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ABSTRACT: Background and purposes: To compare the dosimetry for the left-sided breast cancer treatment using five different radiotherapy techniques.Materials and methods: Twenty patients with left sided breast cancer were treated with conservative surgery followed by radiotherapy. They were planned using five different radiotherapy techniques, including: 1) conventional tangential wedge-based fields (TW); 2) field-in-field (FIF) technique; 3) tangential inverse planning intensity-modulated radiation therapy (T-IMRT); 4) multi-field IMRT (M-IMRT); and 5) volumetric modulated arc therapy (VMAT). The CTV, PTV and OARs including the heart, the regions of coronary artery (CA), the contralateral breast, the left and right lung were delineated. The PTV dose was prescribed 50Gy and V47.5>=95%. Same dose constraint was used for all five plans. The planned volumetric dose of PTV and PRV-OARs were compared and analyzed. RESULTS: Except VMAT (Average V47.5 was 94.72%+/-1.2%), all the other four plans were able to meet the V95% (V47.5) requirement. T-IMRT plan improved the PTV dose homogeneity index (HI) by 0.02 and 0.03 when compared to TW plan and VMAT plan, and decreased the V5, V10 and V20 of all PRV-OARs. However, the high dose volume (>= 30Gy) of the PRV-OARs in T-IMRT plan had no statistically significant difference compared with the other two inverse plans. In all five plans, the dose volume of coronary artery area showed a strong correlation to the dose volume of the heart (the correlation coefficients were 0.993, 0.996, 1.000, 0.995 and 0.986 respectively). CONCLUSION: Compared to other techniques, the T-IMRT technology reduced radiation dose exposure to normal tissues and maintained reasonable target homogeneity, VMAT is not recommended for left-sided breast cancer treatment. In five techniques, the dose-volume histogram (DVH) of the heart can be used to predict the dose-volume histogram (DVH) of the coronary artery.
Radiation Oncology 04/2013; 8(1):89. · 2.32 Impact Factor
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ABSTRACT: The present study aimed to investigate the effects of ursolic acid on the chloride channels and cell volume in nasopharyngeal carcinoma cells (CNE-2Z). The whole-cell patch clamp technique was used to detect the current, and cell imaging technique was applied to measure cell volume. The properties of the currents induced by ursolic acid were investigated by changing the extracellular osmotic pressure, replacing the extracellular anions and applying chloride channel blockers. The results showed that, under isotonic conditions, the background current was weak and stable. When perfusing the cells with ursolic acid (100 nmol/L), a large current (-59.86 pA/pF ± 4.86 pA/pF at -80 mV, 78.92 pA/pF ± 6.39 pA/pF at +80 mV) was induced. The chloride current showed outward rectification and negligible time- and voltage-dependent inactivation. The reversal potential (-4.83 mV ± 0.30 mV) of the current was close to the calculated equilibrium potential for Cl(-) (-0.9 mV). The permeabilities of the channel to different anions were ranked in order as follows: Cl(-) = I(-) > Br(-) > gluconate. Hypertonic solutions inhibited the current induced by ursolic acid. The chloride channel blockers, tamoxifen (20 μmol/L) and 5-nitro-2-(3-phenylpro-pylamino) benzoic acid (NPPB, 100 μmol/L), suppressed the current. Furthermore, ursolic acid decreased the cell volume by (11.78 ± 1.20)% in 1 h, and the effect was inhibited by NPPB. These results suggest that ursolic acid can activate chloride channels, resulting in outflow of Cl(-) and decrease of cell volume in nasopharyngeal carcinoma cells.
Sheng li xue bao: [Acta physiologica Sinica] 12/2012; 64(6):673-80.
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ABSTRACT: The present study aimed to clarify the effect of berberine on the chloride channels in human colorectal carcinoma cells (SW480). The whole-cell patch clamp technique was used to detect the Cl(-) current activated by berberine. The physiological and pharmacological characteristics of the current were clarified by changing the osmotic pressure of extracellular perfusate and applying chloride channel blockers. The results showed that, under isotonic conditions, the background current of SW480 cells was weak and stable. A large current was induced by perfusing the cells with the isotonic solution containing berberine (10 nmol/L), current density being (85.8 ± 4.6) pA/pF at +80 mV, (-71.9 ± 3.5) pA/pF at -80 mV, with a latency of (115.6 ± 21.7) s. The chloride current showed weak outward rectification and negligible time- and voltage-dependent inactivation. The reversal potential (-5.5 mV ± 1.2 mV) of the current was close to the calculated equilibrium potential for Cl(-) (ECl = -0.9 mV). Experiments under different osmotic pressures showed that the properties of hypotonicity-activated current recorded in SW480 cells were similar to those of the current induced by berberine, and hypertonic solutions suppressed the berberine-induced current by (98.6 ± 2.3)%. On the other hand, berberine-induced Cl(-) current was significantly inhibited by the chloride channel blockers NPPB (100 µmol/L) and tamoxifen (20 μmol/L), with the inhibition ratios of (83.1 ± 3.6)% and (95.6 ± 1.2)% respectively. These results suggest that berberine can activate the chloride channels that are sensitive to NPPB and tamoxifen, as well as the changes of cell volume in human colorectal carcinoma cells.
Sheng li xue bao: [Acta physiologica Sinica] 12/2011; 63(6):517-24.
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ABSTRACT: To investigate the role of chloride channels in the apoptosis of poorly differentiated nasopharyngeal carcinoma CNE-2Z cells induced by gambogic acid (GA).
MTT assay was applied to detect the proliferation of CNE-2Z cells after GA treatment, and the cell apoptosis was detected by Hoechst 33342 staining. Whole-cell patch clamp technique was employed to record GA-activated Cl(-) currents in the cells.
GA inhibited the cell proliferation in a time- and concentration-dependent manner with an IC(50) of 3.1 µmol/L for a 48-h treatment. The apoptosis-inducing effect of 8 µmol/L GA was attenuated by the chloride channel blocker NPPB (100 µmol/L) and tamoxifen (20 µmol/L). GA induced an outward-rectified Cl(-) current in the cells, which was significantly inhibited by NPPB.
GA suppresses cell proliferation and induces apoptosis by activating Cl(-) channels in CNE-2Z cells, suggesting the important role of Cl(-) channels in GA-induced apoptosis.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 08/2011; 31(8):1304-8.
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ABSTRACT: A growing number of studies worldwide have advocated the replacement of whole-breast irradiation with accelerated partial breast irradiation using three-dimensional conformal external-beam radiation (APBI-3DCRT) for early-stage breast cancer. But APBI can be only used in selected population of patients with early-staged breast cancer. It is not replacing the whole breast radiotherapy. This study aimed to examine the feasibility and acute normal tissue toxicity of the APBI-3DCRT technique in Chinese female patients who generally have smaller breasts compared to their Western counterparts.
From May 2006 to December 2009, a total of 48 Chinese female patients (with early-stage breast cancer who met the inclusion criteria) received APBI-3DCRT after breast-conserving surgery at Sun Yat-sen University Cancer Center. The total dosage from APBI-3DCRT was 34 Gy, delivered in 3.4 Gy per fractions, twice per day at intervals of at least six hours. The radiation dose, volume of the target area and volume of irradiated normal tissues were calculated. Acute toxicity was evaluated according to the Common Toxicity Criteria (CTC) 3.0.
Among the 48 patients, the planning target volume for evaluation (PTVE) was (90.42 ± 9.26) cm³, the ipsilateral breast volume (IBV) was (421.74 ± 28.53) cm³, and the ratio between the two was (20.74 ± 5.86)%. Evaluation of the dosimetric characteristics of the PTVE revealed excellent dosimetric results in 14 patients and acceptable results in 34 patients. The dose delivered to the PTVE ranged from 93% to 110% of the prescribed dose. The average ratio of the volume of PTVE receiving 95% of the prescription dose (V95) was (99.26 ± 0.37)%. The habituation index (HI) and the conformity index (CI) were 1.08 ± 0.01 and 0.72 ± 0.02, respectively, suggesting good homogeneity and conformity of the dose delivered to the target field. The radiation dose to normal tissues and organs was within the dose limitation. Subjects experienced mild acute toxicity. The main manifestations were breast edema in 22 patients, breast pain in 7, skin erythema in 25, general malaise in 22 and cytopenia in 8. No acute radiological cardiac or pulmonary injury was found.
The results of our short-term follow-up showed that it is feasible to perform APBI-3DCRT for early-stage breast cancer after breast-conserving surgery in Chinese female patients with smaller breasts. However, further studies are required to elucidate its efficacy and long-term side effects.
Chinese medical journal 05/2011; 124(9):1305-9. · 0.86 Impact Factor
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ABSTRACT: To investigate the role of ClC-3 chloride channels in regulatory volume decrease (RVD) of nasopharyngeal carcinoma (NPC) CNE-2Z cells.?
ClC-3 siRNA was transfected into CNE-2Z cells in the presence of the transfection reagent HiPerFect Reagent(TM). The transfection efficiency of ClC-3 siRNA was detected by flow cytometry. The expression of ClC-3 protein was detected by Western blotting, and the changes of cell volume in 160 mOsmol/L hypotonic solution were determined by image analysis.
The transfection efficiency of ClC-3 siRNA was (63.8∓3.8)% (n=3, P<0.01), and compared with the control group, ClC-3 siRNA transfection resulted in a reduction of ClC-3 expression by (60.9∓4.0)% (n=3, P<0.01). The hypotonic challege (160 mOsmol/L) caused cell swelling and induced RVD. In the control group, hypotonic solution bath for 35 min resulted in a RVD of (42.6∓2.8)% (n=20), which was significantly decreased to (10.5∓4.8)% (n=16) in ClC-3 siRNA-transfected cells, demonstrating a reduction of RVD capacity by 75.4% (P<0.01).?
The capacity of RVD is significantly reduced in CNE-2Z cells by ClC-3 chloride channel protein knock-down via ClC-3 siRNA transfection, indicating an important role of ClC-3 chloride channels in the RVD of CNE-2Z cells.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 02/2011; 31(2):216-20.
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ABSTRACT: Responses of human mesenchymal stem cells from bone marrow (hBMSCs) were analyzed under chemical conditions, and then characterization of ion channels was evaluated by whole-cell patch clamp.
To explore the possibility of differentiation of human bone marrow-derived mesenchymal stem cells into neuron-like cells in vitro under different conditions.
The generation of mesenchymal stem cells into neuron-like cells has been studied. However, few of these studies characterized functional properties of the differentiated hBMSCs.
hBMSCs (Passage 2) were expanded and cultured in vitro. After Passage 5 was subcultured, the cells were induced by cytokines and antioxidants. Morphologic observation, immunocytochemistry, Western blot analysis, and patch-clamp techniques were performed to evaluate properties of treated and control groups.
The differentiated neuronal cells from hBMSCs not only expressed neuron phenotype and membrane channel protein including Nav1.6, Kv1.2, Kv1.3, and Cav1.2 but also exhibited functional ion currents. Both hBMSCs and differentiated cells expressed Nav1.6, Kv1.2, Kv1.3, and Cav1.2 and voltage-activated potassium currents, including delayed rectifier, noise-like and transient outward currents. However, expression of channel proteins, such as sodium channel Nav1.6 and potassium channels Kv1.2 and Kv1.3, were upregulated. Consistently, their potassium currents were also enhanced in the differentiated cells.
hBMSCs possess of great potential to differentiate into functional neurons, indicating that hBMSCs may be an ideal cell source in managing a variety of clinical diseases such as spinal cord injury.
Spine 01/2011; 36(13):997-1005. · 2.08 Impact Factor
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ABSTRACT: A new triterpenoid, 4,4,14α-trimethyl-5α-chol-7,9(11)-dien-3-oxo-24-oic acid (1), together with seven known triterpenoids, were isolated from the dried fruiting bodies of Ganoderma lucidum. Their structures were elucidated by extensive spectroscopic analyses. Bioassay results revealed that compounds 1 and methyl ganoderic acid B (5) had nerve growth factor-like neuronal survival-promoting effects, whereas compounds 1, and 4-7 showed brain-derived neurotrophic factor-like neuronal survival-promoting activities.
Natural product research 01/2011; 25(17):1607-13. · 1.01 Impact Factor
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ABSTRACT: The planning dose distribution of intensity-modulated radiation therapy (IMRT) has to be verified before clinical implementation. The commonly used verification method is to measure the beam fluency at 0 degree gantry angle with a 2-dimensional (2D) detector array, but not the composite dose distribution of the real delivery in the planned gantry angles. This study was to investigate the angular dependence of a 2D diode array (2D array) and the feasibility of using it to verify the composite dose distribution of IMRT.
Angular response of the central detector in the 2D array was measured for 6 MV X-ray, 10 cmx10 cm field and 100 cm source axis distance (SAD) in different depths. With the beam incidence angle of 0-60 degrees, at intervals of 10 degrees, and inherent buildup of the 2D array (2 g/cm2), the array was irradiated and the readings of the central diode were compared with the measurement of thimble ionization chamber. Using a combined 30 cmx30 cmx30 cm phantom which consisted of solid water slabs on top and underlying the 2D array, with the diode detectors placed at 8 g/cm2 depth, measurements were taken for beam angles of 0 degrees-180 degrees at intervals of 10 degrees and compared with the calculation of treatment planning system (TPS) that pre-verified with ion chamber measuring.
Differences between the array detector and thimble chamber measurements were greater than 1% and 3.5% when the beam angle was larger than 30 degrees and 60 degrees, respectively. The measurements in the combined phantom were different from the calculation as high as 20% for 90 degrees beam angle, 2% at 90 degrees+/-5 degrees and less than 1% for all the other beam angles.
The 2D diode array is capable of being used in composite dose verification of IMRT when the beam angles of 90 degrees+/-5 degrees and 270 degrees+/-5 degrees are avoided.
Chinese journal of cancer 06/2010; 29(6):617-20.
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ABSTRACT: To ensure the accuracy of dose calculation for radiation treatment plans is an important part of quality assurance (QA) procedures for radiotherapy. This study evaluated the Monitor Units (MU) calculation accuracy of a third-party QA software and a 3-dimensional treatment planning system (3D TPS), to investigate the feasibility and reliability of independent verification for radiation treatment planning.
Test plans in a homogenous phantom were designed with 3-D TPS, according to the International Atomic Energy Agency (IAEA) Technical Report No. 430, including open, blocked, wedge, and multileaf collimator (MLC) fields. Test plans were delivered and measured in the phantom. The delivered doses were input to the QA software and the independent calculated MUs were compared with delivery. All test plans were verified with independent calculation and phantom measurements separately, and the differences of the two kinds of verification were then compared.
The deviation of the independent calculation to the measurements was (0.1 +/- 0.9)%, the biggest difference fell onto the plans that used block and wedge fields (2.0%). The mean MU difference between the TPS and the QA software was (0.6 +/- 1.0)%, ranging from -0.8% to 2.8%. The deviation in dose of the TPS calculation compared to the measurements was (-0.2 +/- 1.7)%, ranging from -3.9% to 2.9%.
MU accuracy of the third-party QA software is clinically acceptable. Similar results were achieved with the independent calculations and the phantom measurements for all test plans. The tested independent calculation software can be used as an efficient tool for TPS plan verification.
Chinese journal of cancer 02/2010; 29(2):217-22.
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ABSTRACT: X-ray stereotactic radiotherapy (SRT) is one of the effective treatments for brain metastases (BM). This study was to evaluate the efficacy of SRT on BM, and investigate prognostic factors.
Between July 1999 and December 2004, a total of 122 intracranial lesions in 78 patients with BM were treated using SRT in our Center. Forty-nine patients had a solitary lesion and 29 had multiple (2-6) lesions. The median SRT dose was 15 Gy (11-24 Gy) in single fraction for 38 lesions, and 24 Gy (11-40 Gy) in 2-6 fractions for 84 lesions. SRT was combined with whole brain radiotherapy (WBRT) of 30-40 Gy for 39 patients. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier method. Univariate and multivariate analyses were performed by the log-rank test and Cox model, respectively.
The median survival time was 12.9 months (1.7-77.4 months). The 1-year intracranial PFS rate was 87.4%. The 1-and 2-year OS rates were 53.9% and 25.8%, respectively. Univariate analysis showed that the 1-year OS rates were higher in the patients with pretreatment KPS of >/= 70, extracranial lesions controlled, or SRT combined with WBRT than in those with KPS of < 70 (60.7% vs. 29.4%, P = 0.002), extracranial lesions uncontrolled (69% vs. 44.9%, P = 0.005), or SRT alone (64.1% vs. 43.4%, P = 0.03). The benefit of treating with WBRT in combination was mainly achieved in the patients with extracranial lesions controlled or with more than one intracranial lesion. Multivariate analysis showed that KPS score and status of extracranial lesions were independent prognostic factors for OS.
SRT is an effective and safe modality for BM. SRT combined with WBRT may prolong the survival time of the patients with extracranial lesions controlled or multiple intracranial lesions. Independent prognostic factors for OS are KPS score and status of extracranial lesions.
Chinese journal of cancer 02/2010; 29(2):202-6.
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ABSTRACT: To construct the eukaryotic expression vectors of human cyclin D1 gene and express them in poorly differentiated nasopharyngeal carcinoma cells (CNE-2Z cells).
The full-length cyclin D1 was cloned from CNE-2Z cells by RT-PCR. The cDNA fragments were inserted into pIRES2-EGFP plasmids and pEGFP-C2 plasmids and confirmed by restriction enzyme digestion, PCR and sequencing. The recombinant vectors were transfected into CNE-2Z cells via Lipofectamine 2000, and the expression of cyclin D1 in the cells was examined by immunofluorescence and Western blotting.
Agarose gel electrophoresis showed a 918 bp band of the RT-PCR products, which matched the expected size. Restriction enzyme digestion, PCR and sequencing demonstrated successful construction of the recombinant vectors. CNE-2Z cells transfected with the recombinant vectors expressed cyclin D1 protein or cyclin D1-GFP protein as were verified by immunofluorescence and Western blotting.
We have cloned cyclin D1 gene and constructed its eukaryotic expression vectors that can be expressed in nasopharyngeal carcinoma cells, which may facilitate the study of the role of cyclin D1 in the development of nasopharyngeal carcinoma.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 02/2010; 30(2):202-5.
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ABSTRACT: The aim of this study was to use four-dimensional CT (4DCT) in the planning of 3D conformational external beam radiation therapy (3DCRT) for patients with early stage breast cancer. A total of nine Chinese women who received breast conservation treatment were included in this study. Target localization and movement (range of motion) during normal respiration were assessed using ultrasound and 4DCT. Plans based on 3DCT and 4DCT scans were developed in accordance to RTOG0319 guidelines and dose delivery comparisons were made between these plans. The mean ranges of motion of the excision cavity volume as determined using 4DCT were 1.03 +/- 0.51, 2.08 +/- 0.92, and 1.27 +/- 0.58 mm in the right-left, anterior-posterior, and superior-interior directions, respectively. There were no significant differences between the mean and maximum PTV-E doses or the volume receiving 95% of the prescribed dose (V95). 4D plan prescribed dose levels were significantly lower (p < 0.05) than 3D plan levels for all of the following: ipsilateral breast V100, ipsilateral lung V30, and contralateral lung V5. Maximum contralateral breast and thyroid doses were also significantly lower with the 4D plan (p < 0.05). This study highlights the usefulness of 4DCT for the planning of 3DCRT in breast cancer patients. Our findings suggest that the use of 4DCT can lead to improvements in target definition and decreases in normal tissues irradiation.
Oncology Research Featuring Preclinical and Clinical Cancer Therapeutics 01/2010; 18(10):503-7. · 1.30 Impact Factor
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ABSTRACT: The purpose of this work was to evaluate the absorbed dose to AL2O3 dosimeter at various depths of water phantom in radiotherapy photon beams by Monte Carlo simulation and evaluate the beam quality dependence.
The simulations were done using EGSnrc. The cylindrical Al2O3 dosimeter (Phi4 mm x 1 mm) was placed at the central axis of the water phantom (Phi16 cm x 16 cm) at depths between 0.5 and 8 cm. The incident beams included monoenergetic photon beams ranging from 1 to 18 MeV, 60Co gamma beams, Varian 6 MV beams using phase space files based on a full simulation of the linac, and Varian beams between 4 and 24 MV using Mohan's spectra. The absorbed dose to the dosimeter and the water at the corresponding position in the absence of the dosimeter, as well as absorbed dose ratio factor fmd, was calculated.
The results show that fmd depends obviously on the photon energy at the shallow depths. However, as the depth increases, the change in fmd becomes small, beyond the buildup region, the maximum discrepancy of fmd to the average value is not more than 1%.
These simulation results confirm the use of Al2O3 dosimeter in radiotherapy photon beams and clearly indicate that more attention should be paid when using such a dosimeter in the buildup region of high-energy radiotherapy photon beams.
Medical Physics 10/2009; 36(10):4421-4. · 2.83 Impact Factor
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ABSTRACT: It has been shown that cell volume regulation mechanisms play important roles in various cell functions. We demonstrated previously that volume-activated chloride channels were involved in cell volume regulation. The present study aimed to clarify the roles of various types of potassium channels in regulatory volume decrease (RVD) induced by hypotonic challenges in human nasopharyngeal carcinoma cells (CNE-2Z cells). The whole-cell patch clamp technique was used to record hypotonic challenge-induced potassium currents. During current recordings, cells were held at 0 mV and stepped to +/-46 and +/-92 mV, repeatedly. The cell volume was computed from cell diameters. The changes of cell volume were monitored and analyzed by the time-lapse imaging technique. The results showed that the exposure to 160 mOsm/L hypotonic solution caused the cells to swell by (144.5+/-4.2)%, activated a potassium current (59.2 pA/pF+/-13.3 pA/pF at 92 mV), and induced RVD. Cell volume was recovered from hypotonic challenge-induced swelling by (48.9+/-4.6)% after 20 min. The potassium current (at 92 mV) and RVD were inhibited by the calcium-dependent potassium channel blocker, clotrimazole (100 mumol/L), by (98.5+/-2.8)% and (89.3+/-4.9)%, respectively. Depletion of extracellular calcium prevented the activation of the hypotonic challenge-induced potassium current and inhibited the process of RVD. The voltage-gated potassium channel blocker, 4-AP (5 mmol/L), partially inhibited the hypotonic challenge-activated potassium currents by (66.6+/-5.3)% (at 92 mV). These results suggest that the Ca(2+)-dependent potassium channel is the main component of volume-activated potassium channels and plays an important role in volume regulation of CNE-2Z cells. The voltage-gated potassium channels may also contribute in part to the formation of the volume-activated potassium current.
Sheng li xue bao: [Acta physiologica Sinica] 10/2009; 61(5):485-92.
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ABSTRACT: Accurate data acquisition is very important to establish a reliable dose calculation model of the treatment planning system for small radiation fields in intensity modulated radiation therapy (IMRT) and stereotactic radiotherapy (SRT). This study was to analyze and compare small-field measurements using different methods and ionization chambers.
Three types of farmer chambers were used, with active volumes of 0.65 cc, and 0.13 cc, 0.01 cc, respectively. The beam data, including the total scatter factor (Scp), collimator scatter factor (Sc), tissue-maximum ratio (TMR), were acquired in a 30 cm x 30 cm x 30 cm3 water phantom under two linear accelerators. Measurements were performed at accelerating potentials of 4, 6, and 8 MV with the beam size ranging from 1 cm x 1 cm to 10 cm x 10 cm. The measurements were analyzed and compared.
For the beam size of >or=3 cm x 3 cm, the differences in Scp and Sc measurements of the 0.65 cc, 0.13 cc and 0.01 cc ion chambers were within 0.8%, while the differences were much greater for the beam size of less than 3 cm x 3 cm (the maximum difference reached 64%). Using 4, 6 and 8 MV X-rays, Sc measured by the 0.13 cc chamber with an elongated source-to-surface distance (SSD) (>150 cm) were 25.4%, 6.9%, 24.6%, and 1.4%, 1.4%, 2.2% greater than those measured by a standard SSD (100 cm) for 1 cm x 1 cm and 2 cm x 2 cm beams respectively; although there was no significant difference in Sc measurements for the beams of >or=2 cm x 2 cm using the elongated SSD of the 0.13 cc and the 0.01 cc ion chambers, Sc measured by the 0.13 cc ion chamber were 0.2%, 8.5%, 3.4% less than those measured by the 0.01 cc ion chamber for the 1 cm x 1 cm beam. For the 1 cm x 1 cm beam, the TMR of the depth deeper than 15 cm measured with the 0.01 cc ion chamber was about 4% different compared with that measured with the 0.13 cc ion chamber; for radiation fields of >or=2 cm x 2 cm, the differences of TMR between the 0.01 cc and 0.13 cc chambers were within 1%. For the radiation fields of >or=3 cm x 3 cm, the measured TMR values had a good consistency with the calculated values obtained from the percentage depth doses (PDDs) at the depth of 0 to 15 cm; but the two values were obviously different at the depths of deeper than 15 cm (>2%).
For the measurement of small fields, the choice of a suitable detector is important due to the lack of lateral electron equilibrium. Misuse of the detector may affect the accuracy of the measurements for small radiation fields. When the lateral electron equilibrium is not established, the size of the detector used to measure the absorbed dose on the central axis should be considerably smaller than the field size.
Ai zheng = Aizheng = Chinese journal of cancer 04/2009; 28(3):328-32.
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ABSTRACT: To observe the effects of astragalus membranacaus injection on the activity of the intestinal mucosal mast cells (IMMC) and inflammatory response after hemorrahagic shock-reperfusion in rats.
Thirty-two Wistar rats were randomly divided into four groups: normal group, model group, low dosage group, (treated with astragalus membranacaus 10 g kg(-1)) and high dosage group (treated with astragalus membranacaus 20 g kg(-1)). Models of hemorrhage shock for 60 minutes and reperfusion for 90 minutes were created. The animals were administrated 3 mL therapeutic solution before reperfusion. At the end of study, intestinal pathology, ultrastructure of IMMC, and expression of tryptase were observed. The levels of MDA, TNF-a, histamine, and SOD activity of intestinal were detected, and the number of IMMC was counted.
The degranulation of IMMC was seen in model group and was attenuated by astragalus membranacaus treatment. Chiu's score of model group was higher than that of the other groups. Astragalus membranacaus could attenuate the up-regulation of the Chiu' s score, the levels of MDA and TNF-alpha, expression of tryptase, and the down-regulation of SOD activity and histamine concentration. The Chiu's score and MDA content were negatively, while SOD activity was positively correlated to the histamine concentration respectively in the four groups.
Astragalus membranacaus can reduce small intestine mucosal damage by inhibiting the activity of IMMC after hemorrhage shock reperfusion.
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 08/2007; 32(14):1436-40.
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ABSTRACT: To investigate cardiac function impairment and myocardial injury in rats with intestinal ischemia-reperfusion and the protective effect of cromolyn sodium.
Thirty-two SD rats were randomized into 4 groups (n=8), namely the sham operation group, model group, 50 mg/kg cromolyn sodium group, and 25 mg/kg cromolyn sodium group. Intestinal damage was induced by clamping the superior mesenteric artery for 45 min followed by reperfusion for 60 min. Cromolyn Sodium was administrated intaperitoneally 15 min before reperfusion. The heart rate (HR), left ventricle pressure (LVSP), and the maximal/minimum rate of LVSP (+dp/dt(max), -dp/dt(max)) were sacrificed immediately before ischemia (baseline, T(0)), at 15 min (T(1)), 30 min (T(2)), 45 min (T(3)) of ischemia, and at 3 min (T(4)), 5 min (T(5)), 10 min (T(6)), 15 min (T(7)), 45 min (T(8)), 60 min (T(9)) of reperfusion. At the end of the experiment, the rats were executed and the hearts were immediately removed for observation of the pathological changes and determination of MDA contents and SOD activity.
Compared with the baseline T(0), the HR, +dp/dt(max), -dp/dt(max) and the LVSP were decreased significantly at T(8) and T(9) in the model group and the two cromolyn sodium groups (P<0.05). Compared with the sham operation group, these indices were also significantly decreased at T(8) and T(9) in the model group and the two cromolyn sodium groups, but the model group had significantly lower levels for these indices at T(8) and T(9) than the two cromolyn sodium groups (P<0.05). The score of myocardial injury in the model group and the two cromolyn sodium groups were significantly higher than that of group A, and 50 mg/kg cromolyn sodium group had lower score than the model group (P<0.05). The rats in the model group had significantly higher MDA levels than those in the sham operation group and the 50 mg/kg cromolyn sodium group. SOD activities in the model group and 25 mg/kg cromolyn sodium group was lower than that in the sham operation group (P<0.05), but 50 mg/kg cromolyn sodium group had significantly higher SOD activities than the model group (P<0.05).
Cromolyn sodium can protect the myocardium against intestal ischemia-reperfusion injury and improve the cardiac function.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 06/2007; 27(5):650-3.
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ABSTRACT: Dose calculation of radionuclide internal irradiation is a hot topic and difficulty of nuclear medical researches. This study was to calculate the focus absorption dose of 153Sm-EDTMP with the Monte Carlo EGS4 method for treatment of bone metastases from nasopharyngeal carcinoma or breast cancer, and investigate the relationship between the focus absorption dose and painkilling effect of 153Sm-EDTMP.
Four patients with multiple bone metastases from nasopharyngeal or breast carcinoma and suffered from grade IV bone pain were treated with radionuclide internal irradiation of 153Sm-EDTMP. The absorption dose and dose distribution of bone metastases and other targeted organs were calculated with MC EGS4 program based on the time-order SPECT/CT scanning and the measurement of the radioactivity in the urine accumulation. The release of bone pain and the improvement of life quality were observed.
Bone pain of the patients was significantly alleviated to grade II for 3-4 weeks after internal 153Sm-EDTMP irradiation. The 3-dimensional absorption dose distribution image of bone metastases and targeted organs showed that the dose distribution in bone metastases was not asymmetrical. After injection of 0.65x37 MBq/kg 153Sm-EDTMP, the highest absorption dose in bone lesions was about 4.9-5.9 Gy, and the dose in the lesion margin was about 2.0 Gy. Use the highest dose as reference dose point, the relative absorption dose values of bone marrow, bone cortex, and soft tissue near lesions were 0.48-1.1 Gy, 0.51-0.85 Gy, and 0.01-0.14 Gy, respectively.
The absorption dose of bone metastases is significantly lower than treatment dose of 30 Gy after single irradiation of 153Sm-EDTMP. The painkilling effect is limited and in accordance with clinical observation.
Ai zheng = Aizheng = Chinese journal of cancer 12/2006; 25(11):1395-8.
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ABSTRACT: Three-dimensional (3D) dose calculation of radionuclide therapy for specified patients is a research interest in nuclear medicine, of which the main methods include S value calculation method, dose point kernel calculation method, and Monte Carlo (MC) simulation method. This study was to compare 3D absorbed dose calculation of 153Sm-EDTMP in treating a specified patient with bone metastasis between MC and S value methods.
A 3D dose calculation program was built based on the MC program EGS4, and the S value of nuclide 153Sm was calculated. For the specified patient with bone metastasis, 153Sm activity in excreted urine was measured at 0, 0.5, 2, 3.5, 5 and 6 h after injection of 153Sm-EDTMP. The accumulative activity is calculated by fitting measurement data. Based on the fusion SPECT/CT images of the patient, 3D absorbed dose is calculated by MC and S value methods.
The iso-dose distribution curves of MC and S value calculation results were similar, and the dose was mainly collected in the bone. According to the 2 methods, the maximum doses were 3.92 Gy and 3.71 Gy with a difference of 5%. On the dose-volume histogram of the calculation volume, D10 (the highest dose of the 10% volume) were 2.14 Gy and 2.00 Gy with a difference of 7%; D20 (the highest dose of the 20% volume) were 0.58 Gy and 0.51 Gy with a difference of 14%. In general, the data of S value calculation were smaller than the data of MC calculation.
MC and S value could be used to calculate the 3D dose of radionuclide therapy based on nuclear medical image. S value is a fast and simple method for the dose evaluation although the error of the calculation is relatively bigger.
Ai zheng = Aizheng = Chinese journal of cancer 12/2006; 25(11):1399-405.
