Cervical spine osteoradionecrosis or bone metastasis after radiotherapy for nasopharyngeal carcinoma? The MRI-based radiomics for characterization.

BACKGROUND: To develop and validate an MRI-based radiomics nomogram for differentiation of cervical spine ORN from metastasis after radiotherapy (RT) in nasopharyngeal carcinoma (NPC). METHODS: A radiomics nomogram was developed in a training set that comprised 46 NPC patients after RT with 95 cervical spine lesions (ORN, n = 51; metastasis, n = 44), and data were gathered from January 2008 to December 2012. 279 radiomics features were extracted from the axial contrast-enhanced T1-weighted image (CE-T1WI). A radiomics signature was created by using the least absolute shrinkage and selection operator (LASSO) algorithm. A nomogram model was developed based on the radiomics scores. The performance of the nomogram was determined in terms of its discrimination, calibration, and clinical utility. An independent validation set contained 25 consecutive patients with 47 lesions (ORN, n = 25; metastasis, n = 22) from January 2013 to December 2015. RESULTS: The radiomics signature that comprised eight selected features was significantly associated with the differentiation of cervical spine ORN and metastasis. The nomogram model demonstrated good calibration and discrimination in the training set [AUC, 0.725; 95% confidence interval (CI), 0.622-0.828] and the validation set (AUC, 0.720; 95% CI, 0.573-0.867). The decision curve analysis indicated that the radiomics nomogram was clinically useful. CONCLUSIONS: MRI-based radiomics nomogram shows potential value to differentiate cervical spine ORN from metastasis after RT in NPC.

Set-up error and dosimetric analysis of HexaPOD evo RT 6D couch combined with cone beam CT image-guided intensity-modulated radiotherapy for primary malignant tumor of the cervical spine.

PURPOSE: To investigate the set-up error and consequent dosimetric change in HexaPOD evo RT 6D couch under image-guided intensity-modulated radiotherapy (IG-IMRT) for primary malignant tumor of the cervical spine. METHODS: Ten cases with primary malignant tumor of the cervical spine were treated with intensity-modulated radiotherapy (IMRT) in our hospital from August 2013 to November 2014. The X-ray volumetric images (XVI) were scanned and obtained by cone-beam CT (CBCT). The six directions (6D) of set-up errors of translation and rotation were obtained by planned CT image registration. HexaPOD evo RT 6D couch made online correction of the set-up error, and then the CBCT was conducted to obtain the residual error. RESULTS: We performed set-up error and dosimetric analysis. First, for the set-up error analysis, the average error in three translation directions of 6D set-up error of the primary tumor of the cervical spine was <2 mm, whereas the single maximum error (absolute value) is 7.0 mm. Among average errors of rotation direction, Rotation X (RX) direction 0.67° ± 0.04°, Rotation Y (RY) direction 1.06° ± 0.06°, Rotation Z (RZ) direction 0.78° ± 0.05°; and the single maximum error in three rotation directions were 2.8°, 3.8°, and 2.9°, respectively. On three directions (X, Y, Z axis), the extended distance from clinical target volume (CTV) to planning target volume (PTV) was 3.45, 3.17, and 3.90 mm by calculating, respectively. Then, for the dosimetric analysis, the parameters, including plan sum PTV D98 and D95, planning gross tumor volume D98 and D95, V100% of the plan sum were significantly lower than the treatment plan. Moreover, Dmax of the spinal cord was significantly higher than the treatment plan. CONCLUSION: 6D set-up error correction system should be used for accurate position calibration of precise radiotherapy for patients with malignant tumor of the cervical spine.

Muscle fiber conduction velocity and EMG amplitude of the upper trapezius muscle in healthy subjects after low-level laser irradiation: a randomized, double-blind, placebo-controlled, crossover study.

Although low-level laser therapy (LLLT) is an important resource for the treatment of non-specific neck pain patients, the dose which presents the greatest therapeutic potential for the treatment of this pathology is still unclear. The present study aimed to evaluate the immediate effect of LLLT on the muscle fiber conduction velocity (MFCV) and electromyographic activity (EMG) of the upper trapezius (UT) muscle in healthy individuals. A total of 20 healthy subjects were enrolled in a randomized, double-blind, crossover study. Active LLLT (820 nm wavelength, 30 mW, energy total 18 J) or placebo LLLT (pLLLT) was delivered on the UT muscle. Each subject was subjected to a single session of active LLLT and pLLLT. Surface electromyography (sEMG) signal of the UT muscle was recorded during five different step contractions of shoulder elevation force (10-30% maximal voluntary contraction) pre- and post-LLLT irradiation. The values of MFCV and sEMG global amplitude (RMSG) were used to calculate the effects of LLLT. The results showed no difference in the MFCV comparing the LLLT and pLLLT groups (F = 0.72 p = 0.39, η p2 = 0.004). However, a significant difference was observed in the RMSG between the LLLT and pLLLT (F 1,2 = 16.66; P < 0.0001, η p2 = 0.09). Individuals who received active LLLT presented a significant decrease in RMSG after laser application (F = 61.28; p < 0.0001, η p2 = 0.43). In conclusion, the 820 nm LLLT, with energy total of 18 J, did not alter the MFCV but significantly reduced the sEMG signal amplitude of the upper trapezius muscle in healthy subjects to a level of up to 30% of maximal voluntary contraction.

Influences of different lower cervical bone graft heights on the size of the intervertebral foramen: multiple planar dynamic measurements with laser scanning.

The aim of this study is to evaluate the influences of different bone graft heights on the size of the intervertebral foramen, which will help determine the optimal graft height in clinical practice. Six fresh adult cadavers were used, with the C5-C6 vertebral column segment defined as the functional spinal unit (FSU). After discectomy, the C5/6 intervertebral height was set as the baseline height (normal disc height). We initially used spiral computed tomography (CT) to scan and measure the middle area of the intervertebral foramen when at the baseline height. Data regarding the spatial relationship of C5-C6 were subsequently collected with a laser scanner. Grafting with four different sized grafts, namely, grafts of 100, 130, 160, and 190% of the baseline height, was implanted. Moreover, we scanned to display the FSU in the four different states using Geomagic8.0 studio software. Multiple planar dynamic measurements (MPDM) were adopted to measure the intervertebral foramen volume, middle area, and areas of internal and external opening. MPDM with a laser scanner precisely measured the middle area of the intervertebral foramen as spiral CT, and it is easy to simulate the different grafts implanted. With the increase of the bone graft height, the size of the intervertebral foramen began to decrease after it increased to a certain point, when grafts of 160% of the baseline height implanted. MPDM of the intervertebral foramens with laser scanning three-dimensional (3D) reconstitution are relatively objective and accurate. The recommended optimal graft height of cervical spondylosis is 160% of the mean height of adjacent normal intervertebral spaces.

Intraoperative radiation exposure in spinal scoliosis surgery for pediatric patients using the O-arm® imaging system.

PURPOSE: The O-arm® navigation system allows intraoperative CT imaging that can facilitate highly accurate instrumentation surgery, but radiation exposure is higher than with X-ray radiography. This is a particular concern in pediatric surgery. The purpose of this study is to examine intraoperative radiation exposure in pediatric spinal scoliosis surgery using O-arm. METHODS: The subjects were 38 consecutive patients (mean age 12.9 years, range 10-17) with scoliosis who underwent spinal surgery with posterior instrumentation using O-arm. The mean number of fused vertebral levels was 11.0 (6-15). O-arm was performed before and after screw insertion, using an original protocol for the cervical, thoracic, and lumbar spine doses. RESULTS: The average scanning range was 6.9 (5-9) intervertebral levels per scan, with 2-7 scans per patient (mean 4.0 scans). Using O-arm, the dose per scan was 92.5 (44-130) mGy, and the mean total dose was 401 (170-826) mGy. This dose was 80.2% of the mean preoperative CT dose of 460 (231-736) mGy (P = 0.11). The total exposure dose and number of scans using intraoperative O-arm correlated strongly and significantly with the number of fused levels; however, there was no correlation with the patient's height. CONCLUSIONS: As the fused range became wider, several scans were required for O-arm, and the total radiation exposure became roughly the same as that in preoperative CT. Use of O-arm in our original protocol can contribute to reduction in radiation exposure.

Hypopharyngeal and upper esophageal ulceration after cervical spine radiotherapy concurrent with crizotinib.

Herein, the authors describe the case of a 31-year-old female patient with primary metastatic adenocarcinoma of the lung referred for radiation therapy of newly diagnosed intramedullary spinal cord metastasis at C4/5 and an adjacent osteolytic lesion. Radiotherapy of the cervical spine level C3 to C5, including the whole vertebra, was performed with 30 Gy in 10 fractions. The patient's systemic therapy with crizotinib 250 mg twice daily was continued. After 8 fractions of radiation the patient developed increasing dysphagia. Ulceration of the hypopharynx and the upper esophagus were obvious in esophagoscopy and CT. Hospitalization for analgesia and percutaneous endoscopic gastrostomy (PEG) was required. First oral intake was possible 3 weeks after the onset of symptoms. The early onset, severity, and duration of mucositis seemed highly unusual in this case. A review of the literature failed to identify any reference to increased mucositis after radiation therapy concurrent with crizotinib, although references to such an effect with other tyrosine kinase inhibitors (TKI) were found. Nevertheless, the authors presume that a considerable risk of unexpected interactions exists. When crizotinib and radiotherapy are combined, heightened attention toward intensified reactions seems to be warranted.

Clinical indications and radiation doses to the conceptus associated with CT imaging in pregnancy: a retrospective study.

OBJECTIVE: To perform an internal audit at a university hospital with the aim of evaluating the number, clinical indication and operating procedure of computed tomography (CT) performed on pregnant patients and of estimating the radiation doses to the conceptus. METHODS: A retrospective review was conducted of all CT examinations performed in a single centre on pregnant patients between January 2008 and July 2013. The radiation doses to the conceptus were estimated. The results were compared with published data. RESULTS: The number of CT examinations during pregnancy increased from 3-4 per year in 2008-2011 to 11 per year in 2012. The mean estimated conceptus radiation dose was considered negligible for CT of the head and cervical spine, being less than 0.01 mGy, and for CT of the chest, less than 0.1 mGy. The estimated conceptus radiation dose from abdominopelvic CT was on average 28.7 mGy (range 6.7-60.5 mGy). CONCLUSIONS: The number of CT scans of pregnant patients increased threefold during the last few years. Most clinical indications and doses were in line with good clinical practice and literature; only in two cases the dose to the conceptus was higher than 50 mGy. KEY POINTS: • An increase in CT imaging of pregnant patients is of concern. • Clinical indications were in line with good practice. • Estimated conceptus doses were lower or similar to published data. • Internal guidelines for appropriate use of imaging during pregnancy should be established.

Evaluation of a dedicated MDCT protocol using iterative image reconstruction after cervical spine trauma.

AIM: To evaluate radiation exposure for 64-row computed tomography (CT) of the cervical spine comparing two optimized protocols using filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR), respectively. MATERIALS AND METHODS: Sixty-seven studies using FBP (scanner 1) were retrospectively compared with 80 studies using ASIR (scanner 2). The key scanning parameters were identical (120 kV dose modulation, 64 × 0.625 mm collimation, pitch 0.531:1). In protocol 2, the noise index (NI) was increased from 5 to 25, and ASIR and the high-definition (HD) mode were used. The scan length, CT dose index (CTDI), and dose-length product (DLP) were recorded. The image quality was analysed subjectively by using a three-point scale (0; 1; 2), and objectively by using a region of interest (ROI) analysis. Mann-Whitney U and Wilcoxon's test were used. RESULTS: In the FBP group, the mean CTDI was 21.43 mGy, mean scan length 186.3 mm, and mean DLP 441.15 mGy cm. In the ASIR group, the mean CTDI was 9.57 mGy, mean scan length 195.21 mm, and mean DLP 204.23 mGy cm. The differences were significant for CTDI and DLP (p < 0.001) and scan length (p = 0.01). There was no significant difference in the subjective image quality (p > 0.05). The estimated mean effective dose decreased from 2.38 mSv (FBP) to 1.10 mSv (ASIR). CONCLUSION: The radiation dose of 64-row MDCT can be reduced to a level comparable to plain radiography without loss of subjective image quality by implementation of ASIR in a dedicated cervical spine trauma protocol. These results might contribute to an improved relative risk-to-benefit ratio and support the justification of CT as a first-line imaging tool to evaluate cervical spine trauma.

Comparison of adult and child radiation equivalent doses from 2 dental cone-beam computed tomography units.

INTRODUCTION: With the advent of cone-beam computed tomography (CBCT) scans, there has been a transition toward these scans' replacing traditional radiographs for orthodontic diagnosis and treatment planning. Children represent a significant proportion of orthodontic patients. Similar CBCT exposure settings are predicted to result in higher equivalent doses to the head and neck organs in children than in adults. The purpose of this study was to measure the difference in equivalent organ doses from different scanners under similar settings in children compared with adults. METHODS: Two phantom heads were used, representing a 33-year-old woman and a 5-year-old boy. Optically stimulated dosimeters were placed at 8 key head and neck organs, and equivalent doses to these organs were calculated after scanning. The manufacturers' predefined exposure settings were used. RESULTS: One scanner had a pediatric preset option; the other did not. Scanning the child's phantom head with the adult settings resulted in significantly higher equivalent radiation doses to children compared with adults, ranging from a 117% average ratio of equivalent dose to 341%. Readings at the cervical spine level were decreased significantly, down to 30% of the adult equivalent dose. When the pediatric preset was used for the scans, there was a decrease in the ratio of equivalent dose to the child mandible and thyroid. CONCLUSIONS: CBCT scans with adult settings on both phantom heads resulted in higher radiation doses to the head and neck organs in the child compared with the adult. In practice, this might result in excessive radiation to children scanned with default adult settings. Collimation should be used when possible to reduce the radiation dose to the patient. While CBCT scans offer a valuable tool, use of CBCT scans should be justified on a specific case-by-case basis.

CT-myelography for high-dose irradiation of spinal and paraspinal tumors with helical tomotherapy: revival of an old tool.

BACKGROUND AND PURPOSE: High-dose irradiation or reirradiation of spinal and paraspinal tumors is a challenge particularly in the presence of metal artifacts after surgery. Image-guided advanced intensity-modulated radiotherapy delivers high-dose radiation to the tumor sparing the spinal cord. Precise delineation of the spinal cord is necessary treating para- and intraspinal tumors with a sufficient dose. PATIENTS AND METHODS: The use of myelo-CT was evaluated in 23 patients with spinal and paraspinal tumors. All patients had had previous surgery with metal implants in the radiation area. All patients had an indication for high-dose irradiation. Treatment planning was performed using nonenhanced and contrast-enhanced myelo-CT in the same position and immobilization and both CT scans were matched. Treatment was performed by using a tomotherapy treatment unit. RESULTS: Contouring of the myelon in all slices of the myelo-CT was possible in 20 of 23 patients. All these patients were treated with doses of median 69.4 Gy in 2 Gy/1.8 Gy single doses using daily image guidance. One patient received an integrated boost with a TD/SD of 70/2.3 Gy. No side effects have been observed so far during a median follow-up of 15.5 months. No separation between tumor and myelon could be observed in 3 patients. CONCLUSION: Myelo-CT offers a distinct delineation of the myelon and the paraspinal tumor in case of artifacts due to metal implants after surgery. Using this tool in combination with advanced image guidance and IMRT techniques, patients with relatively radioresistent paraspinal tumors might have the chance of improved local control using higher target doses.

[Analysis of the efficacy of low-frequency pulse therapy in the combination with radon baths for the treatment of patients with different variants of the clinical course of cervical dorsopathy].

The authors present the results of analysis of combined physiobalneotherapy in the patients with neurological manifestations of degenerative lesions in the cervical spine with special reference to the clinical form of the disease. The use of unified criteria for the assessment of cervico-brachial pain syndrome and clinico-neuropsychological status of the patients in conjunction with auxiliary research techniques made it possible to demonstrate the high efficacy of the treatment using low-frequency pulse therapy supplemented by the application of radon baths. The best therapeutic effect was achieved in a group of patients presenting with cervico-brachial syndrome treated during the periods of exacerbation of cervical spine osteochondrosis. A less pronounced positive effect was documented in the group having the recurrent clinical course of cervico-brachial pain syndrome due to degenerative and dystrophic lesions in the cervical spine and diskopathy. The difference between the responses of the two groups of patients can be accounted for not only by the severity of degenerative lesions in the cervical spine but also by the changes in their psychoemotional sphere.

Optimization of the scan length of head traumas on the pediatric and adult CT scan and proposition of a new acquisition limit.

To propose a new method of reducing the scan length of head trauma while keeping the diagnostic efficiency of the examination in order to develop DRL in an African context. This is a retrospective single-center study including 145 patients who had cranial examinations on a 64-barettes scanner. All head trauma cases were selected. The interpretations of these CT scanners by the three radiologists of the service were noted to determine the acquisition limit. All patient acquisition lengths have been recorded. The acquisition limit for head trauma ended in clinical routine at cervical spine 4 (C4). The average scan length was 23.03 cm. Out of the CT scan results for 145 patients, only 2 (1.37%) had a C3 level cervical spine fracture and 2 (1.37%) at C4. By respecting the principles of radiation protection, this result has shown us that it is possible to limit the acquisition length of the CT scanners indicated for head trauma. The limit of the optimized scan length that we proposed is at cervical spine 2 (98.62%). Now, all head trauma are limited on cervical vertebra 2 in our hospital. The use of this new method is beneficial when the clinical indication of the examination and the type of trauma (multi-trauma) are taken into account. Based on the principles of radiation protection and the clinical indication for the examination, reducing the scan length from C4 to C2 is an effective way to reduce the dose absorbed by the patient.

STRATEGY OF COMPUTED TOMOGRAPHY IMAGE OPTIMISATION IN CERVICAL VERTEBRAE AND NECK SOFT TISSUE IN EMERGENCY PATIENTS.

INTRODUCTION: With regards to the use of ionisation radiation in the computed tomography (CT), optimal parameters should be used to reduce the risk of incidence of secondary cancers in patients who are constantly exposed to X-rays. The aim of this study was to optimise the parameters used in CT scan of cervical vertebrae and neck soft tissue with minimal loss of image quality in emergency patients. MATERIALS AND METHODS: In this study, the patients were divided into two groups. The first group consisted of patients scanned with default parameters and the second group scanned with optimised parameters. All the study has been implemented in emergency settings. The cases included cervical vertebrae and soft tissue protocols. Common CT dose descriptors including weighted computed tomography dose index (CTDIw), volumetric CTDI (CTDIvol), dose length product (DLP), effective dose (ED) and image noise were measured for each group. The ImpactDose program was used to estimate the organs doses. Statistical analysis was performed using Kruskal-Wallis test using SPSS software. RESULTS: There was no significant quality reduction in the optimised images. Decreasing in radiation dose parameters for the soft tissue was: kVp=16.7%, mAs=64.3% and pitch=24.1%, and for the cervical vertebrae was: kVp=16.7%, mAs=54.2% and pitch=48.3%. Consequently, decreasing these parameters reduced CTDIw=81.0%, CTDIvol=90.0% and DLP = 90.2% in the cervical vertebral protocol, as well as CTDIw=75.5%, CTDIvol=81.3% and DLP = 81.4% in the soft tissue protocol. CONCLUSION: Regarding the results, the optimised parameters in the mentioned organ scan reduce the radiation dose in the target area and the organs surrounding. Therefore, these protocols can be used for reducing the risk of cancer.

Proton therapy in pediatric skull base and cervical canal low-grade bone malignancies.

PURPOSE: To evaluate outcomes and tolerance of high-dose photon and proton therapy in the management of skull base and cervical canal primary bony malignancies in children. PATIENTS AND METHODS: Thirty children were treated postoperatively with high-dose photon-proton (29 patients) or protons-only (1 patient) radiotherapy. Twenty-six patients had chordomas (CH), 3 had low-grade chondrosarcomas (CS), and 1 had an aggressive chondroma (AC). The mean age was 12.8 years. At the time of radiation, all but 1 patient had a gross residue. The anatomic sites affected were skull base (n = 16), cervical canal (n = 1), or both (n = 13). Mean total dose was 68.4 cobalt Gray equivalents, conventionally fractionated. RESULTS: With a mean follow-up of 26.5 months, 5 of 30 children failed locally: 5 of 5 lesions were CH, 5 of 5 patients had experienced pain at presentation (p = 0.03), and 4 of 5 had cervical extension (p = 0.07). The 5-year overall survival/progression-free survival rates for CS and CH were 100%/100% and 81%/77%, respectively. Side effects were scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events v3.0. Acute toxicity ranged between 0 and 2. Late toxicity of radiotherapy was severe in 1 patient (Grade 3 auditory) and minor or mild in the rest of the population (7 patients with Grade 2 pituitary dysfunction). CONCLUSIONS: High-dose combined fractionated photon-proton therapy is well tolerated in children and allows excellent local control with minimal long-term toxicity.

Vertebral body growth after craniospinal irradiation.

PURPOSE: To estimate the effects of radiotherapy and clinical factors on vertebral growth in patients with medulloblastoma and supratentorial primitive neuroectodermal tumors treated with craniospinal irradiation (CSI) and chemotherapy. METHODS AND MATERIALS: The height of eight individual or grouped vertebral bodies (C3, C3-C4, T4, T4-T5, C6-T3, T4-T7, L3, L1-L5) was measured before and after CSI (23.4 or 36-39.6 Gy) in 61 patients. Of the 61 patients, 40 were boys and 21 were girls (median age, 7 years; range, 3-13 years), treated between October 1996 and October 2003. Sagittal T(1)-weighted magnetic resonance images were used for the craniocaudal measurements. The measurements numbered 275 (median, 5/patient; range, 3-7). The median follow-up after CSI was 44.1 months (range, 13.8-74.9 months). RESULTS: Significant growth was observed in all measured vertebrae. Excluding C3-C4, the growth rate of the grouped vertebrae was affected by age, gender, and CSI dose (risk classification). The risk classification alone affected the growth rates of C3 (p = 0.002) and L3 (p = 0.02). Before CSI, the length of all vertebral bodies was an increasing function of age (p <0.0001). The C3 length before CSI was affected by gender and risk classification: C3 was longer for female (p = 0.07) and high-risk (p = 0.07) patients. CONCLUSION: All vertebrae grew significantly after CSI, with the vertebrae of the boys and younger patients growing at a rate greater than that of their counterparts. The effect of age was similar across all vertebrae, and gender had the greatest effect on the growth of the lower cervical and upper thoracic vertebrae. The effect of the risk classification was greatest in the lumbar spine by a factor of < or = 10.

Near fatal haemorrhage 35 years after radiation for laryngeal cancer: emergency embolisation of a vertebral artery aneurysm.

The authors report a rare case of a 75 year old man who presented 35 years after radiotherapy for carcinoma of the larynx, with catastrophic bleeding through the mouth. Both the time and mode of presentation were unusual. The patient required emergency sacrifice of the left vertebral artery to stop the bleeding. The literature has been reviewed.

A split-parotid delineation approach for dose optimization in volumetric modulated arc therapy for nasopharyngeal carcinoma patients with parapharyngeal space invasion and level IIa cervical lymph node involvements.

OBJECTIVE: This study evaluated the potential benefit of a split-parotid delineation approach on the parotid gland in the treatment planning of patients with nasopharyngeal carcinoma (NPC). METHODS: 50 patients with NPC with parapharyngeal space (PPS) and/or level IIa cervical node involvements were divided into three groups: PPS only, level IIa cervical node only and both. Two volumetric-modulated arc therapy plans were computed. The first plan (control) was generated based on the routine treatment-planning protocol, while the second plan (test) was computed with the split-parotid delineation approach, in which a line through the anterolateral margin of the retromandibular vein was created that divided the parotid gland into anterolateral and posteromedial subsegments. For the test plan, the anterolateral subsegment was prescribed, with a dose constraint of 25 Gy in the plan optimization. Dosimetric data of the parotid gland, target volumes and selected organs at risk (OARs) were compared between the control and test plans. RESULTS: The mean dose to the anterolateral subsegment of the parotid gland in all three groups was kept below 25 Gy. The test plan demonstrated significantly lower mean parotid dose than the control plan in the entire gland and the anterolateral subsegment in all three groups. The difference was the greatest in Group 3. CONCLUSION: The split-parotid delineation approach significantly lowered the mean dose to the anterolateral subsegment and overall gland without greatly compromising the doses to target volumes and other OARs. The effect was more obvious for both PPS and level IIa cervical node involvements than for either of them alone. ADVANCES IN KNOWLEDGE: It is the first article based on the assumption that parotid gland stem cells are situated at the anterolateral segment of the gland, and applied the split-parotid delineation approach to the parotid gland in the treatment planning of patients with NPC with PPS and level IIa cervical node involvements, so that the function of the post-radiotherapy parotid gland might be better preserved.

Setup uncertainties for inter-fractional head and neck cancer in radiotherapy.

PURPOSE: The aim of this study is to determine the inter-fractional motion of cervical spine in radiotherapy (RT). MATERIALS AND METHODS: Eleven localized head and neck cancer patients who were treated from April 2014 to September 2015 were evaluated. Every patient underwent 3 times of computed tomography (CT) simulation with equivalent setting. Left-right (LR, x) and antero-posterior (AP, z) directional shift of cervical spine were evaluated using 33 number of CT image. In regard to random error, geometric changes were evaluated by 22 data set (compared the first obtained CT to second or third CT) by one-sample T test. Systemic error was evaluated by each patients' data set (11 pairs) by paired T test. RESULTS: The mean random error of LR and AP translational shift of cervical spine were -0.39 ± 3.24 mm and -0.57 ± 0.99 mm respectively. The mean random error of translational change of AP direction showed statistical significance (p = 0.014). The mean random error of x and z rotational shift were -0.07 ± 0.29° and -0.05 ± 0.35°, respectively. The mean systemic error of translational shift of LR and AP direction were -0.64 ± 2.57 mm and -0.33 ± 1.22 mm, respectively. The mean systemic error of rotational shift of x and z were 0.01 ± 0.18° and -0.27 ± 0.33°, respectively. The mean systemic error of rotational changes of z direction showed statistical difference (p = 0.022). CONCLUSIONS: We have to be aware of the inter-fractional motion of cervical spine in head and neck RT and give enough margins in RT planning.

Short-term changes in prostacyclin secretory profile of irradiated rat cervical spinal cord.

Prostaglandins changes in radiation myelopathy (RM) have been previously reported. In the present study, we decided to determine the profile of Prostacyclin (PGI2) content in irradiated rat cervical cord. Wistar rats were irradiated with doses of 2,4,6,15,25 and 30 Gy of X-rays. After 24 h, 2 and 13 weeks post-irradiation, samples of spinal cord were prepared for evaluation of PGI2 and histopathologic changes. Prostacyclin content was determined by quantification of 6-keto-prostaglandin-F1alpha (prostacyclin major metabolite). Irradiated segments of spinal cord were stained routinely for histological studies. Results of irradiated were compared to control groups. Average ratio values of 6-keto-PG-F1alpha for doses of 2-30 Gy were between 67.5% and 107%, 65.41% and 100.54%, and 62.20% and 98.89% for 24 h, 2 and 13 weeks post-irradiation, respectively. Histopathological studies showed marked gliosis and vascularities in irradiated specimens. PGI2 bimodal secretory profile was observed along with histopathological changes in this study. Our results can further emphasize on the role of PGI2 in RM.