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。     

IMRT to Escalate the Dose to the Prostate while Treating the Pelvic Nodes

Background and Purpose: To assess and quantify the benefit of introducing intensity–modulated radiotherapy (IMRT) over conventional approaches to cover the pelvic nodes while escalating the dose to the prostate gland.Material and Methods: The pelvic lymphatics were planned to receive 50 Gy at 2 Gy per fraction by four–field box (4FB) technique and standard field blocks drawn on digitally reconstructed radiographs (DRR), 4FB with field blocks according to the position of pelvic nodes as contoured on serial planning CT slices, or IMRT. The lateral fields included three different variations of field blocks to assess the role of various degrees of rectal shielding. The boost consisted in 26 Gy in 13 fractions delivered via six–field three–dimensional conformal radiotherapy (3DCRT) or IMRT. By the combination of a pelvic treatment and boost, several plans were obtained for each patient, all normalized to be isoeffective with regard to prostate–planning target volume (PTV–P) coverage. Plans were compared with respect to dose–volume histogram (DVH) of pelvic nodes/seminal vesicles–PTV (PTV–PN/SV), rectum, bladder and intestinal cavity. Reported are the results obtained in eight patients.Results: Pelvic IMRT with a conformal boost provided superior sparing of both bladder and rectum over any of the 4FB plans with the same boost. For the rectum the advantage was around 10% at V70 and even larger for lower doses. Coverage of the pelvic nodes was adequate with initial IMRT with about 98% of the volume receiving 100% of the prescribed dose. An IMRT boost provided a gain in rectal sparing as compared to a conformal boost. However, the benefit was always greater with pelvic IMRT followed by a conformal boost as compared to 4FB with IMRT boost. Finally, the effect of utilizing an IMRT boost with initial pelvic IMRT was greater for the bladder than for the rectum (at V70, about 9% and 3% for the bladder and rectum, respectively).Conclusion: IMRT to pelvic nodes with a conformal boost allows dose escalation to the prostate while respecting current dose objectives in the majority of patients and it is dosimetrically superior to 4FB. An IMRT boost should be considered for patients who fail to meet bladder dose objectives.     

A comparison of conventional, conformal and intensity-modulated coplanar radiotherapy plans for posterior fossa treatment

Radiotherapy of the posterior fossa for medulloblastoma treatment can induce ototoxicity, especially when combined with cisplatin chemotherapy. Sensorineural hearing loss can be severe enough to cause permanent disability, which may compromise cognitive development in paediatric patients. This study evaluates the sparing of the cochlea in conventional radiotherapy, three-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT). CT scans of three patients were used to plan posterior fossa radiotherapy using coplanar beam arrangements. The posterior fossa and the cochlea were contoured as well as other organs-at-risk (non-posterior fossa brain, lenses, optic nerves, pituitary and cervical spinal cord). Three treatment plans were compared: conventional two-dimensional treatment (parallel-opposed lateral pair); 3D-CRT (two wedged posterior oblique fields); and a four-field coplanar IMRT plan. 3D-CRT and IMRT reduced cochlear doses to less than 70% of the mean target dose. These plans also reduced dose to the non-posterior fossa brain and cervical spinal cord. IMRT showed no advantage over 3D-CRT in sparing the optic nerves and lenses, compared with 3D-CRT. Normal tissue doses were higher in both conformal techniques than in the IMRT plans. Conformal techniques reduced the dose to the cochlea, non-posterior fossa brain and cervical spinal cord. The small size and proximity to the planning target volume (PTV) of the cochlea limited the effectiveness of the IMRT plan. Coplanar 3D-CRT was judged superior to coplanar IMRT, particularly in children, because it achieved adequate sparing of the cochlea and anterior cranial structures, such as the lenses and optic nerves, without compromising the dose to the posterior fossa.     

Physical and clinical implications of radiotherapy treatment of prostate cancer using a full bladder protocol

Purpose

To assess the dosimetric and clinical implication when applying the full bladder protocol for the treatment of the localized prostate cancer (PCA).

Patients and Methods

A total of 26 consecutive patients were selected for the present study. Patients underwent two series of CT scans: the day of the simulation and after 40 Gy. Each series consisted of two consecutive scans: (1) full bladder (FB) and (2) empty bladder (EB). The contouring of clinical target volumes (CTVs) and organs at risk (OAR) were compared to evaluate organ motion. Treatment plans were compared by dose distribution and dose?Cvolume histograms (DVH).

Results

CTV shifts were negligible in the laterolateral and superior?Cinferior directions (the maximum shift was 1.85 mm). Larger shifts were recorded in the anterior?Cposterior direction (95% CI, 0.83?C4.41 mm). From the dosimetric point of view, shifts are negligible: the minimum dose to the CTV was 98.5% (median; 95%CI, 95?C99%). The potential advantage for GU toxicity in applying the FB treatment protocol was measured: the ratio between full and empty bladder dose?Cvolume points (selected from our protocol) is below 0.61, excluding the higher dose region where DVHs converge.

Conclusion

Having a FB during radiotherapy does not affect treatment effectiveness, on the contrary it helps achieve a more favorable DVH and lower GU toxicities.     

Intensity-modulated radiotherapy for a prostate patient with a metal prosthesis

When treating prostate patients having a metallic prosthesis with radiation, a 3D conformal radiotherapy (3DCRT) treatment plan is commonly created using only those fields that avoid the prosthesis in the beam’s-eye view (BEV). With a limited number of portals, the resulting plan may compromise the dose sparing of the rectum and bladder. In this work, we investigate the feasibility of using intensity-modulated radiotherapy (IMRT) to treat prostate patients having a metallic prosthesis. Three patients, each with a single metallic prosthesis, who were previously treated at the University of Chicago Medical Center for prostate cancer, were selected for this study. Clinical target volumes (CTV = prostate + seminal vesicles), bladder, and rectum volumes were identified on CT slices. Planning target volumes (PTV) were generated in 3D by a 1-cm expansion of the CTVs. For these comparative studies, treatment plans were generated from CT data using 3DCRT and IMRT treatment planning systems. The IMRT plans used 9 equally-spaced 6-MV coplanar fields, with each field avoiding the prosthesis. The 3DCRT plans used 5 coplanar 18-MV fields, with each field avoiding the prosthesis. A 1-cm margin around the PTV was used for the blocks. Each of the 9-field IMRT plans spared the bladder and rectum better than the corresponding 3DCRT plan. In the IMRT, plans, a bladder volume receiving 80% or greater dose decreased by 20–77 cc, and a volume rectal volume receiving 80% or greater dose decreased by 24–40 cc. One negative feature of the IMRT plans was the homogeneity across the target, which ranged from 95% to 115%.     

Postoperative Intensity Modulated Radiation Therapy in High Risk Prostate Cancer: A Dosimetric Comparison

The aim of this study was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal technique (3D-CRT), with respect to target coverage and irradiation of organs at risk for high dose postoperative radiotherapy (PORT) of the prostate fossa. 3D-CRT and IMRT treatment plans were compared with respect to dose to the rectum and bladder. The dosimetric comparison was carried out in 15 patients considering 2 different scenarios: (1) exclusive prostate fossa irradiation, and (2) pelvic node irradiation followed by a boost on the prostate fossa. In scenario (1), a 3D-CRT plan (box technique) and an IMRT plan were calculated and compared for each patient. In scenario (2), 3 treatment plans were calculated and compared for each patient: (a) 3D-CRT box technique for both pelvic (prophylactic nodal irradiation) and prostate fossa irradiation (3D-CRT only); (b) 3D-CRT box technique for pelvic irradiation followed by an IMRT boost to the prostatic fossa (hybrid 3D-CRT and IMRT); and (c) IMRT for both pelvic and prostate fossa irradiation (IMRT only). For exclusive prostate fossa irradiation, IMRT significantly reduced the dose to the rectum (lower Dmean, V50%, V75%, V90%, V100%, EUD, and NTCP) and the bladder (lower Dmean, V50%, V90%, EUD and NTCP). When prophylactic irradiation of the pelvis was also considered, plan C (IMRT only) performed better than plan B (hybrid 3D-CRT and IMRT) as respect to both rectum and bladder irradiation (reduction of Dmean, V50%, V75%, V90%, equivalent uniform dose [EUD], and normal tissue complication probability [NTCP]). Plan (b) (hybrid 3D-CRT and IMRT) performed better than plan (a) (3D-CRT only) with respect to dose to the rectum (lower Dmean, V75%, V90%, V100%, EUD, and NTCP) and the bladder (Dmean, EUD, and NTCP). Postoperative IMRT in prostate cancer significantly reduces rectum and bladder irradiation compared with 3D-CRT.     

非小细胞肺癌精确放疗中三种CT扫描方法的研究

目的 比较自主呼吸控制(ABC)、自由呼吸(FB)状态下慢速CT扫描(SS)和常规轴位扫描在周围型非小细胞肺癌(NSCLC)精确放疗中减小放射性肺损伤方面的作用差异。方法 10例周围型NSCLC患者在适形放疗定位时分别采集3种CT图像:1FB时常规轴位扫描;2ABC螺旋CT快速扫描;3FB时慢速CT扫描。将3套图像传输至计划系统,分别制定3个适形放疗计划,比较3个计划的大体肿瘤靶区(GTV)、临床靶区(CTV)、计划靶区(PTV)、受照剂量>20 Gy的正常肺组织占全肺体积的百分比(V₂₀)及全肺平均受照剂量(D_mean)。结果 3个计划的GTV、CTV体积以慢速扫描似乎最大,ABC计划似乎最小,但差异无统计学意义(F=1.513,P=0.238;F=1.376,P=0.270);FB常规轴位计划的PTV体积最大,且分别与另2个计划间差异有统计学意义(F=26.148,P=0.000);V₂₀、D_mean在FB常规轴位计划均最大,且FB计划和另2个计划间差异有统计学意义(F=7.623,P=0.002;F=18.217,P=0.000)。结论 相对于FB状态,使用ABC或慢速CT扫描可有效减少周围型NSCLC精确放疗中正常组织的受照体积和剂量,减小放射性肺损伤的发生率。     

Treatment of pancreatic cancer tumors with intensity-modulated radiation therapy (IMRT) using the volume at risk approach (VARA): employing dose-volume histogram (DVH) and normal tissue complication probability (NTCP) to evaluate small bowel toxicity.

The emergent use of a combined modality approach (chemotherapy and radiation) in pancreatic cancer is associated with increased gastrointestinal toxicity. Intensity-modulated radiation therapy (IMRT) has the potential to deliver adequate dose to the tumor volume while decreasing the dose to critical structures such as the small bowel. We evaluated the influence of IMRT with inverse treatment planning on the dose-volume histograms (DVHs) of normal tissue compared to standard 3-dimensional conformal radiation treatment (3D-CRT) in patients with pancreatic cancer. Between July 1999 and May 2001, 10 randomly selected patients with adenocarcinoma of the pancreatic head were planned simultaneously with 3D-CRT and inverse-planned IMRT using the volume at risk approach (VaRA) and compared for various dosimetric parameters. DVH and normal tissue complication probability (NTCP) were calculated using IMRT and 3D-CRT plans. The aim of the treatment plan was to deliver 61.2 Gy to the gross tumor volume (GTV) and 45 Gy to the clinical treatment volume (CTV) while maintaining critical normal tissues to below specified tolerances. IMRT plans were more conformal than 3D-CRT plans. The average dose delivered to one third of the small bowel was lower with the IMRT plan compared to 3D-CRT. The IMRT plan resulted in one third of the small bowel receiving 30.2+/-12.9 Gy vs. 38.5+/-14.2 Gy with 3D-CRT (p = 0.006). The median volume of small bowel that received greater than either 50 or 60 Gy was reduced with IMRT. The median volume of small bowel exceeding 50 Gy was 19.2+/-11.2% (range 3% to 45%) compared to 31.4+/-21.3 (range 7% to 70%) for 3D-CRT (p = 0.048). The median volume of small bowel that received greater than 60 Gy was 12.5+/-4.8% for IMRT compared to 19.8+/-18.6% for 3D-CRT (p = 0.034). The VaRA approach employing IMRT techniques resulted in a lower dose per volume of small bowel that exceeded 60 Gy. We used the Lyman-Kutcher models to compare the probability of small bowel injury employing IMRT compared to 3D-CRT. The BIOPLAN model predicted a small bowel complication probability of 9.3+/-6% with IMRT compared to 24.4+/-18.9% with 3D-CRT delivery of dose (p = 0.021). IMRT with an inverse treatment plan has the potential to significantly improve radiation therapy of pancreatic cancers by reducing normal tissue dose, and simultaneously allow escalation of dose to further enhance locoregional control.     

Pelvic Ewing sarcomas

Purpose

The goal of the present work was to assess the potential advantage of intensity-modulated radiotherapy (IMRT) over three-dimensional conformal radiotherapy (3D-CRT) planning in pelvic Ewing’s sarcoma.

Patients and methods

A total of 8 patients with Ewing sarcoma of the pelvis undergoing radiotherapy were analyzed. Plans for 3D-CRT and IMRT were calculated for each patient. Dose coverage of the planning target volume (PTV), conformity and homogeneity indices, as well as further parameters were evaluated.

Results

The average dose coverage values for PTV were comparable in 3D-CRT and IMRT plans. Both techniques had a PTV coverage of V₉₅ >?98?% in all patients. Whereas the IMRT plans achieved a higher conformity index compared to the 3D-CRT plans (conformity index 0.79?±?0.12 vs. 0.54?±?0.19, p?=?0.012), the dose distribution across the target volumes was less homogeneous with IMRT planning than with 3D-CRT planning. This difference was statistically significant (homogeneity index 0.11?±?0.03 vs. 0.07?±?0.0, p?=?0.035). For the bowel, D_mean and D_1%, as well as V₂ to V₆₀ were reduced in IMRT plans. For the bladder and the rectum, there was no significant difference in D_mean. However, the percentages of volumes receiving at least doses of 30, 40, 45, and 50 Gy (V₃₀ to V₅₀) were lower for the rectum in IMRT plans. The volume of normal tissue receiving at least 2 Gy (V₂) was significantly higher in IMRT plans compared with 3D-CRT, whereas at high dose levels (V₃₀) it was significantly lower.

Conclusion

Compared to 3D-CRT, IMRT showed significantly better results regarding dose conformity (p?=?0.012) and bowel sparing at dose levels above 30 Gy (p?=?0.012). Thus, dose escalation in the radiotherapy of pelvic Ewing’s sarcoma can be more easily achieved using IMRT.     

基于食管癌放射治疗计划的剂量学研究

目的应用三维治疗计划系统（3D—TPS）比较研究食管癌的不同照射方法，评价常规三野等中心照射（RT）、三维适形（3D～CRT）、调强适形放射治疗（IMRT）在靶区剂量及正常组织保护方面的不同。方法采用三维治疗计划系统对12例经病理证实的中下段食管癌的患者CT定位图像分别设计3种放射治疗计划，分别为RT，3 D—CRT，IMRT，计划的处方剂量均为50 Gy，通过治疗计划及剂量体积直方图（DVH）比较靶区及危及器官剂量的差异。结果RT，3 D—CRT，IMRT的95％计划靶体积（PTV）及95％大体肿瘤体积（GTV）的剂量有统计学意义，3 D—CRT和IMRT优于RT；3种计划的靶区适形度指数、PTV剂量变异度指数、处方剂量覆盖GTV百分比均以IMRT计划为最好，3D—CRT、IMRT减少了双肺受照20 Gu体积百分比（V20），均有统计学意义；3种计划的脊髓最大所受剂量、心脏1／3体积的所受剂量均在可耐受的范围内，IMRT为最小，P〉0．05。结论3 D—CRT、IMRT在靶区适形度和靶区剂量上均优于RT，能获得均匀的剂量分布，且能降低周围敏感器官的所受剂量，正常组织所受剂量均能在耐受范围内。     

3D-Conformal Versus Intensity-Modulated Postoperative Radiotherapy of Vaginal Vault: A Dosimetric Comparison

We evaluated a step-and-shoot IMRT plan in the postoperative irradiation of the vaginal vault compared with equispaced beam arrangements (3–5) 3D-radiotherapy (RT) optimized plans. Twelve patients were included in this analysis. Four plans for each patient were compared in terms of dose-volume histograms, homogeneity index (HI), and conformity index (CI): (1) 3 equispaced beam arrangement 3D-RT; (2) 4 equispaced beam arrangement 3D-RT; (3) 5 equispaced beam arrangement 3D-RT; (4) step-and-shoot IMRT technique. CI showed a good discrimination between the four plans. The mean scores of CI were 0.58 (range: 0.38–0.67) for the 3F-CRT plan, 0.58 (range: 0.41–0.66) for 4F-CRT, 0.62 (range: 0.43–0.68) for 5F-CRT and 0.69 (range: 0.58–0.78) for the IMRT plan. A significant improvement of the conformity was reached by the IMRT plan (p < 0.001 for all comparisons). As expected, the increment of 3D-CRT fields was associated with an improvement of target dose conformity and homogeneity; on the contrary, in the IMRT plans, a better conformity was associated to a worse target dose homogeneity. A significant reduction in terms of D_mean, V90%, V95%, V100% was recorded for rectal and bladder irradiation with the IMRT plan. Surprisingly, IMRT supplied a significant dose reduction also for rectum and bladder V30% and V50%. A significant dosimetric advantage of IMRT over 3D-RT in the adjuvant treatment of vaginal vault alone in terms of treatment conformity and rectum and bladder sparing is shown.     

Anatomic Variations Due to Radical Prostatectomy

BACKGROUND AND PURPOSE: A quantitative estimate of the impact of prostatectomy on pelvic anatomy is unavailable, even if it would be an important prerequisite for a precise definition of clinical target volume (CTV) in post-prostatectomy radiotherapy. The purpose of this study was to investigate the impact of prostatectomy on the definition of CTV, on the position of bladder and rectum and their implications for three-dimensional conformal radiotherapy (3-D CRT). PATIENTS AND METHODS: Six patients eligible for radical retropubic prostatectomy were considered. Each patient underwent a planning CT between 1 week and 1 month before surgery (CTpre), and then CT was repeated in the same positioning 1-2 months after surgery (CTpost). For each patient the CT(pre/post) scans were matched; rectum, bladder and CTV were contoured on both CT scans for each patient by one observer. Two different CTVs were contoured: CTV1: prostate + seminal vesicles in CTpre; prostate + seminal vesicles surgical bed in CTpost; CTV2: prostate in CTpre; prostate surgical bed in CT(post). After image registration, the contours of rectum, bladder and CTV1/2 drawn on CTpost were transferred on CTpre. The corresponding planning target volumes (PTVs) were generated, and for each PTV, a conformal four field technique using 18-MV X-rays was planned. The volumes of CTV1, CTV2, PTV1, PTV2, rectum and bladder pre- and post-surgery were compared. Differences in 3-D position of these structures before and after surgery were analyzed by beam's eye view (BEV) images. Pre- and post-surgery dose-volume histograms (DVHs) of rectum and bladder were compared together with the fraction of rectum/bladder receiving at least 95% of the ICRU dose (V95), the treated volume (TV, body included in the 95% isodose) and the irradiated volume (IV, body included in the 50% isodose). RESULTS: For both CTV1 and CTV2, the volumes were significantly reduced after prostatectomy (average reduction around 30 cm3 for both; range 0-60 cm3). This reduction was mainly due to a more caudal definition of the cranial edge of CTV after prostatectomy (average difference for CTV2: 1.5 cm; range 0-2.5 cm). Concerning the bladder, a systematic posterior shift of the bladder base (average: 1.5 cm) was found and was correlated with a significant reduction of V95 for bladder (around 10 cm3; p = 0.03). V95 of the rectum, TV and IV also resulted to be significantly lower after surgery. The average reduction of V95 for the rectum was relatively small (2.5 cm3 of rectal wall). CONCLUSION: The impact of prostatectomy on CTV definition is high. A significant reduction of CTV, PTV, TV and IV may be expected after surgery with a consequent reduction of the portions of rectum/bladder irradiated with adjuvant radiotherapy.     

胃癌术后三维适形放疗及调强放疗靶区勾画研究进展

临床靶区的准确勾画是实施胃癌适形/调强放射治疗（3D-CRT/IMRT）的关键步骤。以往指南曾对胃癌术后2D放疗的照射范围进行了推荐,目前尚缺乏3D-CRT/IMRT时代胃癌术后放疗的靶区勾画共识。本文拟对胃癌术后放射治疗个体化临床靶区勾画的最新研究进展及争议进行介绍。胃癌术后3D-CRT/IMRT放疗靶区有待进一步优化。     

A Pelvic Phantom for Modeling Internal Organ Motions

A pelvic phantom was developed for use in testing image-guided radiation therapy (IGRT) and adaptive applications in radiation therapy (ART) with simulating the anterior-posterior internal organ motions during prostate radiotherapy. Measurements could be done with an ionization chamber (IC) in the simulated prostate. The rectum was simulated by air-equivalent material (AEM). The volume superior to the IC placement was considered as the bladder. The extension of AEM volume could be varied. The vertical position of the IC placement could be shifted by ±1 cm to simulate the prostate motion parallel to the changes in bladder volume. The reality of the simulation was inspected. Three-millimeter-slice-increment computed tomography (CT) scans were taken for irradiation planning. The structure set was adapted to the phantom from a treated patient. Planning target volume was delineated according to the RTOG 0126 study. IMRT and 3D conformal radiation therapy (3D-CRT) plans were made. Prostate motion and rectum volume changes were simulated in the phantom. IC displacement was corrected by phantom shifting. The delivered dose was measured with IC in 7 cases using intensity-modulated radiation therapy (IMRT) and 3D-CRT fractions, and single square-shaped beams: anteroposterior (AP), posteroanterior (PA), and lateral (LAT). Variations from the calculated doses were slightly below 1% at IMRT and around 1% at 3D-CRT; below 4.5% at square AP beam; up to 9% at square PA beam; and around 0.5% at square LAT beam. Other authors have already shown that by using planning systems and ultrasonic and cone beam CT guidance, correction of organ motions in a real patient during prostate cancer IGRT does not have a significant dosimetric effect. The inspection of our phantom—as described here—ended with similar results. Our team suggested that our model is sufficiently realistic and can be used for IGRT and ART testing.     

A dosimetric evaluation of dose escalation for the radical treatment of locally advanced vulvar cancer by intensity-modulated radiation therapy

The purpose of this planning study was to determine whether intensity-modulated radiation therapy (IMRT) reduces the radiation dose to organs at risk (OAR) when compared with 3D conventional radiation therapy (3D-CRT) in patients with vulvar cancer treated by irradiation. This study also investigated the use of sequential IMRT boost (seq-IMRT) and simultaneous integrated boost (SIB-IMRT) for dose escalation in the treatment of locally advanced vulvar cancer. Five vulvar cancer patients treated in the postoperative setting and 5 patients treated with definitive intent (def-group) were evaluated. For the postoperative group, 3D-CRT and IMRT plans to a total dose (TD) of 45 Gy were generated. For the def-group, 4 plans were generated: a 3D-CRT and an IMRT plan to a TD of 56.4 Gy, a SIB-IMRT plan to a TD of 56 Gy, and a SIB-IMRT with dose escalation (SIB-IMRT-esc): TD of 67.2 Gy. Mean dose and dose-volume histograms were compared using Student's t-test. IMRT significantly (all p < 0.05) reduced the D_mean, V30, and V40 for all OAR in the adjuvant setting. The V45 was also significantly reduced for all OAR except the bladder. For patients treated in the def-group, all IMRT techniques significantly reduced the D_mean, V40, and V45 for all OAR. The mean femur doses with SIB-IMRT and SIB-IMRT-esc were 47% and 49% lower compared with 3D-CRT. SIB-IMRT-esc reduced the doses to the OAR compared with seq-3D-CRT but increased the D_max. for the small bowel, rectum, and bladder. IMRT reduces the dose to the OAR compared with 3D-CRT in patients with vulvar cancer receiving irradiation to a volume covering the vulvar region and nodal areas without compromising the dosimetric coverage of the target volume. IMRT for vulvar cancer is feasible and an attractive option for dose escalation studies.