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@#Interventional radiotherapy, also known as brachytherapy, is the use of sealed radioactive sources that directly deliver radiation to the tumor or tumor bed. Its unique dose distribution profile allows for high conformality, making it a very useful modality in the treatment of cancers in the head and neck, where different organs and substructures that serve various but related functions are situated close to each other. In recent years, we have seen several important technological breakthroughs in the field, especially regarding its application in head and neck cancers. These include advances in treatment delivery, dosimetry planning , image guidance , and catheter positioning techniques . These innovations, which often require interdisciplinary interventions, have resulted in enhanced treatment accuracy, and therefore, major clinical advantages in terms of increased local control and decreased toxicity, as well as economic benefits. In order to highlight the differences from old brachytherapy techniques, a more appropriate terminology should perhaps be adopted, to signify these advancements that resulted in new opportunities, approaches and better outcomes – interventional radiotherapy (IRT). Such a change in terminology will not only allow recognition of these advances, but also a meaningful distinction from obsolete techniques and suboptimal outcomes that are associated with traditional brachytherapy. This is very important in increasing awareness among professionals outside the field of radiation oncology. We briefly review these recent advances, the current indications, and future directions for IRT in head-and-neck cancers.
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BrachytherapyABSTRACT
External beam radiation therapy (EBRT) is one of the main treatments for prostate cancer, and image-guided implementation of EBRT is more suitable for accurate radiotherapy. As a new type of image-guided technology, the Clarity system has been applied in the real-time tracking during EBRT for prostate cancer in clinical practice. While improving the accuracy of EBRT targeting, it also significantly reduces the side effects of traditional EBRT. In this article, the application of Clarity system in EBRT of prostate cancer and its existing problems were systematically elucidated.
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Brachytherapy is an integral part of radiotherapy treatment for cervical cancer. With the rapid development of medical imaging technology, three-dimensional (3D) imaging modality has been applied in the brachytherapy for cervical cancer. After computed tomography (CT) and magnetic resonance imaging (MRI), 3D ultrasound has been gradually applied to guide the brachytherapy for cervical cancer due to its superior soft tissue imaging characteristics, economy, high efficiency and convenience. In this article, the research progress on the application of ultrasonography in brachytherapy was summarized according to literature review, aiming to provide reference for subsequent research.
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Brachytherapy is an integral part of radiotherapy treatment for cervical cancer.With the rapid development of medical imaging technology,three-dimensional (3D) imaging modality has been applied in the brachytherapy for cervical cancer.After computed tomography (CT) and magnetic resonance imaging (MRI),3D ultrasound has been gradually applied to guide the brachytherapy for cervical cancer due to its superior soft tissue imaging characteristics,economy,high efficiency and convenience.In this article,the research progress on the application of ultrasonography in brachytherapy was summarized according to literature review,aiming to provide reference for subsequent research.
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Objective To retrospectively analyze the setup error in radiotherapy of somal tumors and body metastases using the ExacTrac X-ray portal image,and to evaluate the feasibility and effectiveness of 6D setup error correction in body radiotherapy.Methods The translational and rotational setup errors were calculated by registering the bony structures on the ExacTrac X-setup images to that of the digitally reconstructed setup images,and the corresponding residual errors were calculated together.Results The translational and rotational setup errors in the x (left-right),y (superior-inferior),z (anterior-posterior) and Rx (sagittal),Ry (transverse),Rz (coronal) directions were(2.27±2.02) mm,(4.49±2.52) mm,(2.27± 1.37) mm and (1.02 ± 0.73) °,(0.67 ± 0.68) °,(0.76 ± 0.84) °,respectively.The residual translational and rotational setup errors in the x(r),y(r),z(r) and Rx(r),Ry(r),Rz(r) directions were(0.27±0.48)mm,(0.37±0.45)mm,(0.22±0.30)mm and (0.17±0.33)°,(0.14±0.34)°,(0.16± 0.28) ° respectively.Conclusions Besides the translational setup errors,a certain amount of rotational setup errors exist in radiotherapy of somal tumors and body metastases.By using the 6D setup error correction of the ExacTrac system,a translational less than 0.4 mm and rotational setup errors less than 0.2° could be achieved.
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Anatomy and surgery teaching has always been a difficulty in clinical medical education. In particular, the anatomy and surgery teaching under the endoscope is more difficult to learn and under-stand because of the visual differences with the direct vision. If the students misunderstand, it may lead to the severe surgical complications. We applied the image-guidance technology in the teaching of rhinology endoscope surgery, which can help teachers to teach the sinonasal anatomical structure and give an accurate explanation of surgical procedures. According to the questionnaire survey, 96.23% (51/53) of the students thought the method was effective and clear, and 98.11% (52/53) of them thought the method was better than the traditional teaching method of nasal endoscope. By this technology, the students can acquire a deeper understanding of the anatomy and surgery procedure. It especially fits the surgery teaching of the sinonasal occupying lesion.
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Objective To investigate the effect of the correction of the position error of the abdominal tumor by cone beam scanning. Methods Six patients with abdominal tumor were selected with double-blind method, and electronical portal imaing device was used to collect the information of the patient dosimetry during radiotherapy.EDOSE tool was applied to 3D dose reconstruction so as to execute real-time 3D dose verification of the treatment plan. Each patient had 5 sets of data acquired when image guidance existed and another 5 sets when image guidance was absent. The treatment effects with or without image guidance were compared.Results The overall γ passing rate with cone beam CT image guidance gained no advantages over that without image guidance, though the setup error was corrected to some extent. Image guidance contributed nothing to increasing target area coverage while decreasing exposure dose to normal tissue. Conclusion Setup error correction by the image guidance based on bone marker has no significant effect on improving 3D dose verification and dose accuracy during the radiotherapy of the abdominal tumor patient.
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Objective To measure the irradiation doses from the image beam line (IBL) of Artiste linac under the 2Dplanar,MV CBCT,6 MV 2Dplanar and Somatom CT modes to select an appropriate image-guided mode combined with the irradiation sites. Methods The head, chest and pelvic phantom doses from the IBL under the 2Dplanar,MV CBCT and 6 MV 2Dplanar modes were measured by using IBA Dose 1 electrometer and FC65 ionization chamber.The irradiation doses of Somatom CT scans of the head, chest and pelvis were measured using IBA Dosimax plus A system and the measurement results were analyzed. Results In the head and neck, the average irradiation dose was 16. 60 mGy under IBL 2Dplanar mode, 58. 73 mGy under IBL MV CBCT mode, 19. 83 mGy under 6 MV 2Dplanar mode and 7-9 mGy under Somatom CT. In the chest, the average irradiation dose was 14. 08 mGy under IBL 2Dplanar mode, 49. 17 mGy under MV CBCT mode, 18. 97 mGy under 6 MV 2Dplanar mode and 9-11 mGy under Somatom CT mode.In the pelvis, the average irradiation dose was 13. 36 mGy under IBL 2Dplanar mode, 45. 65 mGy under MV CBCT mode, 17. 52 mGy under 6 MV 2Dplanar mode and 12-15 mGy under Somatom CT mode. Conclusions In the head and neck, the image quality under IBL 2Dplanar mode is recommended, which is qualified for image registration standards. Somatom CT mode is suitable for the chest. In the pelvic region, IBL 2DPlanar mode can be applied when the intestinal cavity and bladder are well filled, and MV CBCT mode can be chosen if they are poorly filled.
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To review retrospectively six cases of rhino-orbital related endoscopic surgeries aided by Fusion electromagnetic system,to explore the indications and clinical value of image guided technique in endonasal endoscopic surgery.Retrospective research methods were used.In this study,six cases of nasal endoscopic sinus surgery using Fusion electromagnetic system were analyzed,including 1 nasal penetrating foreign body,2 optic nerve decompressions,1 orbital apex hemangioma,1 sieve frontal sinus cyst,1 intraorbital mass biopsy.The preparation time of navigation system,the accuracy of intraoperative positioning and surgical coherence,intraoperative and postoperative complications of surgery were recorded.The average preparation time was(8.13 ± 1.858)min.In the navigation,the sinus ostium,orbital cardboard,skull base,optic nerve,internal carotid artery and other important structures can be accurately located in all patients,while registrations had been accurate within 1 mm.Six patients were successfully operated by image guided technique.There was no intracranial or intraorbital complications due to intraoperation error.Image guided technique allows for a truely microinvasive and accurate rhino-orbital related endoscopic surgeries.It requires less preoperative preparation time,has high surgical navigation accuracy,improves the surgical coherence and safety,and reduces the surgical complicationgs.However,as an auxiliary tool,it can not replace the surgeon's anatomical knowledge,surgical training and clinical experience.
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Humans , Endoscopy , Methods , Nasal Cavity , General Surgery , Orbit , General Surgery , Retrospective Studies , Skull Base , General Surgery , Surgery, Computer-AssistedABSTRACT
Objective To study the setup accuracy and other factors during frameless stereotactic radiosurgery (SRS) of intracraial tumor using ExacTrac X-ray image guide system.Methods Totally 119 intracranial tumor patients from August 2014 to February 2016 underwent auto setup with infrared marker.Bilateral oblique cross field images were obtained with ExacTrac X-ray system,and went through comparison,registration and correction with the digitally reconstructed ones of the planning system.Then the translation accuracy errors at LAT,LNG and VRT directions and corresponding rotational accuracy errors were acquired,and the errors experienced extended analysis.Results The translation errors at LAT,LNG and VRT directions acquired with ExacTrac X-ray image guidance system and 6DOF couch were (0.16±0.13) mm,(0.17±0.14) mm and (0.15±0.11) mm respectively,the corresponding rotational errors were (0.21±0.15),(0.18±0.15),(0.18±0.14)° respectively,and the vector error was (0.32±0.16) mm.All of 3 translation and 3 rotational errors were in the SRS error range.Conclusion ExacTrac X-ray image guidance system combined with 6 degrees-of-freedom couch increases the treatment accuracy during frameless SRS,and thus is worthy promoting practically.
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Image-navigation-assisted positioning and puncturing system is a newly-developed treatment technology in recent years,which carries broad application prospects.It combines image and navigation technology together.Guided by the dynamic real-time imaging the operator can precisely manipulate the surgical instruments to operate on the target lesion,in this way the minimally-invasive interventional therapy can be greatly optimized.The image-guided methods mainly include ultrasound,CT,MR,etc.Based on the principles of different positioning methods,the navigation and positioning technology can be classified into mechanical positioning,optical positioning and electromagnetic positioning.Each image guidance and navigation technology has its own advantages and disadvantages.At present,image-navigation-assisted positioning and puncturing system has already been widely used in various minimally-invasive interventional therapies,such as tumor biopsy,local ablation therapy,radioactive seed implantation,etc.,and satisfactory clinical results have been achieved although in clinical practice they still have some shortcomings.In this paper,the application of this technique in minimally-invasive interventional therapy is briefly reviewed.
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AIM: To explore the nursing cooperation highlights of eight osteopetrosis patients underwent optic nerve decompression via transsphenoidal microsurgical approach instead of routine pathway, and to improve the quality of nursing cooperation. ·METHODS: We enrolled 8 cases ( left eye in 3 cases, right eye in 5 cases ) of osteopetrosis patients referred from the Eye Hospital of Wenzhou Medical University during February 2012 to November 2016. Patients received ophthalmic examinations including visual acuity and diagnostic imaging tests in pre-operation and post -operation. All eyes were performed surgical optic nerve decompression through endoscopic approach in assist of image guidance system. We retrospectively analyzed the clinical data and surgical cooperation procedure of these cases and summarized nursing cooperation experience. ·RESULTS:The operations of 8 patients were completed successfully without massive hemorrhage. Mean visual acuity improved from pre-operation (2. 5±2. 1) to post-operation (3. 4±1. 9). Cerebrospinal fluid leakage occurred in 1 patient and was instantly repaired during the operation. We performed the nursing strategy as postural drainage, condition monitoring and conscious assessment intra-and post-operation. ·CONCLUSION: It is the critical for this kind of surgery that both circulating nurse's high-skilled cooperation to the connection and operation of the navigation system, to treat with complication during the surgery, and scrub nurse's sufficient preparation of surgical instruments and consumables, proficient equipment delivery, meticulous management, use and maintenance of equipment.
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Objective:The purpose of this paper is to introduce a method of using compensate angles to eliminate rotation set-up errors without six-degree of freedom couch. Methods: To detect six-degree of freedom set-up errors, cone-beam computed tomography (CBCT) scans were acquired. These set-up errors were defined as a matrix to transform from accelerator coordinate system to patient coordinate system. Two independent vectors were defined to describe angles of gantry, collimator and couch in accelerator machine. Transformation of vectors were determined by transformation matrix and re-calculated back to the machine angles. Results:It was found that compensate angles can fully corrected the rotation angles in set-up with limited time consuming. It is feasible to implement compensate angles in routinely radiation procedure. Conclusion:With this method, it is possible to implement the complete corrections of set-up errors in radiotherapy without six-degree of freedom couch and it is convenient in operation as well.
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Objective To compare the setup errors between single-site and two-site image guidance in treating multiple metastases using Tomotherapy.Methods A total of 1 220 sets of megavoltage CT (MVCT) images from 50 multiple metastases patients were collected.The setup errors of two anatomic sites were determined by registration of MVCT images with planning images.Bland-Altman plot analysis was used to assess the coincidence of these two methods.Pearson correlation analysis was performed to evaluate the correlation of the setup errors determined by two sets of data and to analyze the deviation values of setup errors.Results The deviation values of setup errors more than 3 mm between two sites were 34％,46％ and 28％ in lateral (x),longitudinal (y),vertical (z) directions,respectively.The deviation values of setup errors more than 5 mm were 10％,16％ and 8％,respectively.The BlandAltman plot analysis showed that the 95％ agreement limits of agreement were (9.3,-10.6),(10.5,-11.7),(7.3,-6.9) mm in x,y,z directions,respectively,which were all out of 5 mm tolerance.The Pearson coefficient of correlation along all three directions was less than 0.05,and R2 was 0.074,0.475,and 0.178 in x,y,z directions,respectively.Conclusions To determine the setup errors for patients with multiple metastases,single-site image guidance method is not consistent,and the two site image guidance method would be recommended.
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Objective To explore the relationship of X-ray exposure parameters and false-node rate during image-guidance treatment with CyberKnife spine tracking.Methods Using spine tracking planning on a chest phantom,several combinations of X-ray exposure parameters were used to locate.The false-node ratio and the surface absorbed dose were investigated and the radiation dose was optimized.Results The false-node ratio and surface absorbed radiation dose decreased when the X-ray exposure parameters increased until they saturated.In the range of ≤5.0％ false-node rate,the surface absorbed radiation dose was 0.11,0.26 mGy,and 0.31-0.46 mGy,when the false-node rate was 2.77％,1.07％and 1.0％,respectively.Conclusions In image-guided treatment of CyberKnife,the radiation dose would be optimized,and the patient's radiation dose would be reduced greatly,which is important to protect the patients.
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Objective To compare the clinical target volume (CTV) expanding margins in the mid-and upper-thoracic esophageal carcinoma during radiotherapy measured with and without online image guidance technique by CT on rail.Methods 100 patients with mid-and upper-thoracic esophageal carcinoma undergoing intensity modulated radiotherapy received CT scanning.Image registration was conducted between the scanning results and the planned CT images,thus set-up error data were acquired and got on-line correction.Fifty patients were randomly selected to undergo additional post-treatment CT scanningso as to analyze the revised residuals,displacement during treatment,and infra-fraction GTV shifts.Results Compared to the radiotherapy without CT-based image guidance,the CTV expanding margins obtained with CT-based image guidance was reduced significantly from 9.1,8.8 and 6.1 mm to 4.1,4.5 and 4.3 mm in the left-right,head-feet,and belly-back directions respectively.Conclusions The on-line image-guided technology significantly improves the accuracy of target and reduces the CTV expanding margins.
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AIM:To evaluate the availability and our experience of intraoperative image-guidance in endoscopic nasocular operation.METHODS:Seven cases of endoscopic nasal surgery with intraoperative image-guidance were retropectively reviewed,including 3 cases of optic nerve injury;3 cases of foreign object of optic behind the eyeball;1 case of retrobulbar tumor(angeioma).RESULTS:The preoperative preparatory time would take 15 minutes,including coordination,head holder localization,conventional instrument registration.In our cases,the localization accuracy between 3-D image landmarks of navigation system and actual anatomical landmarks was less than 1.3mm.The optic nerve and other anatomical points could be orientated accurately in intraoperative procedures.No complication occurred.CONCLUSION:Nasal endoscope combined with imageguidance systems provides accurate anatomical localization of anterior skull base with enlarged operation field.It is possible for surgeons to observe important anatomical structures during endoscopic surgery.It could increase the effectiveness and decrease surgical complications,especially in complicated cases.