Will High Dose Rate Interstitial Brachytherapy Be a Surrogate to Surgery in Early Mobile Squamous Cell Carcinoma of Tongue—An Indian Experience

The study was intended to highlight functional outcome and survival advantage when High Dose Rate (HDR) interstitial implant was used for anterior 2/3rd tongue, either as a primary or as boost depending upon stage of disease. Materials and Methods: Fifty-one patients with squamous cell carcinoma of anterior 2/3rd tongue received interstitial brachytherapy either as primary or as boost with Iridium 192 remote after loading high dose rate (Microselectron or Gamma MediX) machines from November 2008 to September 2013. Age group ranged from 32 to 73 years, mean 52.1. Of these 51, 37 were males and 14 were females. 8 patients belonged to Stage I, 18 from Stage II and 28 patients were Stage III. Stage I patients received primary brachytherapy alone of dose 38.50 Gy to 40 Gy and fraction dose ranged from 250 cGy to 350 cGy. Stage II and Stage III patients received external beam radiation of dose 44 Gy/200cGy per fraction for 22 fractions followed by spinal cord sparing for 6 Gy/200cGy per fraction for 3 fractions. Brachytherapy boost of dose 21 Gy was delivered after external beam radiation. Stage III patients received concurrent chemotherapy with Injection Cisplatin along with external beam radiotherapy 44 Gy/200cGy per fraction for 22 fractions followed by spinal cord sparing for 6 Gy/200cGy per fraction for 3 fractions. Brachytherapy boost of dose 21 Gy was delivered after external beam radiation. 55% of patients were habituated to tobacco and alcohol in one form or the other or both. Surprisingly 45% of patients were nonsmokers and non-alcoholic. Results: Follow-up period ranged from eight months to sixty months. 42 patients had complete response. 9 patients had residual disease. 2 patients died due to non-cancerous cause though they had excellent local control, one with pulmonary tuberculosis and the other with massive Myocardial Infarction. 2 patients died due to disease progression. Overall complete response rate was 82.35%. Those patients who had good coverage index and conformal index had good response compared to those patients with lesser these values. Conclusion: It is surprising to observe from the study that oral cavity cancers are not uncommon in non-smokers and non-alcoholics. Overall complete response of 82% is comparable to any other study quoted in literature. Surgery offers same cure rate but at the rate of organ loss and functional impairment. Organ preservation with good functional outcome is possible in radiotherapy unlike surgery. This study proves brachytherapy can be considered as a surrogate to surgery in early stage tongue cancers with good functional outcome and with lesser morbidity.

Organ at Risk Doses during High Dose Rate Intracavitary Brachytherapy for Cervical Cancer: A Dosimetric Study

Background: Treatment of Cervical cancer includes a combination of external beam radiotherapy (EBRT) with intracavitary brachytherapy (ICBT). ICBT helps to boost radiation dose to primary disease. Organs like rectum, bladder, sigmoid and small bowel lie close to the cervix region and these organs receive dose from EBRT as well as ICBT and we want to know the dose to these organ at risk (OAR). Materials & Methods: Dosimetric details of 174 ICBT applications done in 58 patients were retrospectively analysed. All patients received EBRT dose of 50.4 Gy in 28 fractions. All patients had ICBT, three sessions with 7 Gy prescribed to point A. Dosimetric data including dose to right and left point A and dose to OARs were recorded from Oncentra Planning System. Results: Mean dose to point A on right side was 6.89 Gy and left side was 6.91 Gy. Mean D2cc dose to rectum, bladder, sigmoid and small bowel was 3.5 Gy, 5.25 Gy, 4.75 Gy and 4.2 Gy respectively. Mean EQD2 dose combining EBRT and ICBT in point A was 78.7 Gy on right side and 79 Gy on left side. Mean EQD2 doses to D2cc of rectum, bladder, sigmoid and small bowel was 62 Gy, 74.4 Gy, 70.5 Gy and 66.5 Gy respectively. Conclusion: From the results of this dosimetric study it is evident that OARs like rectum, sigmoid, bladder & bowel are receiving only acceptable doses of radiation using point A prescribed CT based ICBT planning. Hence with regards to OAR doses, CT based ICBT planning with dose prescribed to point A is a feasible option.

Commissioning and Optimization of a Total Skin Electron Therapy Technique Using a High Dose Rate Electron Facility

Total skin electron therapy (TSET) is used for the treatment of Mycosis Fungoides. Several tech-niques have been developed, in order to achieve homogeneous dose distribution over the complete body surface. To implement a TSET technique, one has to optimize a variety of parameters. Monte Carlo simulation of TSET can facilitate this optimization. The aim of this study was to commission and optimize a TSET technique using the 4 and 6 MeV electron and the high dose rate facility on the Elekta Precise accelerator. The EGS4nrc/BEAMnrc Monte Carlo code was used. The beam data were calculated and measured at two different scoring planes for a single beam. The Model was validated by comparing the simulation with measurements. Two different vertical angles were used to obtain a uniform dose. The angle was optimized for best dose uniformity. The Rando phantom is placed on a rotating platform and rotates 60 degrees apart to facilitate the six patient position orientations. The doses delivered in a phantom by complete treatment were measured with Kodak EDR2 films and TLDs. The dose distribution varied among various scanning directions by 2 - 3 mm and 3 - 4 mm for 4 and 6 MeV respectively. The composite percentage depth dose of all six dual fields for the 4 and 6 MeV yielded an R80 of ~4 mm and ~6 mm, respectively. Dose uniformity was ±6% for 4 MeV and ±5% for 6 MeV. The bremsstrahlung contamination was 0.9% - 1.3%. Good agreements were found with published literature and inline with international protocols.

High Dose Rate (HDR) Brachytherapy for Mycosis Fungoides of the Wrist

Mycosis fungoides (MF) is the most common cutaneous T-cell lymphoma accounting for approximately half of all cutaneous T-cell lymphomas. Radiation therapy is an effective treatment for early stage MF and has been shown to result in long-term disease-free intervals, with even curative potential. Radiation is also effective as palliative treatment for the localized lesion resistant to the topic or other treatments. In the current study, we report using high dose rate (HDR) radiation treatment for a patient with resistant mycosis fungoides involving the wrist. We report a convenient treatment with an ideal radiation dose distribution, and a excellent clinical outcome.

High-dose-rate intraluminal brachytherapy during preoperative chemoradiation for locally advanced rectal cancers

AIM:To determine the feasibility and safety of high dose rate intraluminal brachytherapy(HDR-ILBT) boost during preoperative chemoradiation for rectal cancer.METHODS:Between 2008 and 2009,thirty-six patients with locally advanced rectal cancer(≥ T3 or N+),were treated initially with concurrent capecitabine(825 mg/m2 oral twice daily) and pelvic external beam radiotherapy(EBRT)(45 Gy in 25 fractions),then were randomized to group A;HDR-ILBT group(n = 17) to receive 5.5-7 Gy×2 to gross tumor volume(GTV) and group B;EBRT group(n = 19) to receive 5.4 Gy×3 fractions to GTV with EBRT.All patients underwent total mesorectal excision.RESULTS:Grade 3 acute toxicities were registered in 12 patients(70.6%) in group A and in 8(42.1%) in group B.Complete pathologic response of T stage(ypT0) in group A was registered in 10 patients(58.8%) and in group B,3 patients(15.8%) had ypT0(P < 0.0001).Sphincter preservation was reported in 6/9 patients(66.7%) in group A and in 5/10 patients(50%) in group B(P < 0.01).Overall radiological response was 68.15% and 66.04% in Group A and B,respectively.During a median follow up of 18 mo,late grade 1 and 2 sequelae were registered in 3 patients(17.6%) and 4 patients(21.1%) in the groups A and B,respectively.CONCLUSION:HDR-ILBT was found to be effective dose escalation technique in preoperative chemoradiation for rectal cancers,with higher response rates,downstaging and with manageable acute toxicities.

Dose-volume parameters and clinical outcome of CT-guided free-hand high-dose-rate interstitial brachytherapy for cervical cancer

Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-dose- rate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach. Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer. Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied. With a median of 5 (range, 4-7) implanted needles for each patient, the median dose of brachytherapy alone delivered to 90% of the target volume (D90 ) was 45 (range, 33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range, 20-36) Gyα/β10 for intermediate-risk clinical target volume (IR-CTV). The percentage of the CTV covered by the prescribed dose (V100 ) of HR-CTV with brachytherapy alone was 81.9%-99.2% (median, 96.7%). With an additional dose of external beam radiotherapy (EBRT), the median D90 was 94 (range, 83-104) Gyα/β10 for HR-CTV and 77 (range, 70 -87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100 ) was 75 (range, 66-84) Gyα/β10 for HR-CTV and 65 (range, 57-73) Gyα/β10 for IR-CTV. The minimum dose to the most irradiated 2 cc volume (D2cc ) was 73-96 (median, 83) Gyα/β3 for the bladder, 64-98 (median, 73) Gyα/β3 for the rectum, and 52-69 (median, 61) Gyα/β3 for the sigmoid colon. After a median follow-up of 15 months (range, 3 -24 months), two patients experienced local failure, and 1 showed internal iliac nodal metastasis. Despite the relatively small number of needles used, CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.

An Innovative Concept of High-Dose-Rate (HDR) Intracavitary Brachytherapy with an Intrauterine Inflatable Balloon for Endometrial Carcinoma

Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman capsules, and an inflatable intrauterine balloon to assess the dose homogeneity and conformality in the definitive treatment of inoperable endometrial cancer. Methods and Materials: Patients’ informed-consent was obtained. Dosimetric analyses were performed using four different after-loading applicators to assess the dose homogeneity and conformality of isodose to the three-dimensional (3-D) shape of the target volume (uterus) based on CT data in four patients (n = 4). The single tandem and double tandems were standard Fletcher-type (Nucletron Corporation, Columbia, MD). Heyman capsules were the disposable after-loading type (Radiation Products Design, Inc., Albertville, MN). The inflatable balloon with a central bi-lumen catheter was the Mammo Site Radiation Therapy System (Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast brachytherapy. Treatment planning and dosimetric analyses for all four techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron Corporation). Results: The average dose gradient within the target (uterine wall) is highest with the tandem methods, followed by Heyman capsules. The intrauterine balloon method showed the least dose gradient across the uterine wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50 for single tandem, double tandem, Heyman capsules, and intrauterine balloon respectively. Conclusions: The intra-uterine inflatable balloon appears to have the best overall dosimetric advantages for the treatment of the uterine wall. Furthermore, the potential ease of use, shorter time of applicator placement, and better patient comfort warrant further investigation and subsequent clinical implementation.

The Experience of Pain and Anxiety in Cervical Cancer Patients Undergoing Multiple Fraction High-Dose Rate Brachytherapy: A Prospective Observational Study

Purpose: To evaluate the anxiety and pain levels of cervical cancer patients undergoing intracavitary multifraction high-dose rate (HDR) brachytherapy, as part of a process to develop guidelines for quality patient-centered care. Methods: Cervical cancer patients (n = 31) undergoingmultiple fraction HDR brachytherapy treatment at the National Institute of Oncology in Rabat (Morocco) completed ratings of pain and anxiety intensity using 11-point verbal analog scales, at 6 key time points over 2 brachytherapy insertion procedures and 4 brachytherapy fractions. Women were evaluated for psychological status at baseline before starting the brachytherapy process using the Hospital Anxiety and Depression Scale (HADS). Scores were grouped as follows: 0 - 7 = normal, 8 - 10 = borderline, 11 - 21 = abnormal. Factors that could affect anxiety levels such as education level, relationship status, number of pregnancies and prior surgical history were documented. Results: Between July and August 2020, 31 women with a median age of 49.6 years were evaluated (range: 27 - 70). The HADS score identified depression in 5 patients (16.1%) and anxiety in 12 patients (38.7%). Throughout both treatment procedures, anticipatory anxiety was reported, with a maximum intensity in the operating room during spinal anesthesia (3.23 ± 1.7) and during applicator insertion (2.97 ± 2.4). Moderate-to-severe anxiety scores were reported in 25.8% and 22.6% of patients respectively. Level of education showed a significant correlation with anxiety scores (p = 0.027). Pain increased significantly during the procedure (p ± 1.4) and applicator removal (4.74 ± 1.5) turned out to be the most painful parts of the procedure. No correlation was found between pain and anxiety levels. Conclusion: Intracavitary multifraction high-dose rate brachytherapy is associated with mild to moderate levels of pain and anxiety, although a subset of patients reported more severe symptoms and may require additional medical and psychological support, with particular emphasis on bed-rest duration and applicator removal. The development of effective interventions (both pharmacological and non-pharmacological) is needed to improve women’s experiences of brachytherapy for locally advanced cervical cancer.

Experiences of Women Receiving Multifraction High Dose-Rate Brachytherapy for Cervical Cancer: A Prospective Qualitative Study

Objective: The aim of this study was to establish cervical cancer patients’ expectations and experiences during high dose-rate (HDR) intracavitary brachytherapy procedure, as part of a process to develop guidelines for quality patient-centered care. Methodology: A prospective, qualitative study with a descriptive phenomenological approach was used. Purposive sampling was carried out to recruit 31 women undergoing HDR brachytherapy for cervical cancer from June to August 2020 at the National Institute of Oncology in Rabat. Semi-structured, one-to-one interviews guided by a theme list were conducted by a female radiation oncologist in Arabic before, during and after treatment. The following aspects were discussed: expectations, experiences in the waiting room, in the treatment room, and suggestions for improvement. Data was transcribed, translated and thematic analysis performed. Results: Most of the patients felt unprepared and did not have a clear understanding of brachytherapy. Brachytherapy was a difficult experience causing fear and anxiety throughout treatment. Most women dreaded the procedure, before receiving the first treatment and even after having had one. Pain was a major problem for the participants. Some women compared this pain to childbirth, a process they preferred to brachytherapy. Patients agreed that the preventative medication received was not efficient to relieve the pain. Despite these negative experiences, patients were left with a positive outlook. Dialogue with the healthcare professionals, support from their family and fellow patients, envisaged outcomes and desires to heal were used to cope, whilst faith and spirituality gave them strength to endure the procedure. Conclusion: Women undergoing uterovaginal brachytherapy for cervical cancer experience pain and emotional distress. Providing patients with adequate information, more sensitive support during the procedure and debriefing afterwards could lessen feelings of fear and anxiety. Our findings advocate for the revision of pain management protocols. Further studies should be carried out to define patient-centered recommendations and provide quality care to this group of women.

Natural background radiation dose rate levels and incidences of reproductive abnormalities in high radiation area in Abeokuta, Southwestern Nigeria

A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation exposure on reproductive abnormalities in the city. From the delivery record of 11,923 births in the period under study, a total number of 485 incidences of reproductive abnormalities were recoded. These incidences comprise 228 multiple births, 190 still births and, 67 premature births. Using the available terrestrial gamma radiation exposure data for the city and different reproductive abnormalities, regression assessment was carried out using the Pearson Product Moment (PPM) correlation statistics. The correlation showed that the incidences of reproductive abnormalities and the radiation dose levels were negatively correlated and correlation coefficient values were very low for each of the reproductive abnormalities considered. Factors such as socio-economic potentials of patients, dietary and other environmental factors may have substantial influence on the reproductive defects in the area other than radiation. However, the present study has added to the radiometric information needed in understanding the relationship between natural outdoor radiation exposure and occurrences of reproductive abnormalities in areas of high radiation in the country.

Effect of ionizing radiation on dual 8-bit analog-to-digital converters (AD9058) with various dose rates and bias conditions

The radiation effects on several properties （reference voltage, digital output logic voltage, and supply current） of dual 8-bit analog-to-digital （A/D） converters （AD9058） under various biased conditions are investigated in this paper. Gamma ray and 10-MeV proton irradiation are selected for a detailed evaluation and comparison. Based on the measurement results induced by the gamma ray with various dose rates, the devices exhibit enhanced low dose rate sensitivity （ELDRS） under zero and working bias conditions. Meanwhile, it is obvious that the ELDRS is more severe under the working bias condition than under the zero bias condition. The degradation of AD9058 does not display obvious ELDRS during 10-MeV proton irradiation with the selected flux.

大功率花瓣加速器X射线闪光放射治疗设备设计研究

目的:研究设计一种用于超高剂量率的闪光放射治疗(Flash-RT)设备,用于超高剂量率Flash-RT的机制研究。方法:Flash-RT设备的设计基于大功率花瓣加速器技术路线,可实现Flash-RT对超高剂量率及多照射角度的需求。从设备总体设计、主要组件及特点、束流动力学设计、移动及初步实验平台搭建等方面开展相应设计与研究。结果:设计的Flash-RT设备剂量率在距离靶点0.8 m处可达到100 Gy/s,并且容易实现多角度的放射治疗方式。结论:基于大功率花瓣加速器技术路线设计的X射线设备,可实现超高剂量率的医用Flash-RT设备机制的研究。

闪光放射治疗(Flash-RT)技术的研究进展

经过多年发展,精准放射治疗技术已广泛应用,但现有技术仍受限于正常组织耐受剂量的限制,无法实现肿瘤治疗的最佳目标。闪光放射治疗(Flash-RT)是一种以超高剂量率射束(UHDR)进行照射的放射治疗技术,能够在显著降低正常组织辐射损伤的同时,最大限度地治疗肿瘤。但直到目前,Flash-RT的生物学机制、关键物理参数及触发机制等尚不明确,其原理及临床转化应用仍处于研究阶段。本综述通过归纳Flash-RT相关研究,阐明Flash-RT研究的技术进展及临床转化应用。

闪光放射治疗对比常规放射治疗在放射性肺损伤中的机制探索

放射治疗是治疗肺癌的重要手段,但容易造成肺部损伤并降低患者生活质量。闪光放射治疗(Flash-RT)因其极短的辐射时间和高剂量率备受关注,其在保证肿瘤治疗强度的同时,能够减少正常组织毒性反应。Flash-RT能否减少放射性肺损伤成为近年重点研究课题。本综述基于文献分析方法,通过检索国内外相关文献,系统评估Flash-RT与常规剂量率放射治疗对肺损伤的影响及其机制。通过综述Flash-RT与常规剂量率放射治疗对肺损伤的影响及其机制对比,为肺癌患者的治疗提供科学依据。Flash-RT与常规剂量率放射治疗相比,可以显著减少肺损伤并提高患者生活质量。未来仍需深入探索Flash-RT的机制,开发适用于不同肿瘤的Flash-RT装置和开展大规模临床研究。

闪光放射治疗(Flash-RT)在肿瘤治疗中的研究进展

闪光放射治疗(Flash-RT)作为放射治疗技术基础领域的关键性突破,可能引起放疗领域新的大变革。本文综述了Flash-RT在肿瘤治疗中应用和机制探索的最新研究进展。目前研究发现无论是电子束和光子Flash-RT还是质子FlashRT相较于常规剂量率放疗均可以降低对正常组织的损伤,但相关机制还未明确,包括但不限于氧耗竭、DNA损伤、细胞衰老、凋亡和免疫反应等。Flash-RT在肿瘤组织与正常组织损伤间的差异进一步减少了放疗的局限性,相较于常规放疗减少了不良反应和并发症,具有广阔应用前景。

高气压电离室环境适应性、可靠性和计量特性的设计与测试

为建立用于环境水平γ辐射场所剂量率监测用高气压电离室,从电离室外壳、探头结构、电子学系统等方面开展优化设计,提升设备的环境适应性、电磁兼容性以及可靠性。参照标准方法,产品样机在第三方测试机构开展通用质量性能测试,测试结果表明:该产品工作及贮存温度范围-10℃~45℃,湿度范围≤93%RH;具备一定抗振动冲击能力,满足GB/T 8993-1998中运输环境条件严酷等级2M1要求;电磁兼容性中静电放电抗扰度、射频电磁场辐射抗扰度满足GB/T 17626.2-2018、GB/T 17626.3-2016的相关要求;可靠性满足MTBF≥1000 h的要求,该产品的环境适应性、电磁兼容性、可靠性符合计量级产品需要,可作为便携式辐射剂量仪用于无气候防护场所。自研的高气压电离室可携带至现场作为环境水平空气比释动能高准确度工作计量器具使用,开展辐射剂量监测。

高速率生理盐水联合高强度深度学习重建算法对“三低”头颈部CTA图像质量的影响

目的 探讨高速率生理盐水联合高强度深度学习重建(High-Strength Deep Learning Image Reconstruction,DLIR-H)算法对“三低”(低管电压、低对比剂用量、低对比剂注射速率)头颈部CT血管造影(CT Angiography,CTA)图像质量的影响。方法 前瞻性收集于我院行头颈部CTA检查的90例患者,随机分为A、B、C组,每组各30例。A组以4.5 mL/s的速率注射50 mL对比剂,以3.0 mL/s的速率注射40 mL生理盐水,采用120 kVp,使用60%自适应迭代重建(Adaptive Statistical IterativeReconstruction-V,ASIR-V)算法重建;B组以3.0mL/s的速率注射30mL对比剂,以3.0mL/s的速率注射40mL生理盐水,采用80 kVp,使用60%ASIR-V算法重建;C组以3.0 mL/s的速率注射30 mL对比剂,以5.0 mL/s的速率注射40 mL生理盐水,采用80 kVp,使用DLIR-H算法重建。比较3组图像间的CT值、图像噪声(Standard Deviation,SD)、信噪比(Signal to Noise Ratio,SNR)、对比噪声比(Contrast to Noise Ratio,CNR)、CT容积剂量指数(CT Dose Index Volume,CTDIvol)及CT剂量长度乘积,比较3组图像质量的主观评分。结果 3组图像的CT值、SD值、SNR及CNR的差异均具有统计学意义(P<0.001)。C组在上腔静脉处CT值低于A、B组,其余各目标血管CT值、SNR及CNR均高于A、B组。C组各目标血管SD值小于B组,差异具有统计学意义(P<0.05);C组与A组的SD值差异无统计学意义(P>0.05)。C组CTDIvol、有效辐射剂量、对比剂用量较A组分别降低了55%、54%、40%。3组图像的主观评分差异具有统计学意义(P<0.001),C组与A组的差异无统计学意义(P>0.05)。结论 在“三低”技术下高速率生理盐水联合DLIR-H算法在头颈部CTA中的应用不仅能获得与常规剂量相当的图像质量,还可以使辐射剂量、对比剂用量和对比剂注射速率均明显减少。

FLASH放射生物学机制及治疗计划研究进展

近年来,一项被称为FLASH放疗的新技术具有将辐射的治疗增益比推向一个新高度的潜力。FLASH放疗是一种以超高剂量率照射为主要特征的放疗技术,能显著减轻辐射对正常组织的损伤,同时保留辐射对肿瘤的杀伤能力。一方面,作为一种新兴的放疗技术,FLASH放疗的生物学机制尚未被阐明,这阻碍了其临床转化;另一方面,超高剂量率照射技术的临床应用也存在许多技术困难。本综述通过归纳FLASH放射生物学机制的研究进展,总结FLASH放疗治疗计划所面临的困难及可能的解决方案,旨在为后续FLASH放疗的临床转化提供参考。

局限期前列腺癌高剂量率近距离治疗联合外照射的效果分析

目的分析高剂量率近距离治疗(high-dose rate brachytherapy,HDR-BT)联合外照射在局限性前列腺癌患者中的疗效。方法回顾性分析2015年1月至2019年1月收治的23例局限性中高危前列腺癌患者的临床资料,其中中危患者4例,高危患者19例。初始诊断最高PSA为6.6~64.3 ng/ml。患者均接受HDR-BT联合外照射及内分泌治疗,治疗后随访观察无生化进展生存率、无远处转移生存率、疾病特异性生存率、总生存率及并发症。结果本组23例明确诊断后即行前列腺癌内分泌治疗,后随即行HDR-BT联合外照射,HDR-BT处方剂量:18 Gy/6 Gy/3 f,外照射处方剂量:45~50 Gy/1.8~2.0 Gy/25 f,治疗后随访14~56个月。4例出现生化复发,2例出现远处转移,2例死亡,其中1例死于前列腺癌,1例死于其他非相关疾病。治疗后总体无生化进展生存率为82.6%,无远处转移生存率为91.3%,总生存率为91.3%,疾病特异性生存率为95.6%;3年无生化进展生存率、无远处转移生存率、总生存率及疾病特异性生存率分别为85.5%、89.3%、92.9%及92.9%。18例(78.2%)患者出现不同程度的下尿路刺激症状,未发生严重并发症。结论HDR-BT联合外照射治疗局限性中高危前列腺癌疗效肯定、创伤小,术后并发症少。

局部晚期非小细胞肺癌后装插植放疗

大多数Ⅲ期非小细胞肺癌(NSCLC)患者因肿瘤扩散或合并症而不适合手术。原发病灶内的局部区域控制的失败,仍然是不可切除的局部晚期NSCLC放疗后治疗失败的主要原因。对于NSCLC,肿瘤控制率随着原发灶放疗的生物效应剂量(BED)升高而增加。接受30 Gy单次放疗(BED=120 Gy)的患者有98%的局部控制率(LC)。另一项剂量反应分析显示,在120 Gy可能是比较合适和稳定的剂量。高剂量率(HDR)近距离放射疗法,又称后装插植放疗,其优势在于可以在单次分割照射中向靶区肿瘤给予高辐射剂量。随后剂量迅速下降,使照射到危及器官(OARs)的剂量保持较低的水平。此外,插植放疗抑制了肿瘤细胞的加速再增殖,导致其致死性损伤,并解决了由于器官运动或摆位确定性造成的目标偏离,避免了对OARs的不必要照射。在免疫治疗时代,胸部放疗对于保障NSCLC长期生存越发重要。HDR近距离放疗联合免疫治疗可能带来新的突破。前期临床试验也观察到良好的临床存活率和较低的急性和迟发毒性,为局部晚期NSCLC提供了一种新的治疗策略。