International Journal of Cancer Therapy and Oncology
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Radiotherapy for large cutaneous angiosarcoma of face with RapidArc (VMAT)
Get PDFAngiosarcoma is a rare malignancy of vascular origin. It can affect any part of the body, head and neck region being probably the most common site of diagnosis. We present here a case of Angiosarcoma of face in a 67-year-old elderly gentleman who was treated with RapidArc – volumetric modulated arc therapy (VMAT) for recurrence after surgery, radiotherapy and chemotherapy. As an alternative to Electron Beam Therapy, RapidArc with skin bolus can be considered for large complex shaped targets with irregular surface and tissue inhomogeneity. RapidArc plan can achieve adequate target coverage with acceptable dose homogeneity and conformity
CBCT-based dosimetric verification and alternate planning techniques to reduce the normal tissue dose in SBRT of lung patients
Get PDFPurpose: Confirmation of treatment delivery accuracy in stereotactic body radiotherapy (SBRT) of lung tumors suggests the possibility of treatment margin, or aperture reduction. In this investigation, the dose delivery to lung tumors using SBRT techniques was verified, and the feasibility of normal tissue sparing via aperture reduction or altered prescription isodose line was assessed. Methods: Planned and delivered doses to the gross tumor volume (GTV) and planning target volume (PTV) were compared for 10 patients using planning CT and conebeam CT image. Potential for reduction in normal tissue dose were assessed using 2 alternate treatment plans – reduced PTVs and alternate prescription techniques. Plans were assessed using conformity index, homogeneity index and the ratio of 50% / 100% isodose volumes (R50%). Results: The planned and delivered mean doses were consistent to within 4%. However, the mean dose delivered to the GTV exceeded the prescription dose (Rx) by 19% and is consistent with our planning technique of prescribing to the 80% isodose line. When reducing treatment margins and retaining a constant dose-volume constraint, block margins had to be increased which produced a constant effective field aperture outside of the GTV. Prescription to a lower isodose line using stereotactic-like planning techniques yielded the only method by which the volume of the prescription isodose could be affected, although this yielded increases in normal tissue dose due to the increased monitor units required. Conversely, conventional prescription techniques using wider field apertures were effective in reducing absolute values of normal tissue dose. Although dose conformity was similar across different prescription isodose lines, homogeneity index and R50% values were significantly different in the 60%-70% prescription isodose line plans than the 80%, 90% prescription plans.Conclusion: Traditional margin reduction techniques did not affect a reduction in the volume of normal tissue irradiated to the prescribed dose. Prescribing to low isodose lines yields reduced volumes of the prescribed dose, but at the expense of normal tissue dose.
Electrochemical sensors in breast cancer diagnostics and follow-up
No full textPurpose: The detection of tumor biomarkers can have a major contribution to the management of breast cancer. So far the only serum biomarker in current use in breast cancer is the cancer antigen 15-3 (CA15-3). This biomarker is used in advanced breast cancer to monitor patients and to help to identify treatment failure. The human epidermal growth factor receptor 2 (HER 2) is another biomarker whose characterization is usually made in tissue samples from primary tumour or metastasis and has been used as a prognostic factor but mainly as a target in immunotherapy treatment. Some previous studies suggest that the detection of the extracellular domain of HER2 (HER2-ECD) in blood can be a prognostic factor, with even better results than its detection in tissue. Recent techniques for circulating protein biomarker detection use immunoassays, but some are, for example, not sufficiently sensitive for the detection of low biomarker concentrations. To overcome some of these problems, electrochemical (bio)sensors, and especially the ones using voltammetric detection, can be adequate alternatives because of their high selectivity and sensitivity which allows early detection of many diseases. Furthermore, electrochemical (bio)sensors are excellent to be included into point-of-care devices due to their fast response, simplicity, low cost, easy miniaturization and integration into automatic systems. Another advantage is the possibility of combining individual sensors into multiplexed detection systems. Like this they can provide fast recording of biomarker profiles of tumours which can play an important role in early detection and personalized medicine.Methods: Both individual as well as multiplexed electrochemical immunosensors were developed for the detection of CA15-3 and HER2-ECD. For this purpose a sandwich immunoassay was employed and the analytical signal was based on the voltammetric detection of enzymatically deposited silver. Screen-printed carbon electrodes (SPCEs) were used as the transducers. These SPCEs (working volume: ~40 μL) are widely employed in the construction of electrochemical (bio)sensors because of several reasons: simplicity and low cost, versatility of design, small dimensions and possibility of incorporation in portable systems, as well as adequate electroanalytical characteristics. These SPCEs were modified with gold nanoparticles (nAu) through the electrochemical deposition of ionic gold from a solution. The developed sensors were applied to the analysis of the selected biomarkers in spiked human serum samples.Besides these immunosensors, a molecularly imprinted polymer (MIP) sensor was developed for the analysis of HER2-ECD. In this case a gold electrode was used as the transducer. The MIP was formed by surface imprinting and electrochemical impedance spectroscopy and voltammetry were used for detection purposes.Results: For the immunoassays the following parameters were optimized: capture and detection antibody concentration, surface blocking, reaction mixtures and incubation times. The best limits of detection obtained were below the established cut-off values (25 U/mL and 15 ng/mL for CA15-3 and HER2-ECD, respectively). For the MIP sensor the most adequate polymer was chosen and the electropolymerization, template removal, and incubation conditions were optimized. The lowest HER2-ECD concentration that was analyzed was 50 µg/mL.Conclusion: The obtained results indicate that the developed sensors could be promising tools in breast cancer diagnostics and follow-up. However, further studies should be conducted using patients' samples and the results of these assays should be validated with the established analysis procedures for these cancer biomarkers.-----------------------------------------Cite this article as: Marques R, Pacheco J, Rama EC, Viswanathan S, Nouws H, Delerue-Matos C. Electrochemical sensors in breast cancer diagnostics and follow-up. Int J Cancer Ther Oncol 2015; 3(4):34012.[This abstract was presented at the BIT’s 8th Annual World Cancer Congress, which was held from May 15-17, 2015 in Beijing, China.
Comparison between measured tissue phantom ratio values and calculated from percent depth doses with and without peak scatter correction factor in a 6 MV beam
Get PDFThe purpose of this study is to examine the accuracy of calculated tissue phantom ratio (TPR) data with measured TPR values of a 6MV photon beam. TPR was calculated from the measured percent depth dose (PDD) values using 2 methods – with and without correcting for the differences in peak scatter fraction (PSF). Mean error less than 1% was observed between the measured and calculated TPR values with the PSF correction, for all clinically relevant field sizes and depths. When not accounting for the PSF correction, mean difference between the measured and calculated TPR values was larger than 1% for square field sizes ranging from 3 cm to 10 cm
Optimal usage of cone beam computed tomography system with different field of views in image guided radiotherapy (IGRT)
Get PDFPurpose: To find methods for optimal usage of XVI (X-ray volume imaging) system in Elekta synergy linear accelerator with different field of views for same lesion in order to minimize patient dose due to imaging.Methods: 20 scans of 2 individual patients with ca sigmoid colon and ca lung were used in this study. Kilo voltage collimators with medium field of view were used as per the preset information. Images were reconstructed for another collimator with small field of view. The set up errors were evaluated with XVI software. Shift results of both methods were compared. Results: Variation in treatment set up errors with M20 and S20 collimators were ≤ 0.2 mm in translational and 0.30 in rotational shifts. Results showed almost equal translational and rotational shifts in both medium and small field of views with different collimators in all the scans. Visualization of target and surrounding structures were good enough and sufficient for XVI auto matching.Conclusion: Imaging with small field of view results less patient dose compared with medium or large field of views. It is Suggestible to use collimators with small field of view wherever possible. In this study, collimators with small field of view were sufficient for both patients though the preset information indicated medium field of view. But, it always depends on the area required for matching purpose. So, individual selection is important than preset information in the XVI system
Evaluation of surface dose outside the treatment area for five breast cancer irradiation modalities using thermo-luminescent dosimeters
Get PDFPurpose: To measure and compare the surface dose outside the treatment area at six different points of interest (POIs) for five different breast cancer radiation treatment modalities by using thermo-luminescent dosimeters (TLDs). This experiment will evaluate the magnitude of the dose due to scatter and leakage radiation at different areas outside the target on a patient that could potentially lead, in the long term, to radiation induced secondary malignancies.Methods: TLD-100 were calibrated according to the University of Wisconsin Radiation Calibration Laboratory protocol and then used for dose measurements at selected POIs namely sternum, lower abdomen, contralateral breast, thyroid, shoulder, and eye. Twenty five breast cancer patients and the following modalities were included in this study: Strut-adjusted volume implant (SAVI), mammosite multi-lumen (ML), Accuboost, electron boost and photon boost. The surface doses in all patients were measured in a single fraction. The delivered target doses were normalized to 200 cGy. Finally, breast quadrant analysis was performed.Results: The maximum average dose for each POI was as follows: Sternum 6.51 cGy (SD 2.93), lower abdomen 4.50 cGy (SD 2.63), contralateral breast 8.52 cGy (SD 3.86), thyroid 5.50 cGy (SD 2.75), shoulder 5.58 cGy (SD 2.77), and eye 2.65 cGy (SD 0.68). The highest POI dose of 15.84 cGy was found in contralateral breast.Conclusion: The measured surface dose at each POI varies with the modality of treatment. The surface doses show a strong correlation to the tumor bed location in the breast quadrant. The SAVI, electron boost, and photon boost modalities had delivered smaller surface dose at POIs than the Accuboost and Mammosite ML modalities. While the measured doses fall within the low range, its significance in producing second malignancies would require a large cohort of patients and a longer follow up
Impact of patient positioning on radiotherapy dose distribution: An assessment in parotid tumor
Get PDFPurpose: We intended to study the impact of patient positioning on the dose distribution within target volume and organs at risk in patients with parotid malignancies treated with 3D conformal radiotherapy (3D-CRT) with photon wedge pair (WP) or intensity modulated radiotherapy (IMRT).Methods: Three patients with a non-Hodgkin’s lymphoma of the right parotid gland were consecutively immobilized using thermoplastic cast in 2 positions: supine with head in neutral position (HN) and with head turned 90° to the left side (HT). Images for treatment planning purpose were acquired in both positions. For both positions, photon WP plans and 5 field IMRT plans were generated, after contouring clinical target volume (CTV), planning target volume (PTV= CTV + 5 mm margin) and organs at risk (OAR). All plans were evaluated for target coverage and dose to OARs.Results: Both CTV and PTV were apparently larger in HN compared with HT (31.76±8.89 cc, 30.31±7.83 cc and 62.49±19.01 cc, 58.89±15.33 cc) respectively. The CI value for PTV was slightly better for HT compared to HN position in both the WP and IMRT plans. The homogeneity was comparable in both the head positions in case of WP plan. The mean HI of PTV was increased in case of IMRT plan at HT versus HN position (1.108 vs. 1.097). A change in head position from HN to HT with wedge pair plan resulted in a reduction of brainstem Dmax and Dmean. Lesser dose was observed in HN position for contralateral parotid. A difference of 0.9 Gy in the average Dmax to spinal cord was seen. The values of Dmean to mandible, oral cavity, ipsilateral and contralateral cochlea were higher in the HT position. A change in head position from HN to HT with IMRT plan resulted in a dose reduction in average Dmax to brainstem. The spinal cord Dmax increased at the HT position by 1.2 Gy. The dose to contralateral parotid and cochlea was comparable in both the positions. However, the Dmean to oral cavity was reduced at HT position. Whereas for IMRT versus wedge pair plan at head neutral position average Dmean to the contralateral parotid was reduced with the IMRT plan. A considerable reduction in Dmax to spinal cord and Dmean to ipsilateral cochlea was observed. A slight increase in average Dmax to brainstem and was observed with the IMRT plan. The doses to the remaining OARs were lesser in case of IMRT plan. For IMRT versus wedge pair plan at head tilt position slight increase in average Dmax to brainstem was observed in case of IMRT plan. A considerable reduction in Dmax to spinal cord and Dmean to ipsilateral cochlea was observed. The doses to the remaining OARs were reduced with IMRT plan.Conclusion: Change in head position from neutral to 90° contralateral tilt for wedge pair plan in parotid tumor may considerably reduce dose to the brainstem and spinal cord with a modest increase in dose to mandible, oral cavity, contralateral parotid, and bilateral cochlea. The alteration in head position has minimal impact on IMRT planning
Pancreatic neuroendocrine tumor in an individual with Von Hippel Lindau syndrome. A case report and review literature
Get PDFVon Hippel Lindau (VHL) disease is a heritable cancer syndrome characterized by VHL gene mutation in 3p chromosome. Mutations occur at the exons. Rarely mutations at introns have been reported. It leads to accumulation of Hypoxic ischemic factor α (HIF α) which in turn leads to uncontrolled cellular proliferation. Few reports of pancreatic neuroendocrine tumors (PNETs) are there in the literature. Most of them are associated with a mutation in the exon of VHL gene. Association with intron mutation is not there. Here we are reporting a case of PNET in a patient who has a simultaneous mutation both at the exon and the intron
Development and biodistrubition modeling of 99mTc-DTPA
Get PDFPurpose: In this study, the team modeled the biodistribution and the efficiency of two 99m-technetium diethylene triamine penta acetate (99mTc-DTPA) based radiopharmaceuticals.Methods: The first radiopharmaceutical (DTPA-CNESTEN) is developed at the laboratories of the radiopharmaceutical production unit of the National Center for Nuclear Energy, Sciences and Technologies (CNESTEN-Morocco), and the second one is the commercial DTPA (DTPA-ref). Freeze-dried kits were successfully radiolabeled (radiochemical purity >95%) with the 99m Tc. Then drugs were injected to male BALB/c mice. In each 2 min, 5 min, 15 min, 1 h and 2 h time points after injections we evaluate tissue’s distributions characteristics. At the end, an automatic modeling of the data were recorded from thyroid, blood and urinary excretion kinetics and biodistribution in mice using both DTPA kits. The study aimed to extract the parameters of the function used to fit the recorded data. Results and Conclusion: the team concluded that the biodistribution of 99mTc-DTPA can be modeled using a combination of two exponential parts. Moreover, the resultant plots showed that there is strong correlation between the formula found in literature and the one derived on the basis of the fit of data sets in this study. In addition, it was found that the biodistribution behaviors of the developed kit and the commercial one were very close. The obtained results suggest that the developed DTPA has practically the same kinetics as the commercial one
In vitro animal cancer model for assessment of sulfated polysaccharides extract of Ulva lactuca as colon cancer therapeutic and chemopreventive agents
No full text******This paper has been withdrawn by the corresponding author on August 09, 2015*****