局部晚期宫颈癌腔内放疗联合组织间插植的剂量学研究

目的 比较局部晚期宫颈癌单纯腔内放疗与腔内联合组织间插植放疗的剂量学差异。方法 2016年5月—2017年3月局部晚期宫颈癌患者共35例,均行根治性放疗,治疗方法为外照射+腔内联合组织间插植放疗。调强放射治疗处方剂量为46.8~50.4 Gy/26~28次,1.8 Gy/次。腔内联合组织间插植放疗剂量为7 Gy/次,1次/周,共4次。同一患者首先置入三管式后装放疗施源器,采集CT图像制定治疗计划,取出三管式施源器后,置入宫腔管并植入插植针,再次采集图像制定放疗计划。分别评价比较两组计划中靶区及危及器官的受照剂量差别。结果 共制定212次后装放疗计划,其中单纯腔内治疗计划106例,腔内联合组织间插植治疗计划106例。腔内联合组织间插植放疗组计划较单纯腔内放疗组的靶区剂量明显升高,高危临床靶区（CTV）的D₉₀、中危CTV的D₉₀均显著增高（t=-6.01、-2.73,P<0.05）,膀胱、直肠、乙状结肠的D_{2 cm³}显著降低（t=3.07、4.52、2.91,P<0.05）。结论 局部晚期宫颈癌应用腔内联合插植放疗可以明显提高靶区剂量,并降低危及器官膀胱、直肠和乙状结肠的受照剂量。     

三维适形放疗与容积调强放疗治疗局部晚期宫颈癌比较研究

目的探讨三维适形放疗(3D-CRT)及容积调强放疗(VMAT)剂量分割方案的改变对靶区覆盖指数以及危险器官受量的影响。方法选取辽宁省肿瘤医院放疗科自2017年6月至2018年12月收治的81例局部晚期宫颈癌患者为研究对象。根据外照射治疗方案选择不同将所有患者分为A组(n=39)和B组(n=42)。A组采用三维适形放疗联合三维近距离治疗;B组采用容积调强放疗联合三维近距离治疗。比较两组患者靶区剂量覆盖指数及危及器官(OAR)受量。结果 B组靶区适形度指数(CI)显著高于A组,两组比较,差异有统计学意义(P<0.05);两组患者靶区均不匀性指数(HI)比较,差异无统计学意义(P>0.05)。B组的膀胱、结直肠、小肠受量均显著低于A组,两组比较,差异均有统计学意义(P<0.05)。结论宫颈癌容积调强放疗联合三维近距离治疗与三维适形放疗联合三维近距离治疗均能得到较好的靶区覆盖,使肿瘤得到良好的局部控制,但容积调强放疗联合三维近距离治疗的膀胱、结直肠、小肠等OAR受量更低。临床上应根据患者实际情况选择使用。     

宫颈癌腔内联合插植近距离放疗中卵圆体的剂量学贡献研究

目的:探讨宫颈癌腔内联合组织间插植近距离放射治疗中卵圆体的剂量学贡献。方法:选取2015—2017年间在吉林大学中日联谊医院接受根治性放射治疗的局部晚期宫颈癌患者20例,患者病理分期依据国际妇产科协会(FIGO)2009年分期标准为Ⅱ A、Ⅱ B和Ⅲ B期。外照射治疗45 Gy/1....     

三种局部补量技术在晚期宫颈癌放疗中的应用研究

目的 探讨三维腔内联合组织间插植（IC/IS BT）、三维腔内（ICBT）联合调强 （ICBT+IMRT）以及单纯IMRT技术在局部晚期宫颈癌治疗中的剂量学差异。方法 选取16例接受三维近距离治疗的局部晚期宫颈癌患者,在原IC/IS BT计划的基础上分别设计ICBT+IMRT和单纯 IMRT计划,研究3种计划中肿瘤靶区和危及器官（OARs）的剂量学差异。结果 共制定75个后装治疗计划,其中IC/IS BT、ICBT+IMRT和单纯 IMRT各25个。 ICBT+IMRT与IC/IS BT计划的靶区体积剂量D₉₀差异无统计学意义（P>0.05）, OARs的剂量比较低。单纯IMRT计划中OARs受量相对较大,且V₆₀明显偏高（与IC/IS BT相比,t=6.77、10.37、4.61、2.83,P<0.05）。结论 ICBT+IMRT计划的肿瘤靶区剂量覆盖较好且OARs受剂量低,可以作为IC/IS BT替代治疗手段。单纯 IMRT技术虽然靶区覆盖度较好,但OARs保护差,不适用于晚期宫颈癌的局部补量治疗。     

局部晚期胰腺癌调强放疗与三维适形放疗剂量学比较及临床疗效分析

目的 比较局部晚期胰腺癌放疗中三维适形放疗(3 D-CRT)与调强放疗(IMRT)技术的剂量学差异,观察IMRT联合吉西他滨局部化疗的临床疗效.方法 选择10例局部晚期胰腺癌患者的CT定位图像,分别设计3D-CRT和IMRT计划,利用剂量体积直方图(DVH)评价2种治疗计划的剂量.回顾性收集2008年5月至2010年5月符合入组标准的25例接受IMRT联合吉西他滨局部介入治疗的局部晚期胰腺癌患者(联合治疗组),选择同时期入院的仅接受吉西他滨局部介入治疗的25例晚期胰腺癌患者(单化组)做对比研究,比较2组的临床疗效及不良反应.结果 IMRT计划中十二指肠、肝脏、胃、双肾、小肠的平均剂量及高剂量区照射体积明显低于3D-CRT计划.联合治疗组与单化组1、2年生存率分别为60％、28％和36％、12％,中位生存期分别为15个月和10个月(x2 =4.16,P＜0.05),有效率分别为64％和32％(x2 =5.13,P＜0.05).联合治疗组上消化道反应发生率高于单化组(Z=-2.35,P＜0.05),而骨髓抑制、肝肾功能损害情况差异无统计学意义.结论 与三维适形放疗相比,调强放疗在保证靶区高剂量的情况下降低危及器官的剂量,联合吉西他滨局部化疗可显著提高局部晚期胰腺癌患者的生存率,延长的中位生存时间,且不良反应轻微.     

3D打印模板应用于局部晚期宫颈癌后装放疗的剂量学研究

目的 局部晚期宫颈癌后装放疗应用3D打印微创导向模板的剂量学研究。方法 本研究为前瞻性研究,选取2016年5月-2019年8月就诊河北省沧州中西医结合医院的局部晚期宫颈癌患者共68例,均为偏心性或外照射后仍有巨大肿块（肿瘤直径>5 cm）残存的患者,外照射采用调强放疗,后装治疗方法为腔内联合组织间插植放疗,高危临床靶区（high-risk clinical target area,HR-CTV）剂量为6 Gy/次,1次/周,共5次。68例患者采用随机数表法分为两组,其中模板组35例采用3D打印微创导向模板辅助置入宫腔管并植入插植针;自由插植组33例徒手进行宫腔管的置入及插植针的植入。所有患者均于CT引导下调整宫腔管、插植针位置及深度,将最终CT图像传入后装治疗计划系统,勾画靶区及危及器官,制定治疗计划,实施治疗。结果 共制定340次后装放疗计划,其中模板组175次、自由插植组165次。模板组较自由插植组的HR-CTV的D₉₀（包绕90%靶区体积的剂量）、中危临床靶区（intermediate-risk clinical target volume,IR-CTV）的D₉₀均明显增高（t=3.63、2.45,P<0.05）,膀胱、直肠及乙状结肠的D_{2 cm³}均显著降低（t=-2.81、-2.54、-2.33,P<0.05）。同时,模板组每次后装治疗平均扫描CT次数为（1.78±0.53）次,每次治疗从宫腔管及插植针植入至调整达满意位置的平均消耗时间为（11.35±3.98）min,每次治疗使用插植针的针数平均为（5.21±1.37）枚。而自由插植组分别为（3.56±0.88）次,（30.67±5.83）min,（7.48±2.79）枚,两组比较差异均具有统计学意义（t=-2.26、-4.53、-3.21,P<0.05）。结论 对于偏心性或巨大肿块的局部晚期宫颈癌患者,腔内联合组织间插植治疗应用3D打印微创导向模板剂量学优势明显,操作简便,用时短。     

形变配准在宫颈癌近距离放疗分次间剂量评估中的可行性研究

目的:比较近距离放疗分次间靶区和正常组织在形变配准(DIR)和简单累加剂量体积直方图(DVH)情况下,累积剂量的剂量学差异,分析在宫颈癌三维近距离放疗计划中,形变配准技术应用于靶区和正常组织剂量评估的可行性。方法:回顾性选取13例宫颈癌近距离放疗病例,每个病例均进行了4次CT定位的近距离放疗。对每个病例的4次CT进行形...     

全中枢神经系统肿瘤放疗技术的剂量学研究

目的 以三维适形放疗技术为参照,探讨中枢神经系统肿瘤简单调强(sIMRT)放疗技术的剂量学特性。方法 选取5名已行全脑全脊髓放疗患者,为每位患者设计3D-CRT计划、3野和5野sIMRT计划。利用剂量分布和剂量体积直方图(DVH),评价不同照射技术的靶区和正常器官的照射剂量、靶区剂量均匀性(HI),通过总的机器跳数(MU)间接比较不同照射技术的治疗时间。结果 3D-CRT在射野衔接处只有处方剂量的70%。计划靶区后缘的正常组织接受的剂量达到处方剂量的140%。3野和5野sIMRT计划的靶区剂量均匀性分别为0.09±0.01和0.08±0.01,优于3D-CRT计划的0.18±0.02 (t=7.80、7.65,P<0.05);心脏V₁₀分别为(8.4±1.9)%和(8.4±2.0)%,低于3D-CRT计划的(36.0±6.0)%(t=13.3、13,0,P<0.05);甲状腺V₂₀分别为(12.4±1.5)%和(12.4±1.6)%,低于3D-CRT计划的(69.4±5.7)%(t=26.3、26.4,P<0.05);喉V₂₀分别为(17.2±1.2)%和(17.9±1.5)%,低于3D-CRT计划的(89.4±7.0)%(t=25.5、26.5,P<0.05);靶区后缘正常组织V₃₀分别为(4.4±1.4)%,(4.9±1.9)%,低于3D-CRT计划的(31.9±6.1)%(t=8.5、10.1,P<0.05);平均机器跳数(MU)分别为1100±106和1160±129,高于3D-CRT计划的640±78。结论 3野和5野sIMRT计划在剂量分布、危及器官(OAR)保护、靶区剂量均匀性等方面均好于3D-CRT计划。     

容积旋转调强与固定野调强在晚期宫颈癌放疗的剂量学比较及疗效观察

目的 比较容积旋转调强（RapidArc）和固定野调强（IMRT）技术在宫颈癌根治性放疗的剂量学参数、急性不良反应发生率及疗效。方法 回顾性分析43例局部晚期（II_b~IV）宫颈癌患者,其中22例行容积旋转调强放疗,21例行固定野调强放疗,处方剂量50.4 Gy/28次,比较两组靶区剂量适形度、均匀性、靶区及危及器官的剂量、机器跳数及治疗时间;对比两组患者治疗期间的急性肠道及膀胱反应发生率;对比两组患者的完全缓解率和有效率。结果 与IMRT计划相比,RapidArc计划的靶区适形性指数CI略好,但差异无统计学意义（P > 0.05）;两组计划的靶区均匀性指数HI比较,差异无统计学意义（P > 0.05）。RapidArc计划中膀胱的V₄₀、V₅₀以及直肠的V₃₀、V₄₀、V₅₀均低于IMRT计划（t=-2.386、-2.397、-5.525、-2.883、-2.686,P < 0.05）,RapidArc计划中股骨头的平均剂量低于IMRT计划（t=-2.395,P < 0.05）。RapidArc较IMRT平均MU减少了53.15%,治疗所需平均时间缩短了62.14%。两组患者肠道、膀胱急性反应发生率相近。两组患者完全缓解率和有效率相近。结论 晚期宫颈癌根治性放疗中,采用RapidArc技术可以降低危及器官受量,缩短患者的治疗时间。     

直肠癌术前放疗中三维适形放疗与调强适形放疗的剂量学比较分析

目的 比较三维适形放疗(3D-CRT)与5野、7野调强适形放疗(IMRT)的剂量分布,以探讨IMRT对直肠癌术前放疗的价值。方法 对10例术前新辅助放化疗直肠癌患者,分别设计3D- CRT、5野IMRT、7野IMRT计划,应用剂量体积直方图(DVH),比较3种治疗计划的靶区适形度指数(CI)、不均匀性指数(HI)和正常器官受量。结果 适形度指数(CI)7野IMRT计划＞5野IMRT＞3D- CRT,不均匀性指数(HI)5野IMRT计划＞7野IMRT＞3D- CRT。5野、7野IMRT计划比3D- CRT均可以减少高剂量照射小肠、膀胱、股骨头体积,7野IMRT计划比5野可以减少高剂量照射的骨髓和膀胱的体积。结论 直肠癌术前放疗中IMRT计划在靶区剂量适形度方面均优于3D- CRT计划,对正常组织的保护也存在明显的优势。7野IMRT计划较5野IMRT计划技术有更好的剂量适形度与剂量均匀性。     

Effect of brachytherapy technique and patient characteristics on cervical cancer implant dosimetry

Our purpose was to evaluate the relationship between brachytherapy technique and patient characteristics on dose to organs-at-risk (OARs) in patients undergoing high dose rate (HDR) brachytherapy for cervical cancer. From 1998 to 2008, 31 patients with cervical cancer with full dosimetric data were identified who received definitive external-beam radiation and HDR brachytherapy with tandem and ovoid applicators. Doses were recorded at point A, the International Commission on Radiation Units and Measurements (ICRU)-38 rectal point, the ICRU-38 bladder point, the vaginal surface, and the pelvic sidewall. Generalized estimating equations were used to determine the significance of changes in OAR to point A dose ratios with differences in brachytherapy technique or patient characteristics. Patients underwent a median of 5 brachytherapy procedures (range, 3 to 5), with a total of 179 procedures for 31 patients. For all brachytherapy treatments, the average ratios between the doses for the rectal, bladder, vaginal surface, and pelvic sidewall reference points to those at point A were 0.49, 0.59, 1.15, and 0.17, respectively. In general, decreased OAR dose was associated with a lower stage, younger age, increased ovoid size, increased tandem length, and earlier implant number. Increased tandem curvature significantly increased bladder dose and decreased rectal dose. Intravenous anesthesia usage was not correlated with improved dosimetry. This study allowed identification of patient and procedure characteristics influencing OAR dosing. Although the advent of 3-dimensional (3D) image-guided brachytherapy will bring new advances in treatment optimization, the actual technique involved at the time of the brachytherapy implant procedure will remain important.     

敷贴治疗寻常型银屑病的疗效分析

目的：探讨90Sr-90Y敷贴与口服复方氨肽素片治疗寻常型局限性银屑病的疗效及安全性。方法将108例寻常型局限性银屑病患者按治疗意愿分为敷贴治疗组和药物治疗组。敷贴治疗组：按常规敷贴治疗,每个疗程治疗5次,隔日1次,每疗程总吸收剂量为30~50 Gy;药物治疗组：口服复方氨肽素片,1次口服5片,每日3次,连续治疗9周为1个疗程。结果90Sr-90Y敷贴治疗组痊愈患者为32例,显效为19例,总有效率为87.93%;复方氨肽素治疗组痊愈患者为16例,显效为14例,总有效率为60.00%。χ2检验得出两组总有效率的差异有统计学意义（χ2=11.17,P＜0.05）。不良反应比较,两组不良反应发生率分别为17.24%和32.00%,差异无统计学意义（χ2=3.20,P＞0.05）。复发情况比较,两组复发率分别为21.88%和56.25%,差异有统计学意义（χ2=5.67,P＜0.05）。结论90Sr-90Y敷贴治疗方法简单、无痛苦、疗效高、复发率低,患者不用长期服药,可以作为一种治疗寻常型局限性银屑病的有效方法。     

Proficiency-based cervical cancer brachytherapy training

PurposeAlthough brachytherapy increases the local control rate for cervical cancer, there has been a progressive decline in its use. Furthermore, the training among residency programs for gynecologic brachytherapy varies considerably, with some residents receiving little to no training. This trend is especially concerning given the association between poor applicator placement and decline in local control. Considering the success of proficiency-based training in other procedural specialties, we developed and implemented a proficiency-based cervical brachytherapy training curriculum for our residents.Methods and MaterialsEach resident placed tandem and ovoid applicators with attending guidance and again alone 2 weeks later using a pelvic model that was modified to allow for cervical brachytherapy. Plain films were taken of the pelvic model, and applicator placement quality was evaluated. Other evaluated metrics included retention of key procedural details, the time taken for each procedure and presession and postsession surveys to assess confidence.ResultsDuring the initial session, residents on average met 4.5 of 5 placement criteria, which improved to 5 the second session. On average, residents were able to remember 7.6 of the 8 key procedural steps. Execution time decreased by an average of 10.5%. Resident confidence with the procedure improved dramatically, from 2.6 to 4.6 of 5. Residents who had previously never performed a tandem and ovoid procedure showed greater improvements in these criteria than those who had. All residents strongly agreed that the training was helpful and wanted to participate again the following year.ConclusionsResidents participating in this simulation training had measurable improvements in the time to perform the procedure, applicator placement quality, and confidence. This curriculum is easy to implement and is of great value for training residents, and would be particularly beneficial in programs with low volume of cervical brachytherapy cases. Simulation programs could also be created for other technically challenging radiation oncology procedures.     

Impact of marital status on receipt of brachytherapy and survival outcomes in locally advanced cervical cancer

PurposeMarriage has been associated with enhanced survival among cancer patients, but conflicting correlations have been suggested in cervical cancer. We assessed the impact of marital status on receipt of brachytherapy and survival in women with locally advanced cervical cancer.Methods and MaterialsThree thousand, eight hundred and twelve patients with Stage IB2–IVA cervical cancer diagnosed from 2006 to 2015 treated with external beam radiotherapy were identified from the California Cancer Registry. Chi-square tests were used to compare patient characteristics by marital status and boost type. The association of marital status with brachytherapy (BT) receipt was assessed using multiple logistic regression. Fine and Gray competing risks and Cox proportional hazards regressions were used to estimate cervical cancer–specific survival (CCSS) and overall survival (OS), respectively.ResultsMost women were unmarried (58.8%). Half (50.4%) received BT, while 33.1% received no boost; most (86.3%) received chemotherapy. Unmarried women had similar odds of receiving BT as married women (OR = 1.07, 95% CI: 0.90-1.28, p = 0.4370) but were less likely to receive chemotherapy (84.3% vs. 89.1%, p < 0.0001). Singlehood was significantly associated with worse CCSS (subdistribution hazard ratio = 1.21, 95% CI: 1.03-1.42, p < 0.0174) and OS (hazard ratio = 1.18, 95% CI: 1.03-1.36, p < 0.0153). Not receiving a radiation boost was also significantly associated with worse CCSS (subdistribution hazard ratio = 1.21, 95% CI: 1.02-1.43, p = 0.0317) and OS (hazard ratio = 1.21, 95% CI: 1.05-1.40, p = 0.0100).ConclusionsThere were no differences in BT receipt in married vs. unmarried patients. However, unmarried patients had worse CCSS and OS and were less likely to receive chemotherapy. Interventions targeting social factors are needed to improve outcomes in this vulnerable population.     

Dosimetric effect of external beam planning preceding combined high-dose-rate brachytherapy of the prostate

Purpose

The sequencing of external beam radiotherapy (EBRT) and a high-dose-rate brachytherapy (HDRB) boost is often interchangeable in clinical practice. When given before EBRT, HDRB could induce volume alterations in the prostate, which may have significant implications for EBRT dosimetry. We aimed to assess the influence of HDRB on prostate volume and, hence, prostate dosing via subsequent EBRT.

Methods and Materials

Fifteen men had both pre- and post-HDRB CT performed followed by EBRT. After deidentification, the clinical target volume (CTV) was defined on each CT by a single-blinded observer. Volumes were compared for the pre- and post-HDRB scans in each patient. Radiotherapy planning was performed using the prebrachytherapy volumes aiming for the planning target volume (PTV) to be covered by 43.7 Gy. After soft-tissue coregistration, this plan was also applied to the postbrachytherapy volumes.

Results

Median volume increase was 35.4% for the CTV after HDRB. No patient experienced a decrease in CTV volume (range, 0-79% volume increase; p-value < 0.001). Median volume increase was 26.1% for the PTVs, with no volume decrease observed (range, 8-56%; p < 0.001). PTV proportion achieving dose target (V43.7 Gy) decreased by median of 7% (range, 0-21.5%; p = 0.004). The minimum dose to the PTV (D₁₀₀%) decreased by a median of 6 Gy (range, 0.5-16 Gy; p < 0.001).

Conclusions

Insertion of HDRB catheters exerts substantial acute volumetric distortion on the prostate. EBRT planning performed on the basis of pre-HDRB imaging only inherently risks underdosing tumor. Planning adjustments based on repeat CT, or dedicated post-HDBT planning, is warranted for men managed with HDRB before EBRT.     

Predicting which patients may benefit from the hybrid intracavitary+interstitial needle (IC/IS) applicator for advanced cervical cancer: A dosimetric comparison and toxicity benefit analysis

PurposeThe purpose of this study is to compare the predicted rate of local control and bladder and rectum toxicity rates for image-guided adaptive brachytherapy plans using a tandem and ovoid (T/O) applicator versus using a simulated hybrid intracavitary/interstitial tandem and ring applicator with needles (T/R + N) for patients with locally advanced cervical cancer (LACC).Methods and MaterialsPatients with ≥ FIGO Stage IIB locally advanced cervical cancer treated with T/O from a single institution were included. Simulated treatment plans were created with a T/R + N applicator for the best high-risk clinical target volume (CTV) coverage and minimal dose to organs at risk. Three-year local control rate was estimated using published dose-volume effect relationships. Next, the high-risk CTV EQD2 D90 of T/R + N plans were calculated, and bladder and rectum toxicity rates were estimated. Analysis was performed in subpatient groups defined based on tumor volume and ratio of maximal and minimal tumor radii (RR) that reflects tumor shape asymmetry.ResultsImprovements in predicted local control rate for the T/R + N were 0.8, 4.1, 1.6, and 3.9% for groups with tumor volume <35 cc, ≥35 cc, RR < 2.0, and ≥2.0, respectively, with the latter three being statistically significant. Predicted reductions in Grade 2–4 toxicity rates of bladder and rectum were significant in all groups except bladder toxicity in tumor volume <35 cc, when T/R + N plans were normalized to the same CTV coverage as the T/O plans. Comparing unnormalized T/R + N plans and T/O plans, predicted toxicity reductions were significant in all groups except rectum toxicity in RR ≥ 2.0. Predicted reduction of toxicity rate was larger for patients with large tumor or large tumor RR, although some reductions were relatively small.ConclusionsCases with large tumor (volume ≥35 cc) or large tumor asymmetry (RR ≥ 2.0) would probably benefit more from the use of hybrid applicators.     

Quantitative CT assessment of a novel direction-modulated brachytherapy tandem applicator

PurposeThe purpose of this study was to quantitatively assess the CT metal-induced artifacts from a novel direction-modulated brachytherapy (DMBT) tandem applicator prototype, recently designed for cervical cancer treatments.Methods and materialsA water-based pelvic phantom was constructed for CT scanning. The DMBT applicator was imaged using our institutional protocol, one with higher kVp and mAs settings, and repetition of these protocols using 3-mm slices. A conventional stainless steel applicator was also scanned. In addition to the standard reconstructed images, applicator images were reconstructed using a commercial metal artifact-reduction (MAR) algorithm and an in-house–developed research algorithm. Subsequently, image quality and artifact severity were evaluated.ResultsArtifact severity, measured in terms of SDs in CT numbers, decreased asymptotically to background water levels with the distance away from the applicator. Artifact-reduction algorithms lead to significant and visible improvements in image quality, with >50% and >20% decrease in artifact severity achieved at a 10-mm distance for the DMBT and stainless steel applicators, respectively. Differences in artifact severity were minimal between the four imaging protocols. DMBT dimensions were the same on images with and without the commercial MAR algorithm, within <1 mm of the theoretical value. Both the commercial and in-house algorithms restored the CT numbers outside the applicator, albeit a better performance was achieved by the in-house algorithm.ConclusionsThe artifacts produced by both applicators were minimized with the use of MAR algorithms. Adoption of the DMBT and stainless steel applicators for CT-guided brachytherapy is anticipated as MAR algorithms are widely available on CT scanners.     

Reduction of computed tomography metal artifacts due to the Fletcher-Suit applicator in gynecology patients receiving intracavitary brachytherapy

PURPOSE: To evaluate a method of reducing computed tomography (CT) metal artifacts due to the Fletcher-Suit applicator. METHODS AND MATERIALS: We apply a projection-interpolation algorithm to CT images containing artifacts from the brachytherapy applicator. Regions of projection data containing the applicator are interpolated, removing the metal from the projections. A new image is then reconstructed, and a pixel-by-pixel correction factor applied to the original image to reduce the severity of metal artifacts. This technique is applied to phantom and patient image data. RESULTS: Qualitative and quantitative comparisons of images produced before and after projection-interpolation show a significant reduction in metal artifacts. In patient images containing the tandem alone, this method almost completely eliminated the artifact. In slices containing both tandem and colpostats, the algorithm reduced artifacts but did not completely eliminate them. CONCLUSIONS: The projection-interpolation method can be used to reduce the severity of metal artifacts caused by the Fletcher-Suit applicator.