Development of Practical Proton Therapy System Based on Clinical Needs / 中国医疗器械杂志

In recent years, proton therapy technology has developed rapidly, and the number of patients treated with proton therapy has gradually increased. However, the application of proton therapy technology was far from practical needs. Because of the shortage of resources and the high cost, proton therapy systems are not accessible and affordable for most patients. In order to change this situation, it is necessary to develop a new truly practical proton therapy system based on clinical needs. Conceptual design of a practical proton therapy system was proposed. Compared with the existing system, one feature of the newly designed system is to reduce the maximum energy of the proton beam to 175~200 MeV; another feature is the configuration of deluxe and economical treatment rooms, the deluxe room is equipped with a rotating gantry and a six-dimensional treatment bed, and the economical room is equipped with a horizontal fixed beam and a patient vertical rotating setup device. This design can not only reduce the cost of proton therapy system and equipment room construction, but also facilitate the hospital to choose the appropriate configuration, which will ultimately benefit more patients.

Analysis of Key Points of Technical Review of Traditional Chinese Medicine Fumigation Treatment Device / 中国医疗器械杂志

Traditional Chinese medicine fumigation device is the carrier of traditional Chinese medicine fumigation treatment. In recent years, with the rapid development of new technology and new materials, the development of fumigation device changes with each passing day, and a variety of new products continue to emerge. However, at present, the lack of corresponding evaluation norms, resulting in some difficulties in the registration, marketing, quality control, evaluation scale and other aspects of the product. Some products have many disadvantages in clinical use. From the perspective of technical review, this paper elaborates and analyzes the main concerns in technical review, such as product structure, main risks, performance requirements, clinical evaluation, etc., in order to provide a basis for the design, development, production, registration, use and post-marketing supervision of the devices.

An automatic VMAT planning method for primary liver cancer radiotherapy based on predicting the feasibility DVH / 中华放射肿瘤学杂志

Objective:To establish an automatic planning method using volumetric-modulated arc therapy (VMAT) for primary liver cancer (PLC) radiotherapy based on predicting the feasibility dose-volume histogram (DVH) and evaluate its performance.Methods:Ten patients with PLC were randomly chosen in this retrospective study. Pinnacle Auto-Planning was used to design the VMAT automatic plan, and the feasibility DVH curve was obtained through the PlanIQ dose prediction, and the initial optimization objectives of the automatic plan were set according to the displayed feasible objectives interval. The plans were accessed according to dosimetric parameters of the planning target volume and organs at risk as well as the monitor units. All patients′ automatic plans were compared with clinically accepted manual plans by using the paired t-test. Results:There was no significant difference of the planning target volume D 2%, D 98%, D mean or homogeneity index between the automatic and manual plans ((58.55±2.81) Gy vs.(57.98±4.17) Gy, (47.15±1.58) Gy vs.(47.82±1.38) Gy, (53.14±0.95) Gy vs.(53.44±1.67) Gy and 1.15±0.05 vs. 1.14±0.07, all P>0.05). The planning target volume conformity index of the manual plan was slightly higher than that of the automatic plan (0.77±0.08 vs. 0.69±0.06, P<0.05). The mean doses of normal liver, V 30Gy, V 20Gy, V 10Gy, V 5Gy and V< 5Gy of the automatic plan were significantly better than those of the manual plan ((26.68±11.13)% vs.(28.00±10.95)%, (29.96±11.50)% vs.(31.89±11.51)%, (34.88±11.51)% vs.(38.66±11.67)%, (45.38±12.40)% vs.(50.74±13.56)%, and (628.52±191.80) cm 3vs.(563.15±188.39) cm 3, all P<0.05). The mean doses of the small intestine, the duodenum, and the heart, as well as lung V 10 of the automatic plan were significantly less than those of the manual plan ((1.83±2.17) Gy vs.(2.37±2.81) Gy, (9.15±9.36) Gy vs.(11.18±10.49) Gy, and (5.44±3.10) Gy vs.(6.25±3.26) Gy, as well as (12.70±7.08)% vs.(14.47±8.11)%, all P<0.05). Monitor units did not significantly differ between two plans ((710.67±163.72) MU vs.(707.53±155.89) MU, P>0.05). Conclusions:The automatic planning method using VMAT for PLC radiotherapy based on predicting the feasibility DVH enhances the quality for PLC plans, especially in terms of normal liver sparing. Besides, it also has advantages for the protection of the intestine, whole lung and heart.

Quantitative comparison of volumetric-modulated arc therapy plans for liver cancer using flattening filter-free and flattening filter modes based on plan quality metric ( PQM) / 中华放射医学与防护杂志

Objective To quantitatively assess the plan quality of conventional fractionated volumetric modulated arc therapy ( VMAT ) plans for liver cancer treatments using flattening filter-free (FFF) and flattening filter (FF) modes based on plan quality metric (PQM). Methods A total of ten patients with liver tumor were selected. The patients were planned in FF and FFF mode of 6 MV X-ray respectively. The dose distribution of the planning target volume ( PTV) and the organ at risk ( OAR) were evaluated, and the monitor units ( MUs) and the beam on time ( BoT) were compared. According to the clinical requirements, a PQM with 16 submetrics was defined to evaluate the plan quality of the two modes. Results The maximal dose of FFF plan was less than that of FF plan (t =3.828, P <0.05). The normalized volume of 5 Gy ( V5 ) and mean dose ( Dmean ) of the normal liver of FFF plan were lower than those of the FF plan (t=2.716, 3.007, P<0.05). The average MU of FFF plan [(574 ± 130) MU] was higher than that of FF plan [(518 ± 81) MU](t= -2. 782,P<0. 05), while the average BoT of FFF plan [(108 ±36)s] was significantly lower than that of FF plan [(160 ±29) s](t=6.767,P<0.05). The score of FFF plan was higher than that of FF plan (t= -2.746, P<0.05). Conclusions FFF mode can better protect the OAR at low dose levels. The MU of FFF mode plan were higher, but the beam on time was significantly lower than FF mode plan. With reference to the PQM evaluation criteria, the overall plan quality of the FFF mode was slightly higher.

Progress in charged particle therapy / 中华放射肿瘤学杂志

Charged particle therapy offers a better effect and obvious dosimetric and biological advantages over conventional radiotherapy in tumor control.Charged particles form Bragg peak in the dose distribution in tissue, enable most of energy to be deposited in the target region, and thus enhance tumor control and reduce the damage to normal tissues surrounding the tumor.With the increasing demand for charged particle therapy and the advances in particle accelerator, particle therapy technology is developing rapidly.The core apparatus of particle therapy facility is particle accelerator, and the accelerator type, particle type, and implementation technique determine the performance and therapeutic effect of the facility.This article provides a detailed comparative analysis of various particle therapies.Statistical data show that proton therapy is dominant in particle therapy, and high construction difficulty, large facility size, and extremely high cost have limited the development of heavy ion therapy.Nowadays, there are still some technical problems regarding charged particle therapy, and more clinical trials are required.

Interventional mechanical thrombectomy treatment for chronic vascular thrombus / 介入放射学杂志

Objective To investigte the possibility of interventional mechanical thrombectomy dealing with chronic vascular thrombus, and assessing its curative effects. Methods Twenty three cases included 17 males 6 females, and aged from 46 to 80 year with a mean of 64.8. All patients were coinsided with MRA, vascular ultrasound and angiography, in which 12 patients with chronic heart and vascular disease, and 11 patients with serious diabetes. Thrombi were located in iliac artery ( n=9,L=4,R=3 , bilaterals=2), femoral artery( n =2), populiteus artery ( n =2), popliteus artery( n =3), iliac vein ( n =7, L=5,R=2), portal vein ( n =1). The length of thrombi varied from 3 to 8 cm, and the diameter from 5 to 10mm.Filter should be placed in inferior cava vein before venous thrombus treatment ( n =7). Mechanical thrombectomy was undertaken as following: ATD ( n=9, Vein=7), PTD( n =2), and Oasis( n =1). After guide wire passing through thrombus segment, Oasis was inserted for remove thrombus. Urokinase (500 000U) was usually administered for catheter directed thombolysis before/during mechanical thrombectomy. Stent should be placed in the segment if stenosis was confirmed after thrombectomy angiography. Drugs were used after thrombectomy including thromboyltic drug, heparinzed anticoagulation and changing microcirculation. Vascular ultrasound, reconstruction CTA and clinical follow up had all been carried out. Results 12 cases (85.7) were undergone successfully thrombectomy. One case failured with portal vein thrombus formation, the other with multiple segments involvement in femoral artery was treated by combined ATD and Oasis. Sy mptoms of 15 cases were either released or disappared, including ischemia, swelling and motion limitations. The patency shown by vascular ultrasound follow up were 100% in three months, 85.4% in six months, 73.2% in twelve months, with simultaneously blood flow improvement to normal and obviously corrected 76.5%,65.4% 60.1% in 3,6,12 month respectively.Conclusions Interventional mechanical thrombectomy is a new choice of treating chronic vascular thrombus with its direct curative effects, but still needs long term follow up.