Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A.

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Inflammatory factors mediated the effect of air pollution on ischemic stroke: a two-step, mediation Mendelian randomization study.

OBJECTIVE: Numerous investigations have indicated a correlation between air pollution (AP) and an elevated ischemic stroke (IS) likelihood. The existing literature does not provide a consensus about the possible link between AP and IS. A two-sample Mendelian randomization (MR) analysis was utilized to systematically measure the causal link between AP and ischemic stroke. Furthermore, the mediating impact of inflammatory factors was also performed by a two-step MR. MATERIALS AND METHODS: A two-sample MR analysis was utilized to examine the AP impact on the incidence of IS. Additionally, a two-step MR approach was carried out to account for possible mediating variables. The indirect impact was determined by employing the product approach, which included multiplying the AP impact on inflammatory factors by the inflammatory factors' impacts on IS. The MR effect was identified through inverse variance-weighted (IVW) meta-analysis of each Wald Ratio. Additionally, complementary studies were conducted using the weighted median and MR-egger approaches. RESULTS: The IVW method with random effects showed that the per unit increase in genetically predicted PM2.5 was linked to the 0.362-fold elevated ischemic stroke risk (OR: 1.362, 95% CI: 1.032-1.796, p=0.029). Furthermore, the IVM technique, incorporating random effects, demonstrated that the per unit increase in genetically predicted PM2.5 was related to an elevated Interleukin (IL)-1ß risk (OR: 1.529, 95% CI: 1.191-1.963, p=0.001), IL-6 (OR: 1.498, 95% CI: 1.094-2.052, p=0.012) and IL-17 (OR: 1.478, 95% CI: 1.021-2.139, p=0.038). IL-1ß, IL-6, and IL-17 modulated the PM2.5 impact on ischemic stroke, while the proportion mediated by them was 59.5%. CONCLUSIONS: A positive correlation between genetically predicted PM2.5 levels and elevated ischemic stroke risk is mediated by IL-1ß, IL-6, and IL-17.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A.

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

[Correlation between(Pro) renin receptor levels and gender and disease severity in patients with obstructive sleep apnea syndrome].

Objective:The aim of this study is to investigate the relationship between the level of (pro) renin(P)RR in obstructive sleep apnea syndrome (OSA) patients, and the gender and disease severity of the disease.b>Method:From March 2010 to March 2018, eighty OSA patients who were treated and diagnosed in our hospital were selected as subjects. Another 20 healthy subjects were selected as the control group.Plasma soluble (pro) renin receptor ï¼»s(P)RRï¼½ levels and clinical parameters were measured in healthy subjects and OSA patients with different sex and disease severity. Result:The plasma s(P)RR concentrations were significantly higher in OSA patients than that in control group. In all patients, plasma s(P)RR concentrations increased with increasing disease levels and showed the same trend between men and women. In addition,in all patients, plasma s(P)RR concentrations were significantly positively correlated with waist-to-hip ratio, HbA1c, AHI, and oxygen desaturation index. There was a significant negative correlation between saturation (MSpO2) and minimum oxygen saturation (minSpO2) (P<0.05).In female subjects,plasma s(P)RR concentrations were significantly positively correlated with waist-to-hip ratio and AHI,but significantly negatively correlated with eGFR (P<0.05).In male subjects,plasma s(P)RR concentration was significantly positively correlated with waist-to-hip ratio,HbA1c,renin level,AHI and oxygen desaturation index, but negatively correlated with eGFR, MSpO2 and minSpO2 (P<0.05). Plasma s(P)RR concentrations were significantly reduced after treatment with nasal continuous positive airway pressure ventilator. In addition, ESS,AHI,MSpO2,minSpO2,and oxygen desaturation index were all significantly improved (P<0.05).Conclusion: Plasma s(P)RR levels in OSA patients are significantly positively correlated with the severity of the disease and can directly reflect the severity of the disease. In addition, the patient with higher waist-to-hip ratio and HbA1c, and lower eGFR can effect plasma s(P)RR levels, and may lead to OSA aggravation.

[Analysis of infants with moderate to severe laryngomalacia].

Objective:To investigate the clinical features and the treatment of moderate-severe laryngeallacia, and the application of CO2laser supraglotation in laryngeallacia.Method:Collecting the clinical data of 18 infants with moderate-to-severe laryngeallacia diagnosed in our hospital,10 cases were moderate. Eight cases were severe children; according to the classification of laryngeallacia, most of them were mixed type, including 2 cases of type Ⅱ, 3 cases of type Ⅲ, 5 cases of typeⅠ + type Ⅱ, 7 cases of typeⅡ+ type Ⅲ, and 1 case of typeⅠ+ typeⅡ + type Ⅲ. Among them, 8 patients underwent CO2laser supraglotation,10 patients underwent conservative treatment.The children underwent surgery to evaluate the improvement of laryngeal wheezing, respiration, body weight, and Diet situation. All children were followed up for 12 months.Result:Eight cases with severe laryngeallacia receving CO2laser supraglotation had rapid improvement after surgery, including laryngeal wheezing, dyspnea, and cough symptoms. They were completely cured 3 months after surgery; None of the 10 cases of moderate children were cured in 3 months, 2 cases of laryngeal wheezing and dyspnea basically disappeared in 6 months, 7 cases improved, 1 case was in the plateau stage; Despnea in 8 cases of children basically disappeared 12 months later and 2 cases with mild throat wheezing, continuing conservative treatment; The weight changes, diet and respiration were closely monitored in all 18 children. The weight of the 5 children after surgery in the 3, 6 and 12 months were significantly higher than that in the untreated children. The difference was statistically significant (P<0.05).Conclusion: Electronic laryngoscope should be taked when children are suspected of laryngeal asthma, which could help diagnose moderate-severe laryngeallacia. Follow-up should be done closely. CO2laser supraglottic surgery for severe laryngeallacia, can relieve dyspnea, throat wheezing, eating difficulties and gain weight. The surgical is safety with very slight trauma and less complications, which is worth promoting; for moderate laryngeal softening, close follow-up is recommended, most of which can be treated conservatively. If there is a change in the condition, surgery should be considered.

Metformin promotes differentiation of human bone marrow derived mesenchymal stem cells into osteoblast via GSK3ß inhibition.

OBJECTIVE: Metformin, a common and first-line drug for diabetes mellitus, is widely used in the world. Recently, many studies have documented that osteogenesis could be mediated by metformin. However, the specific mechanism by which metformin affects osteogenesis has not been clearly identified. Therefore, the aim of this study is to evaluate the role of GSK3ß in metformin-induced osteogenic differentiation of mesenchymal stem cells (MSCs). MATERIALS AND METHODS: Osteoblast-marker genes, including Col-1, OCN, and RUNX2, were measured by RT-PCR in differentiated MSCs treated with Metformin. Osteogenic differentiation viability was measured by Alkaline phosphatase (ALP) assays and Alizarin Red Staining. The expression of GSK3ß, ß-catenin and AMPK were measured by Western blotting in MSCs treated with metformin. RESULTS: We found that metformin at 100 µM significantly promoted osteogenic differentiation of human mesenchymal stem cells (hBMSCs). Next, we showed that GSK3ß and Wnt signaling pathway are involved in metformin-induced osteogenic differentiation of hBMSCs. Furthermore, osteogenic differentiation of hBMSCs induced by metformin could be eliminated by inhibiting phosphorylation of GSK3ß. CONCLUSIONS: The data suggested that metformin promoted the osteoblast differentiation of MSCs by, at least partly, inhibiting GSK3ß activity. Additionally, we also found that AMPK plays an essential role in the inhibition of GSK3ß by metformin.

URG4-silencing suppresses cell proliferation in nasopharyngeal carcinoma through induction of apoptosis.

OBJECTIVE: To investigate the expression and function of up-regulator of gene-4 (URG4) in nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS: Fresh NPC tumor tissue samples with paired adjacent normal nasopharyngeal tissues samples of 9 NPC patients were collected from NPC curative resection surgery. NPC cell lines (CNE1, CNE2 and HONE1) were cultured. Lentivirus-mediated URG4-specific short hairpin RNA (shRNA) stable transfection was done. The effect of URG4 on CNE4 and HONE1 cells viability was determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The plate-colony-formation assay was performed. Apoptosis analysis was done by flow cytometry. The expression levels of protein and RNA were detected by Western blotting and quantitative polymerase chain reaction (qPCR). RESULTS: We determined the expression of URG4/URGCP in NPC tissues and cell lines using qPCR analysis and found it was significantly upregulated in NPC. After that, stable URG4-silencing NPC cells were constructed by transfection with lentivirus-mediated shRNA. Functionally analyses indicated that knockdown of URG4 significantly impaired cell viability and colony formation ability, as confirmed by MTT and colony formation assays. Furthermore, URG4-silencing NPC cells showed more cells in the stage of early and late apoptosis compared with controls by flow cytometry assay. Western blot analysis further confirmed that knockdown of URG4 enhanced the expression of cleaved caspase-3, cleaved PARP and Bax, while decreased the expression of Bcl-2 and survivin. CONCLUSIONS: URG4/URGCP might play an essential role in NPC cell growth and proliferation and its silencing might be as a potential therapeutic target for NPC.

MRI-guided radiotherapy for head and neck cancer: initial clinical experience.

PURPOSE: To report a single-institutional experience with the use of magnetic resonance imaging (MRI)-guided radiotherapy for cancers of the head and neck. MATERIALS AND METHODS: Between October 2014 and October 2016, 18 patients with newly diagnosed cancers of the head and neck were prospectively enrolled on an institutional registry trial investigating the feasibility and efficacy of external-beam radiotherapy delivered using on-board MRI. All patients had biopsy-proven evidence of malignancy, measurable disease, and the ability to provide consent. None had previously received any treatment. Median dose was 70 Gy (range 54-70 Gy). MRI scans were obtained as part of an image-guided registration protocol for alignment prior to and during each treatment. Concurrent chemotherapy was administered to 14 patients (78%). Patient-reported outcomes were assessed using the University of Washington quality of life instrument. RESULTS: Seventeen of 18 patients completed the planned intensity-modulated radiotherapy (IMRT) treatment of which 15 (83%) had a complete response and 2 (11%) had a partial response based on initial post-therapy positron emission tomography (PET) at 3 months. The 1-year estimates of progression-free survival, overall survival, and local-regional control were 95, 96, and 95%, respectively. There were no treatment-related fatalities. The incidence of grade 3+ acute toxicity was 44%. The proportion of patients rating their health-related quality of life as "very good" or "outstanding" at 6 months and 1 year after completion of radiation therapy was 60 and 70%, respectively. CONCLUSIONS: MRI-guided radiotherapy achieves clinical outcomes comparable to contemporary series reporting on IMRT for head and neck cancer.

Helical tomotherapy with simultaneous integrated boost dose painting for the treatment of synchronous primary cancers involving the head and neck.

OBJECTIVE: To demonstrate the feasibility of helical tomotherapy (HT)-based intensity-modulated radiotherapy (IMRT) for the treatment of synchronous primary cancers arising from the head and neck. METHODS: 14 consecutive patients with histologically proven squamous cell carcinoma of the head and neck were determined to have a second primary cancer in the upper aerodigestive tract on further evaluation and were treated with HT using simultaneous integrated boost IMRT. Megavoltage CT scans were acquired daily as part of an image-guided registration protocol. Concurrent platinum-based systemic therapy was given to nine patients (64%). RESULTS: HT resulted in durable local control in 21 of the 28 primary disease sites irradiated, including a complete clinical and radiographic response initially observed at 17 of the 20 sites with gross tumour. The mean displacements to account for interfraction motion were 2.44 ± 1.25, 2.92 ± 1.09 and 2.31 ± 1.70 mm for the medial-lateral (ML), superior-inferior (SI) and anteroposterior (AP) directions, respectively. Table shifts of >3 mm occurred in 19%, 20% and 22% of the ML, SI and AP directions, respectively. The 2-year estimates of overall survival, local-regional control and progression-free survival were 58%, 73% and 60%, respectively. CONCLUSION: The effectiveness of HT for the treatment of synchronous primary cancers of the head and neck was demonstrated. ADVANCES IN KNOWLEDGE: HT is a feasible option for synchronous primary cancers of the head and neck and can result in long-term disease control with acceptable toxicity in appropriately selected patients.

Evaluation of hippocampus dose for patients undergoing intensity-modulated radiotherapy for nasopharyngeal carcinoma.

OBJECTIVE: To evaluate the dose received by the hippocampus among patients undergoing intensity-modulated radiotherapy (IMRT) for nasopharyngeal cancer. METHODS: 10 patients with biopsy-proven, locally advanced nasopharyngeal cancer constituted the study population. The total prescribed dose to the planning target volume (PTV) was 70 Gy (D95%) delivered in 2.12-Gy daily fractions using IMRT. Using established anatomical guidelines, MRI co-registration and the assistance of a board-certified neuroradiologist, the right and left hippocampi were delineated on axial imaging from the CT scan obtained at simulation for each patient beginning at the most anterior portion of the lateral ventricle. IMRT treatment plans were generated without dose-volume constraints to the hippocampus. A range of dose-volume statistics was calculated. RESULTS: The mean hippocampus volume was 6.01 ± 2.61 cm(3). The mean V20 was 72.2%; V40 was 22.0%; V50 was 10.2%; and V60 was 5.5%. The average mean, minimum and maximum hippocampus doses were 30.27 Gy (range, 19.08-47.99 Gy); 17.54 Gy (range, 11.66-33.17 Gy); and 54.95 Gy (range, 35.59-75.57 Gy), respectively. The hippocampus received a maximum dose exceeding 70 Gy in 30% of cases. CONCLUSION: Our dosimetric analysis suggests that, for patients undergoing IMRT for nasopharyngeal cancer, the hippocampus routinely receives significantly high doses. ADVANCES IN KNOWLEDGE: The hippocampus receives a fair amount of incidental radiation during treatment for nasopharyngeal cancer. Given the importance of this structure with respect to memory and neurocognitive function, consideration should be given to identifying the hippocampus as a critical organ at risk in the IMRT optimization process.

Clinical-dosimetric relationship between lacrimal gland dose and ocular toxicity after intensity-modulated radiotherapy for sinonasal tumours.

OBJECTIVE: To characterise the relationship between lacrimal gland dose and ocular toxicity among patients treated by intensity-modulated radiotherapy (IMRT) for sinonasal tumours. METHODS: 40 patients with cancers involving the nasal cavity and paranasal sinuses were treated with IMRT to a median dose of 66.0 Gy. Toxicity was scored using the Radiation Therapy Oncology Group morbidity criteria based on conjunctivitis, corneal ulceration and keratitis. The paired lacrimal glands were contoured as organs at risk, and the mean dose, maximum dose, V10, V20 and V30 were determined. Statistical analysis was performed using logistic regression and the Akaike information criterion (AIC). RESULTS: The maximum and mean dose to the ipsilateral lacrimal gland were 19.2 Gy (range, 1.4-75.4 Gy) and 14.5 Gy (range, 11.1-67.8 Gy), respectively. The mean V10, V20 and V30 values were 50%, 25% and 17%, respectively. The incidence of acute and late Grade 3+ toxicities was 23% and 19%, respectively. Based on logistic regression and AIC, the maximum dose to the ipsilateral lacrimal gland was identified as a more significant predictor of acute toxicity (AIC, 53.89) and late toxicity (AIC, 32.94) than the mean dose (AIC, 56.13 and 33.83, respectively). The V20 was identified as the most significant predictor of late toxicity (AIC, 26.81). CONCLUSION: A dose-response relationship between maximum dose to the lacrimal gland and ocular toxicity was established. Our data suggesting a threshold relationship may be useful in establishing dosimetric guidelines for IMRT planning that may decrease the risk of acute and late lacrimal toxicities in the future. ADVANCES IN KNOWLEDGE: A threshold relationship between radiation dose to the lacrimal gland and ocular toxicity was demonstrated, which may aid in treatment planning and reducing the morbidity of radiotherapy for sinonasal tumours.

Intensity-modulated radiotherapy for nasopharyngeal carcinoma: improvement of the therapeutic ratio with helical tomotherapy vs segmental multileaf collimator-based techniques.

OBJECTIVES: The aim of the study was to compare differences in dosimetric, clinical and quality-of-life end points among patients treated with helical tomotherapy (HT) and segmental multileaf collimator (SMLC)-based intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma. METHODS: From June 2005 to August 2009, 30 consecutive patients were treated with IMRT for nasopharyngeal carcinoma to a dose of 70 Gy. 14 patients (47%) were treated using HT and 16 (53%) were treated using SMLC-based IMRT. 28 patients (93%) received concurrent chemotherapy. The patients were evenly balanced between the two radiotherapy groups with respect to clinical and pathological characteristics. Median follow-up was 30 months (range, 6-62 months). RESULTS: The 2-year estimates of overall survival, local-regional control and progression-free survival were 81%, 87% and 82%, respectively. There were no significant differences in any of these end points with respect to IMRT technique (p>0.05 for all). Dosimetric analysis revealed that patients treated by HT had significantly improved salivary sparing with respect to mean dose (27.3 vs 34.1 Gy, p=0.03) and volume receiving greater than or equal to 30 Gy (31.7% vs 47.3%, p=0.01) to the contralateral (spared) parotid gland. The incidence of Grade 3+ late xerostomia was 13 and 7% among patients treated with SMLC-based IMRT and HT, respectively (p=0.62). The corresponding proportion of patients who subjectively reported "too little" or "no" saliva at final follow-up was 38% and 7%, respectively (p=0.04). CONCLUSION: The superior dosimetric outcome observed with HT appeared to translate into moderately improved clinical outcomes with respect to salivary sparing. Prospective trials are needed to validate this gain in the therapeutic ratio.

Changes in position and volume of lung cancer target volumes during stereotactic body radiotherapy (SBRT): is image guidance necessary?

The purpose of this study was to analyze inter- and intra-fractional changes in tumor volume with respect to both spatial and volumetric parameters among patients treated by SBRT for lung cancer. Twelve patients (13 tumors) were treated by SBRT with abdominal compression in 3-5 fractions over a 2 week period to a median dose of 60 Gy (range, 48 to 60 Gy). Kilovoltage cone-beam CT (CBCT) was obtained prior to the delivery of each fraction as well as intra-fractionally yielding a total of 55 CBCT scans. All CBCT scans were registered with the planning CT for target alignment and shifts were recorded and analyzed. Retrospectively, gross tumor volume (GTV) was contoured on all CBCT images and compared to initial planning volumes; positional differences were evaluated utilizing directional and vector analysis. Shifts greater than 5 mm were applied inter-fractionally in 6.8% (lateral), 29.5% (longitudinal), and 6.8% (vertical) of all delivered treatments. Using a 10 mm threshold, the corresponding percentages were 2.3%, 13.6%, and 2.3%, respectively. Across all fractions, the calculated inter-fractional shift vectors ranged from 0 to 31.2 mm, with 40.9%, 15.9%, and 11.4% of all fractions having shift vectors≥5 mm, ≥10 mm, and ≥20 mm, respectively. Intra-fractional shifts were also evaluated and found negligible in a small portion of patients evaluated. The mean overall reduction in GTV was 21.1% during SBRT. Significant changes in both position and volume occur during SBRT for lung cancer. Shifts (particularly in the superior-inferior axis) may exceed applied margins and compromise target coverage. Due to the extreme hypofractionation associated with SBRT, inter-fractional image guidance is necessary.

Comparison of IMRT techniques in the radiotherapeutic management of head and neck cancer: is tomotherapy "better" than step-and-shoot IMRT?

Currently, the most common method of delivering intensity-modulated radiotherapy (IMRT) is through step-and-shoot, segmental multi-leaf collimator (SMLC)-based techniques. Although rotational delivery methods such as helical tomotherapy (HT) have been proposed as offering advantages in the treatment of head and neck cancer, a lack of clinical data exists on its potential utility. This study compared dosimetric, clinical, and quality-of-life endpoints among 149 patients treated by HT and SMLC-IMRT for head and neck cancer. Dosimetric analysis revealed that the use of HT resulted in significant improvements with respect to mean dose (23.5 versus 27.9 Gy, p = 0.03) and V30 (30.1 versus 43.9 Gy, p = 0.01) to the contralateral (spared) parotid gland. However, the incidence of grade 3+ xerostomia in the late setting was 10% and 8% among patients treated by HT and SMLC-IMRT, respectively (p = 0.46). There were no significant differences in any of the quality of life endpoints among patients treated by HT and SMLC-IMRT (p > 0.05, for all). Acknowledging the biases inherent in this retrospective analysis, we found that the dosimetric advantages observed with HT compared to SMLC-IMRT failed to translate into significant improvements in clinical outcome. Prospective studies are needed to further evaluate how HT may affect the therapeutic ratio.

Overstaging of cartilage invasion by multidetector CT scan for laryngeal cancer and its potential effect on the use of organ preservation with chemoradiation.

OBJECTIVE: The two currently acceptable treatment options for locally advanced laryngeal cancer are total laryngectomy and organ preservation using chemoradiation. To facilitate therapeutic decision making, the accurate pre-treatment evaluation of cartilage invasion is of paramount importance. The purpose of this study was to evaluate the positive predictive value (PPV) and negative predictive value (NPV) of detecting neoplastic cartilage invasion in laryngeal cancer patients using fast-speed multidetector CT (MDCT). METHODS: 61 consecutive patients with clinically staged T3 or T4 squamous cell carcinoma of the larynx or hypopharynx who underwent total laryngectomy were analysed. All patients had MDCT of the neck within 2 weeks prior to surgery. Central radiographic and pathological review was performed in an attempt to correlate findings. MDCT invasion of cartilage was graded based on objective criteria. RESULTS: MDCT scan was found to have a PPV of 78% and an NPV of 100% for detection of invasion through cartilage, with sensitivity being 100% and specificity 96%. For detection of any cartilage invasion (minor, major or through cartilage invasion), PPV and NPV were 63% and 92%, respectively. The sensitivity was 85% and specificity was 75%. For the detection of tumour invasion through cartilage or major cartilage invasion, MDCT scan had a PPV of 53% and an NPV of 95%. 47% (9/19) patients were down-staged from T4 to T3 after central pathology review. CONCLUSION: The low PPV for cartilage destruction using MDCT suggests that a significant proportion of patients who were treated by total laryngectomy could have been appropriately offered organ preservation if more accurately staged at initial diagnosis.

Intensity-modulated radiotherapy increases dose to the brachial plexus compared with conventional radiotherapy for head and neck cancer.

OBJECTIVE: The preferential use of intensity-modulated radiotherapy (IMRT) over conventional radiotherapy (CRT) in the treatment of head and neck cancer has raised concerns regarding dose to non-target tissue. The purpose of this study was to compare dose-volume characteristics with the brachial plexus between treatment plans generated by IMRT and CRT using several common treatment scenarios. METHOD: The brachial plexus was delineated on radiation treatment planning CT scans from 10 patients undergoing IMRT for locally advanced head and neck cancer using a Radiation Therapy Oncology Group-endorsed atlas. No brachial plexus constraint was used. For each patient, a conventional three-field shrinking-field plan was generated and the dose-volume histogram (DVH) for the brachial plexus was compared with that of the IMRT plan. RESULTS: The mean irradiated volumes of the brachial plexus using the IMRT vs the CRT plan, respectively, were as follows: V50 (18±5 ml) vs (11±6 ml), p = 0.01; V60 (6±4 ml) vs (3±3 ml), p = 0.02; V66 (3±1 ml) vs (1±1 ml), p = 0.04, V70 (0±1 ml) vs (0±1 ml), p = 0.68. The maximum point dose to the brachial plexus was 68.9 Gy (range 62.3-78.7 Gy) and 66.1 Gy (range 60.2-75.6 Gy) for the IMRT and CRT plans, respectively (p = 0.01). CONCLUSION: Dose to the brachial plexus is significantly increased among patients undergoing IMRT compared with CRT for head and neck cancer. Preliminary studies on brachial plexus-sparing IMRT are in progress.

Brown-Séquard syndrome due to penetrating injury by an iron fence point.

STUDY DESIGN: Case report. OBJECTIVES: To present an unusual type of penetrating objects causing Brown-Séquard syndrome (BSS) and its clinical character. SETTING: Department of Orthopaedic Surgery, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, PR China. METHODS: A 54-year-old man fell from a height of 4 m onto an iron fence, and a sharp iron fence point penetrated the right side of his back. He developed left-sided BSS. Both X-ray film and computed tomography scanning of the thoracic spine showed a right vertebral plate of Th5 fracture and metal fragments inclining through the posterior and left lateral of the spinal canal. Emergency decompressive laminectomy and removal of the foreign metal piece were performed. No improvement in neurological function was observed 10 days after surgery, and thus hyperbaric oxygen treatment was initiated twice a day for the next 1 month. RESULTS: Forty days after surgery, his bladder function returned to normal. The motor deficit had regressed and he could walk without assistance 70 days after the operation. One year later, his lower extremity functions recovered almost completely, except for slight numbness on the right side. CONCLUSION: As far as we know, on the basis of existing literature, the injury mechanism to BSS by a sharp iron fence point has not been reported so far. The satisfactory recovery after injury may in part be attributed to timely surgery and continuing hyperbaric oxygen treatment.

The evaluation of 6 and 18 MeV electron beams for small animal irradiation.

A small animal irradiator is critical for providing optimal radiation dose distributions for pre-clinical animal studies. This paper focuses on the evaluation of using 6 or 18 MeV electron beams as small animal irradiators. Compared with all other prototypes which use photons to irradiate small animals, an electron irradiator has many advantages in its shallow dose distribution. Two major approaches including simulation and measurement were used to evaluate the feasibility of applying electron beams in animal irradiation. These simulations and measurements were taken in three different fields (a 6 cm x 6 cm square field, and 4 mm and 30 mm diameter circular fields) and with two different energies (6 MeV and 18 MeV). A PTW Semiflex chamber in a PTW-MP3 water tank, a PTW Markus chamber type 23343, a PTW diamond detector type 60003 and KODAK XV films were used to measure PDDs, lateral beam profiles and output factors for either optimizing parameters of Monte Carlo simulation or to verify Monte Carlo simulation in small fields. Results show good agreement for comparisons of percentage depth doses (