Comparison between 4D robust optimization methods for carbon-ion treatment planning

Intensity-modulated particle therapy(IMPT)with carbon ions is comparatively susceptible to various uncertainties caused by breathing motion,including range,setup,and target positioning uncertainties.To determine relative biological effectiveness-weighted dose(RWD)distributions that are resilient to these uncertainties,the reference phase-based four-dimensional(4D)robust optimization(RP-4DRO)and each phase-based 4D robust optimization(EP-4DRO)method in carbon-ion IMPT treatment planning were evaluated and compared.Based on RWD distributions,4DRO methods were compared with 4D conventional optimization using planning target volume(PTV)margins(PTV-based optimization)to assess the effectiveness of the robust optimization methods.Carbon-ion IMPT treatment planning was conducted in a cohort of five lung cancer patients.The results indicated that the EP-4DRO method provided better robustness(P=0.080)and improved plan quality(P=0.225)for the clinical target volume(CTV)in the individual respiratory phase when compared with the PTV-based optimization.Compared with the PTV-based optimization,the RP-4DRO method ensured the robustness(P=0.022)of the dose distributions in the reference breathing phase,albeit with a slight sacrifice of the target coverage(P=0.450).Both 4DRO methods successfully maintained the doses delivered to the organs at risk(OARs)below tolerable levels,which were lower than the doses in the PTV-based optimization(P<0.05).Furthermore,the RP-4DRO method exhibited significantly superior performance when compared with the EP-4DRO method in enhancing overall OAR sparing in either the individual respiratory phase or reference respiratory phase(P<0.05).In general,both 4DRO methods outperformed the PTV-based optimization in terms of OAR sparing and robustness.

Research Progress on Individualized Treatment of Splenic Aneurysm

Splenic artery aneurysm has a hidden onset and atypical symptoms.There are various diagnostic methods for splenic aneurysms,among which ultrasound is the first choice for aneurysm screening.The diagnostic rate of CTA and DSA reaches 100%.In clinical practice,it is necessary to integrate medical history,symptoms and signs,and multiple imaging results to improve the diagnostic rate.In terms of treatment plans,both intervention and surgical procedures have their strengths,and the application of intervention will be more extensive.We need to adhere to the principle of individualization and choose a reasonable treatment plan for patients.At present,there are many reports on pregnant women with large splenic aneurysms both domestically and internationally.Some scholars believe that large splenic aneurysms may be related to hormonal imbalances during pregnancy,and the specific pathogenic mechanism will become a hot topic in future research.

Comparative Study between Field-in-Field and IMRT Techniques in Prostate Cancer Radiotherapy: A Treatment Planning Study

Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, to expose the targeted tumor to the full radiation dose and to spare the nearby normal tissues (or organs) from being exposed to high amounts of radiation more than its tolerance dose limits. FIF is a forward planning while IMRT is an inverse planning and FIF is a forward IMRT. Aim: The purpose of this study was to compare between Field-in-Field and IMRT techniques in prostate cancer radiotherapy. Method: A treatment planning system supporting both inverse and forward planning facilities is used. Ten prostate cancer patients were planned with both FIF and IMRT planning techniques. Doses received by the Planning Target Volume (PTV) and Organs at Risk (OARs) were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that the IMRT planning technique achieved better dose coverage to the PTV than the FIF planning technique but, except RT and LT Femoral Heads, FIF achieved a better protection to the Rectum and the Bladder (OARs) than IMRT. Conclusions: The results showed that the inverse planning based IMRT technique is better and recommended in the prostate cancer radiotherapy than the FIF technique.

Volumetric-modulated arc therapy vs c-IMRT in esophageal cancer:A treatment planning comparison

AIM： To compare the volumetric-modulated arc ther- apy （VMAT） plans with conventional sliding window intensity-modulated radiotherapy （c-IMRT） plans in esophageal cancer （EC）. METHODS： Twenty patients with EC were selected, including 5 cases located in the cervical, the upper, the middle and the lower thorax, respectively. Five plans were generated with the eclipse planning sys- tem： three using c-IMRT with 5 fields （5F）, 7 fields （7F） and 9 fields （gF）, and two using VMAT with a single arc （1A） and double arcs （2A）. The treatment plans were designed to deliver a dose of 60 Gy to the plan-ning target volume （PTV） with the same constrains in a 2.0 Gy daily fraction, 5 d a week. Plans were normal- ized to 95% of the PTV that received 100% of the pre- scribed dose. We examined the dose-volume histogram parameters of PTV and the organs at risk （OAR） such as lungs, spinal cord and heart. Monitor units （MU） and normal tissue complication probability （NTCP） of OAR were also reported. RESULTS： Both c-IMRT and VMAT plans resulted in abundant dose coverage of PTV for EC of different Io- cations. The dose conformity to PTV was improved as the number of field in c-IMRT or rotating arc in VMAT was increased. The doses to PTV and OAR in VMAT plans were not statistically different in comparison with c-IMRT plans, with the following exceptions： in cervical and upper thoracic EC, the conformity index （CI） was higher in VMAT （1A 0.78 and 2A 0.8） than in c-IMRT （5F 0.62, 7F 0.66 and 9F 0.73） and homogeneity was slightly better in c-IMRT （7F 1.09 and 9F 1.07） than in VMAT （1A 1,1 and 2A 1.09）, Lung V30 was lower in VMAT （1A 12.52 and 2A 12.29） than in c-IMRT （7F 14.35 and 9F 14.81）. The humeral head doses were significantly increased in VMAT as against c-IMRT. In the middle and lower thoracic EC, CI in VMAT （1A 0.76 and 2A 0.74） was higher than in c-IMRT （5F 0.63 Gy and 7F 0.67 Gy）, and homogeneity was almost similar between VMAT and c-IMRT. V20 （2A 21.49 Gy vs 7F 24.59 Gy and 9F 24.16 Gy） and V30 （2A 9.73 Gy vs 5F 12.61 Gy, 7F 11.5 Gy and 9F 11.37 Gy） of lungs in VMAT were lower than in c-IMRT, but low doses to lungs （V5 and Vl0） were increased. V30 （1A 48.12 Gy vs 5F 59.2 Gy, 7F 58.59 Gy and 9F 57.2 Gy）, V40 and V50 of heart in VMAT was lower than in c-IMRT. MUs in VMAT plans were significantly reduced in comparison with c-IMRT, maximum doses to the spinal cord and mean doses of lungs were similar between the two techniques. NTCP of spinal cord was 0 for all cases. NTCP of lungs and heart in VMAT were lower than in c-IMRT. The advantage of VMAT plan was enhanced by doubling the arc. CONCLUSION： Compared with c-IMRT, VMAT, especial- ly the 2A, slightly improves the OAR dose sparing, such as lungs and heart, and reduces NTCP and MU with a better PTV coverage.

CT image fusion in the evaluation of radiation treatment planning for non-small cell lung cancer

Objective: We studied the application of CT image fusion in the evaluation of radiation treatment planning for non-small cell lung cancer (NSCLC). Methods: Eleven patients with NSCLC, who were treated with three-dimensional con-formal radiation therapy, were studied. Each patient underwent twice sequential planning CT scan, i.e., at pre-treatment, and at mid-treatment for field reduction planning. Three treatment plans were established in each patient: treatment plan A was based on the pre-treatment planning CT scans for the first course of treatment, plan B on the mid-treatment planning CT scans for the second course of treatment, and treatment plan F on the fused images for the whole treatment. The irradiation doses received by organs at risk in the whole treatment with treatment A and B plans were estimated by the plus of the parameters in treatment plan A and B, assuming that the parameters involve the different tissues (i.e. V20=AV20+BV20), or the same tissues within an organ (i.e. Dmax=ADmax+BDmax). The assessment parameters in the treatment plan F were calculated on the basis of the DVH of the whole treatment. Then the above assessment results were compared. Results: There were marked differ-ences between the assessment results derived from the plus of assessment parameters in treatment plan A and B, and the ones derived from treatment plan F. Conclusion: When a treatment plan is altered during the course of radiation treatment, image fusion technique should be performed in the establishment of a new one. The estimation of the assessment parameters for the whole treatment with treatment plan A and B by simple plus, is inaccurate.

Tridimensional Treatment Planning and Rapid Prototyping for Maxillofacial Prosthesis

The current simulation planning systems for maxillofacial prosthesis surgery were used to extrapolate 3D surgical movements and outcomes based on the 2D radiographs, which were inadequate for complex surgical movements.A 3D treatment planning system based on the computerized tomography (CT) data was presented. A 3D data field was constructed out of the sectional image stack through linear interpolation. After objective tissue segmentation and using the marching cubes algorithm method, the triangular mesh model and 3D geometric model of diseased facial skeleton were reconstructed. Then the model was cut, the segments were moved or rotated to their predicted positions, and angles and distances were measured. After triangular mesh model was decimated, a RP model was manufactured for surgical simulation and prosthesis design. The system was used in clinic with more than fifty cases and technically validated with success.

Complex Target Volume Delineation and Treatment Planning in Radiotherapy for Malignant Pleural Mesothelioma (MPM)

Introduction: Radiotherapy alone or combined with surgery and/or chemotherapy is being investigated in the treatment of malignant pleural mesothelioma (MPM). This study aimed to simulate a Volumetric Modulated Arc Therapy (VMAT) treatment of a patient with MPM. Materials and Methods: CT images from a patient with intact lungs were imported via DICOM into the Pinnacle3 treatment planning (TP) system (TPS) and used as a model for MPM to delineate organs at risk (OAR) and both clinical and planning target volumes (CTV and PTV) with a margin of 5 mm. Elekta Synergy with 6 MV photons and 80 leafs MLCi2 was employed. VMAT plans were generated using two coplanar arcs with gantry rotation angles of 178° - 182°, the collimator angles of each arc were set to 90°, Octavius® 4D 729 was employed for quality assurance while the calculated and measured doses were compared using VeriSoft. Results: A TP was achieved. The Gamma volume analysis with criteria of 3 mm distance to agreement and 3% dose difference yielded the gamma passing rate = 99.9%. The reference isodose was 42.75 Gy with the coverage constraints for the PTV D95 and V95 = 95.0% of 45 Gy. The remaining dosimetric parameters met the recommendations from the clinically acceptable guidelines for the radiotherapy of MPM. Conclusion: Using well-defined TV and VMAT, a consistent TP compared to similar ones from publications was achieved. We obtained a high agreement between the 3D dose reconstructed and the dose calculated.

Comparison of the dose to lung volume between supine and prone position during treatment planning

Objective The aim of the study was to compare the dose to lung volume in the supine and prone posi- tion while designing CyberKnife treatment plans to treat metastatic tumors in the spinous processes of the thoracic vertebrae, and offer a reference for reducing damage to normal tissues. Methods Nine cases of metastatic tumors in the spinous processes of the thoracic vertebrae were selected, and then we designed treatment plans based on the supine and prone positions and compared the results. Results In contrast with the treatment plan based on the prone position, the one for the supine position required 14862-36337 MU more; the lung D5% was 5.20-7.90 Gy higher; and the lung D20% was 2.61-5.73 Gy higher. The difference of dose to spine volume between the two plans was -2.21-2.67 Gy; to the skin volume was -3.93-7.85 Gy; and to the esophagus was 0.28-6.39 Gy. Conclusion The treatment plan based on the prone position of patients can better protect lung tissues than the one based on the supine position, and can also improve the avaUabilitv of beams.

Advanced Treatment Planning in Cancer Thermal Therapies

CEM43 thermal dose is a very common concept in thermal oncology.Thermal dose is the maximum amount of energy that can be transmitted during hyperthermia therapy conducted on temperature-sensitive tissue.Thermal dose is also the maximum value of local energy accumulation in human bodies,which can lead to tissue injury and pain.Thermal dose can also decrease the finishing temperature and reduce the energy to the tolerable range.There are two functions of the individualized hyperthermia treatment plan:it determines the setting and location that can realize the best tumor hyperthermia therapy;at the same time,it can decrease the effect of hyperthermia therapy on healthy tissues.There are four steps in the treatment plan of hyperthermia therapy for tumors:the first step is to establish a three dimensional human body model and its corresponding an atomical structure that can be used in numerical algorithm via medical imaging resources;the second step is to determine the volume of the electromagnetic energy accumulation.Based on the peculiarity of frequency and materials,even full-wave electromagnetic wave or quasi-static technique can be used to determine the tissue distribution.Evaluation of the therapy can be conducted based on thermal dose and the corresponding tissue damage model;the third step is to use Arrhenius model to provide direct evaluation of tissues in the thermal ablation zone,solidification zone,as well as the necrotic area;the last step is the optimization of the treatment plan.

Prevention and Treatment of Gastrointestinal Diseases in College Students

Objective:This paper aims to discuss the prevention and treatment strategies of gastrointestinal diseases in college students.Methods:A sample of 60 college students suffering from gastrointestinal diseases,from August 2021 to August 2022,was used to discuss the symptoms,causes,prevention strategies,and treatment strategies of gastrointestinal diseases based on questionnaire survey.Results:The high-incidence types of gastrointestinal diseases in college students mainly included chronic gastritis,acute gastritis,duodenal ulcer,and dyspepsia,which were closely related to mental state,diet,and living habits.Conclusion:There are many causes of gastrointestinal diseases in college students.During the period of active symptomatic treatment,it is necessary to focus on the prevention of gastrointestinal diseases in colleges and universities,correct the unhealthy lifestyle of students,and reduce the risk of gastrointestinal diseases.

Optimal scheme of Shengmai Injection in the treatment of angina pectoris of coronary heart disease based on Louvain algorithm: A real world study

Objective:To explore the optimal scheme of Shengmai Injection combined with other drugs for clinical doctors.Methods:Based on the large-scale data warehouse established by the institute of Clinical Basic Medicine,Chinese Academy of Traditional Chinese Medicine,the hospital information system of 22 large-scale tertiary hospitals in China was collected and 1751 patients with angina pectoris who were treated with Shengmai Injection were selected.Louvain algorithm and complex network analysis are used to build the model to summarize the rule of Shengmai Injection in the treatment of angina pectoris of coronary heart disease.Results:On the basis of Shengmai Injection,according to the symptom treatment of angina pectoris of coronary heart disease,nitrates or Suxiao Jiuxin Pill was used to dilate coronary artery;for the treatment of risk factors of angina pectoris,a combination of"insulin+acarbose+bisoprolol+nifedipine+captopril+estazolam"was used to control blood glucose and blood pressure;"Ganmao Qingre Granule+levofloxacin"to treat upper respiratory tract infection and other medication regimens were used as well.For the complications of angina pectoris of coronary heart disease,"furosemide+spironolactone+potassium chloride+magnesium sulfate"was used to reduce edema and“isosorbide nitrate+metoprolol+Shenmai injection+Wenxin Granule"was used to improve symptom of heart failure of qi and yin deficiency type.Conclusion:The therapeutic regimen of Shengmai Injection combined with traditional chinese medicine and western medicine is basically consistent with the current guidelines,but more clinical studies are still needed to explore more effective combination therapy.

Diagnosis and treatment discussion of congenital factor VII deficiency in pregnancy:A case report

BACKGROUND Congenital factor VII deficiency(FVIID)is a rare autosomal recessive genetic disorder.The clinical manifestations of this deficiency vary greatly.Predicting the risk of bleeding during and after childbirth of pregnant women with congenital FVIID is difficult.Recombinant factor VIIa is the most common replacement therapy for FVIID.However,no unified diagnosis and treatment plan for pregnant women with congenital FVIID has been established.CASE SUMMARY We report the clinical history of a pregnant woman who was considered to have congenital FVIID.Recombinant factor VIIa was prophylactically administered to the pregnant woman at the time of cervical fully opening.She successfully delivered a live infant without any complications,such as postpartum hemorrhage,neonatal abnormalities,and so on.CONCLUSION Prophylaxis of recombinant factor VIIa during delivery can effectively reduce the incidence of postpartum hemorrhage among pregnant women with congenital FVIID associated with a high risk of bleeding.

Clear aligner treatment for a four-year-old patient with anterior crossbite and facial asymmetry:A case report

BACKGROUND Clear aligners have been widely used to treat malocclusions from crowding,extraction cases to orthodontic-orthognathic cases,and practitioners are exploring the border of it.For the first time,clear aligners were used to early intervene anterior cross-bite and facial asymmetry.CASE SUMMARY This case report described a four-year-old child presented with anterior cross-bite and facial asymmetry associated with functional mandibular shift,who had undergone a failed treatment with conventional appliances.The total treatment time was 18 weeks,and a stable outcome was obtained.CONCLUSION The increasing need in early treatment highlights the need for clinicians to thoroughly investigate for the patient regarding clinical manifestation as well as patient compliance.We hope that our case will be contemplated by clinicians when seeking for treatment alternatives.

Evolving role of salvage reirradiation: Is global harmonization required before treatment guidelines can be developed?

Up to 90% of patients initially treated with curativeintent radiotherapy(RT) will experience locoregional failure. Historically, reirradiation(Re RT) was offered purely with palliative intent, if considered at all, due to concerns surrounding toxicity, tolerance of normal tissues, and choice of appropriate dose schedule. With technological advancements in RT delivery, coupled with longer survival in many malignancies secondary to improvements in systemic therapy, a small subset of patients presenting with localized recurrence is increasingly being offered salvage Re RT. However, this is largely on an ad hoc basis, guided mainly by small retrospective, single-institution reports. The patient population retreated, RT modality, dose received, degree of attrition and follow-up are extremely variable. The opportunity presently exists to apply lessons learned from the harmonization of the research efforts within the bone metastases community to the salvage Re RT situation: the adoption of common endpoints, minimum features to be incorporated into clinical trial design, and methods of data analysis and reporting. The Re RT data available must be harmonized so that valid, clinically applicable conclusions can be drawn. Collaboration in the form of an international registry of prospectively collected outcomes of patients reirradiated for cure for a variety of tumour sites would further support the evolution of Radiation Oncology towards personalized medicine, and away from the current "one-dose-fits-all" approach.

Analysis of novel coronavirus pneumonia treatment with Chinese herbal compound

Objective: To analyze the prescription law of TCM compound in the treatment of new coronavirus pneumonia, and provides reference for the clinical treatment of new coronavirus pneumonia. Methods: Collected Collected 24 novel coronavirus pneumonia related diagnostic and therapeutic plans issued by the National Health Council and the Chinese medicine authority from January 26, 2020 to March 8th ,the filtered solution involved in the formula, establishing database of traditional Chinese medicine compound prescription for the treatment of new crown pneumonia, the frequency of using frequency analysis methods of analysis and clustering analysis and association rules analysis to sort out data mining analysis of traditional Chinese medicine compound. Results: In this study, a total of 159 TCM compounds were included in the treatment of new crown pneumonia from the country and 23 provinces, municipalities and autonomous regions, involving 189 TCM compounds. A total of 62 high-frequency traditional Chinese medicines (frequency ≥ 11) were obtained, mainly including licorice, almond, ephedra, gypsum, Poria cocos, Huoxiang, etc The drug types are mainly heat-clearing drugs, vacuous drugs, moisture-curing drugs, and surfactant drugs. The main effect of the medicine was warm, cold, lukewarm and flat, the main effect of the medicine was bitter and bitter, and the main effect of the medicine was the lung, stomach and spleen. Cluster analysis results according to the performance of traditional Chinese medicine treatment of new crown pneumonia high frequency drugs into 7 classes;Association rule analysis results in 29 common drug pairs. Conclusion: In the treatment of pneumonia caused by new coronavirus infection with traditional Chinese medicine, the following characteristics are presented: the number of times of supplementing qi and Yin is more than that of attacking evil and maintaining health;The method of dispersing and solving the attack of wet, beneficial, wet, permeable and wet medicine fully embodies a variety of ways to drive away evil;In terms of drugs, heat-clearing drugs, deficiency drugs, dampness drugs and surface drugs are the main ones, highlighting that the basic treatment method is to dissolve dampness and detoxify, and replenish qi and Yin. In summary, this study can provide reference for guiding clinical drug use and developing new drugs.

Glimpse into the future of prosthodontics:The synergy of artificial intelligence

Prosthodontics,deals in the restoration and replacement of missing and structurally compromised teeth,this field has been remarkably transformed in the last two decades.Through the integration of digital imaging and threedimensional printing,prosthodontics has evolved to provide more durable,precise,and patient-centric outcome.However,as we stand at the convergence of technology and healthcare,a new era is emerging,one that holds immense promise for the field and that is artificial intelligence(AI).In this paper,we explored the fascinating challenges and prospects associated with the future of prosthodontics in the era of AI.

Evaluation of 3D-CRT and VMAT Radiotherapy Plans for Left Breast Cancer with Regional Lymph Nodes Irradiation

Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (PTV), while reducing the dose to organs at risk (OARs) which are normal tissues whose sensitivity to irradiation could cause damage that can lead to modification of the treatment plan. In the last decade, radiation oncologist started to use the Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast, in order to achieve better dose distribution and target dose to the PTV and OAR. The aim of this study is to compare 2 external radiotherapy techniques (VMAT vs 3D) for patients with node-positive left breast cancer. Patients and Methods: We randomly selected 10 cases of postoperative radiotherapy for breast cancer in our hospital. The patients are all female, the average age was 45.4 years old, and the primary lesions are left breast. The ANOVA test was used to compare the mean difference between subgroups, and the p value Results: Dose volume histogram (DVH) was used to analyze each evaluation dose of clinical target volume (CTV) and organs at risk (OARs). Compared to 3DCRT plans, VMAT provided more uniform coverage to the breast and regional lymph nodes. The max point dose for tVMAT was lower on average (106.4% for VMAT versus 109% for 3DCRT). OAR sparing was improved with tVMAT, with a lower average V17Gy for the left lung (27.91% for VMAT versus 30.04% for 3DCRT, p and lower for V28Gy (13.75% for VMAT versus 22.34% for 3DCRT, p = 0.01). We also found a lower V35Gy for the heart on VMAT plan (p = 0.02). On the contrary, dose of contralateral breast was lower in 3DCRT than VMAT (0.59 Gy vs 3.65 Gy, p = 0.00). Conclusion: The both types of plans can meet the clinical dosimetry demands of postoperative radiotherapy for left breast cancer. The VMAT plan has a better conformity, but 3CDRT can provide a lower dose to the contralateral organs (breast and lung) to avoid the risk of secondary cancers.

Optimization oftheplanningprocesswithan in-house treatment information,management,andplanningsystem

Objective:To describe the major categories of components of an in-house treatment information,management,and planning system(TIMPS■)that were designed and built to optimize the planning process.Methods:The system was designed,from the beginning,to manage the multi-user complex process of planning and delivering external beam treatments with the eventual goal of providing one-day planning,multiple radiation modality optimization,robust optimization,4D planning,daily adaptive treatments,and treatment verification and reconstruction.A Monte Carlo based track repeating algorithm was chosen for dose simulations.The user interface was based on web applications.Results:The first set of released tools included task queuing,followed by resource scheduling calendars and planning aims.Later releases included tools for image registration,manipulating motion profiles and 4D images,segmentation,PET simulation,and portal QA.Currently under testing are plan optimization and biophysical models.Conclusions:The in-house TIMPS first entered clinical service in April of 2017 with new tools added every few months.Since implementation,the time for planning has decreased simultaneously with a reduction of errors.

Comparison of Dosiology between Three Dimensional Conformal and Intensity-modulated Radiotherapies (5 and 7 fields) in Gastric Cancer Post-surgery

The purpose of this study was to compare the dose distribution of intensity-modulated ra- diotherapy （IMRT） in 7 and 5 fields as well as 3-D conformal radiotherapy （3D-CRT） plans for gastric cancer using dosimetric analysis. In 15 patients with gastric cancer after D1 resection, dosimetric pa- rameters for IMRT （7 and 5 fields） and 3D-CRT were calculated with a total dose of 45 Gy （1.8 Gy/day） These parameters included the conformal index （CI）, homogeneity index （HI）, maximum dose spot for the planned target volume （PTV）, dose-volume histogram （DVH） and dose distribution in the organs at risk （OAR）, mean dose （Dmean）, maximal dose （Dmax） in the spinal cord, percentage of the normal liver volume receiving more than 30 Gy （V30） and percentage of the normal kidney volume receiving more than 20 Gy （V20）. IMRT （7 and 5 fields） and 3D-CRT achieved the PTV coverage. However, IMRT presented significantly higher CI and HI values and lower maximum dose spot distribution than 3D-CRT （P=0.001）. For dose distribution of OAR, IMRT had a significantly lower Dmean and Dmax in spinal cord than 3D-CRT （P=-0.009）. There was no obvious difference in V30 of liver and V20 of kidney between IMRT and 3D-CRT, but 5-field IMRT showed lower Dmean in the normal liver than other two plans （P=0.001）. IMRT revealed favorable tumor coverage as compared to 3D-CRT and IMRT plans. Specifically, 5-field IMRT plan was superior to 3D-CRT in protecting the spinal cord and liver, but this superiority was not observed in the kidney. Further studies are needed to compare differences among the three approaches.

Radiation Oncology and Medical Devices( Part 1)

Modern radiation treatments have become fairly complex and involve in utilizing a variety of medical devices to achieve the goal of providing conformal radiation dose coverage to the tumor target(s)while maximizing the sparing of normal organ structures.Recently,different forms of linear accelerators/radioactive source based machines have been invented and developed with the aim of providing improved treatments and more treatment options.Besides linear accelerators(Linac)that have been undergoing constant improvement and advancement and can deliver fairly complicated dose distribution patterns,imaging systems,computer information and calculation systems have been more and more integrated into radiotherapy processes.To bring radiotherapy to a potentially higher level,many institutions have either acquired or started to consider particle therapy,especially proton therapy.The complexity of modern radiotherapy demands in-depth understanding of radiation physics and machine engineering as well as computer information systems.This paper is intended to provide an introductory description of radiation oncology and related procedures,and to provide an overview of the current status of medical devices in radiotherapy in the United States of America.This paper covers the radiation delivery systems,imaging systems,treatment planning systems,record and verify systems,and QA systems.