that ZmRbAp transcripts are abundant during the initial stages of endosperm formation. In addition, the transcripts are specifically localized in shoot apical meristem and leaf primordia of the embryo. A possible role for the ZmRbAp genes in early endosperm differentiation and plant development is discussed.

Specific combinations of zein genes and genetic backgrounds influence the transcription of the heavy-chain zein genes in maize opaque-2 endosperms

The transcript levels of heavy-chain zein genes (zH1 and zH2) and the occurrence of the zH polypeptides in different opaque-2 (o2) lines were investigated by RNA-blot analyses and by sodium dodecylsulfate-polyacrylamide gel electrophoresis or two-dimensional gel electrophoresis protein fractionations. Four mutant alleles o2R, o2T, o2It, and o2-676 introgressed into different genetic backgrounds (GBs) were considered. The mono-dimensional gel electrophoresis zein pattern can be either conserved or different among the various GBs carrying the same o2 allele. Likewise, in the identical GB carrying different o2 alleles, the zein pattern can be either conserved or differentially affected by the different mutant allele. Zein protein analysis of reciprocal crosses between lines with different o2 alleles or the same o2 showed in some case a more than additive zH pattern in respect to the o2 parent lines. Electrophoretic mobility shift assay approaches, with O2-binding oligonucleotide and endosperm extracts from the above o2 lines, failed to reveal o2-specific retarded band in any of the o2 extracts. The results suggest that the promoter of some zH1 and zH2 contains motif(s) that can respond to factors other than O2.

Variety identification in maize lines via capillary electrophoresis of zeins in isoelectric acidic buffers

Zeins (the prolamins or seed storage proteins in maize) have been used to characterize and identify different genotypes. Zeins were fractionated by capillary zone electrophoresis in acidic, amphoteric buffers, which represent a medium of moderate conductivity and are thus compatible with higher voltage gradients. The running buffer consisted of 40 mM isoelectric aspartic acid, in presence of 6 M urea and 0.5% hydroxyethyl cellulose (apparent pH: 3.8; pI in the absence of urea: 2.77). Thirty-one different zein peaks were mapped out of a total of 21 different maize genotypes. Each of them typically exhibited seven to twelve peaks, with some genotypes showing up to 20 zein bands. Due to slightly changing elution times, caused by a lack of reproducibility of the electroendoosmotic flow in uncoated silica surfaces, correct peak assignment and alignment among different runs was obtained by multivariate statistical analysis. The present method compares well, both in resolution and total number of peaks, with current protocols adopted for screening of maize inbreds, which consist of isoelectric focusing in agarose gels.

[Early gastric cancer: our experience]

The early gastric cancer (EGC) is a very interesting pathology as it represents the first phase of gastric cancer, curable in most cases. The aim of the present study is to evaluate the outcome of surgical treatment of EGC in 19 consecutive patients. The studied patients were followed up for 5 years, during which they underwent a gastroscopy, a hepatic echography and a TC at one year intervals in case of echographic suspicion. Ten patients with limited involvement of the antrum underwent a gastric resection with Billroth II's reconstruction; five patients with circumscribed involvement of the gastric body underwent a subtotal resection; four patients (one with a multifocal involvement of the gastric body and three with multifocal involvement of the fundus) underwent a total gastrectomy with Roux's reconstruction. All patients underwent a limited lymphadenectomy of the perigastric lymph nodes. By evaluating and comparing the results of the present study with previous data on EGC, we propose gastric resection, subtotal gastrectomy and total gastrectomy, according to the location of neoplasm, with limited lymphadenectomy of perigastric lymph nodes.

[Phyllodes tumor of the breast: diagnostic and therapeutic problems]

Phyllodes tumour (PT) is a rare breast tumor with mixed connective and epithelial components, which usually relapses topically after excision. Five patients with PT took part in the study (4 were positive for benign PT and one was positive for malignant PT at extemporary histological examination). The patients (3) with 3 cm or minus benign lesion had mass excision with a large resection of the surrounding mammary tissue. In the remaining patient with benign neoplasm (8 cm lesion) simple mastectomy was carried out. Finally the patient with malignant PT (5 cm lesion) underwent a simple mastectomy without following chemotherapy or radiotherapy. Follow-up (at 6 and 12 months) consisted of mammography and clinical examination. One out of the 3 patients treated with large resection had a local relapse which was then treated surgically. There was no evidence of relapse at 12 months in the remaining patients with benign tumor. The patient with malignant PT returned to our attention with multiple bone metastases in the thoracic lumbar tract two years later. She received multiple courses of combined radiotherapy and chemotherapy. Local relapses do not appear to affect survival: as a consequence, wide excision should be the primary treatment of benign phyllodes tumors. Total mastectomy has been indicated for malignant phyllodes tumors and for very large tumors.

[Technic of overlapping sphincter anal repair in the treatment of traumatic anal incontinence]

Faecal incontinence is an important disabling symptom in the affected patients. Classically, we divide faecal incontinence in two main types: neurogenic faecal incontinence and traumatic anal incontinence. Traumatic anal incontinence is due to causes damaging sphincteric mechanism directly. The aim of the present study was to evaluate the outcome of overlapping sphincter anal repair procedure in the management of traumatic anal incontinence. To this end we studied 27 patients with traumatic anal incontinence who underwent an overlapping sphincter anal repair procedure according to the method described by Parks and McPartlin in 1971. Mean follow up was up three years and was based mainly both on clinical evaluation with anorectal exploration and manometric values carried out on a 6 monthly basis. When the outcome was evaluated in terms of faecal continence our date were similar to those reported by Parks and Fang. In the subjects studied we haven't reported any major complications apart from one case of abscess, one case of wound's infection and one case of stenosis which were efficaciously treated. Our findings supported the view that overlapping sphincter anal repair procedure is the surgical approach of choice in the patients with traumatic anal incontinence.

[Postanal repair in the treatment of idiopathic neurogenic fecal incontinence]

Faecal incontinence is an important disabling symptom in the affected patients. Classically, we divide faecal incontinence in two main types: traumatic faecal incontinence and neurogenic faecal incontinence. Neurogenic faecal incontinence is characterized by a diffuse weakness of anal sphincter and of the elevator muscles. The aim of the present study was to evaluate the outcome of postanal repair procedure in the management of neurogenic faecal incontinence. To this end we studied 20 patients with neurogenic faecal incontinence who underwent a postanal repair procedure according to the method described by Parks. Mean follow up was up two years and was based mainly both on clinical evaluation and manometric values carried out on a 6 monthly basis. When the outcome was evaluated in terms of faecal incontinence our date were similar to those reported by Parks and Keighley. In the subjects studied we haven't reported any major complications apart from two cases of wound's infection which were efficaciously treated. Our findings supported the view that postanal repair procedure is the surgical approach of choice in the patients with idiopathic neurogenic faecal incontinence.

[Treatment of primary gastric lymphoma in IE/IIE stages]

The primitive gastric lymphoma constitutes 2-5% of malignant gastric neoplasms. The present treatment of such a pathology is not defined, since it seems that this disease deserves a multidisciplinary approach: surgical, chemotherapical, radiotherapical. The authors by means of this study, intend to estimate the results of the therapeutic treatment employed in 18 patients suffering from primitive gastric lymphoma in the stage IE and IIE. From the results obtained by our study, it emerges that in the lymphomata located in the cavity at the stage IE, there takes place the almost total superimposition of the results, in terms of survival to 5 years, in the patients treated surgically and in those treated by chemotherapy. Therefore, in such cases the chemotherapic treatment can be proposed because it is bloodless, the patient appreciates it more and it seems to be accompanied by a very small number of complications. In the patients with lymphomat located in the antrum at the stage IIE, we have obtained good results in terms of survival joining radiotherapy and chemotherapy to surgery, as reported by Moore. Even taking into account the very small number of cases we have considered, we think the primitive gastric lymphoma at the stage IE must be treated by means of chemotherapy, while that one at the stage IIE requires and integrated treatment.