Spatially fractionated radiotherapy (GRID) using helical tomotherapy.

Spatially fractionated radiotherapy (GRID) was designed to treat large tumors while sparing skin, and it is usually delivered with a linear accelerator using a commercially available block or multileaf collimator (LINAC-GRID). For deep-seated (skin to tumor distance (> 8 cm)) tumors, it is always a challenge to achieve adequate tumor dose coverage. A novel method to perform GRID treatment using helical tomotherapy (HT-GRID) was developed at our institution. Our approach allows treating patients by generating a patient-specific virtual GRID block (software-generated) and using IMRT technique to optimize the treatment plan. Here, we report our initial clinical experience using HT-GRID, and dosimetric comparison results between HT-GRID and LINAC-GRID. This study evaluates 10 previously treated patients who had deep-seated bulky tumors with complex geometries. Five of these patients were treated with HT-GRID and replanned with LINAC-GRID for comparison. Similarly, five other patients were treated with LINAC-GRID and replanned with HT-GRID for comparison. The prescription was set such that the maximum dose to the GTV is 20 Gy in a single fraction. Dosimetric parameters compared included: mean GTV dose (DGTV mean), GTV dose inhomogeneity (valley-to-peak dose ratio (VPR)), normal tissue doses (DNmean), and other organs-at-risk (OARs) doses. In addition, equivalent uniform doses (EUD) for both GTV and normal tissue were evaluated. In summary, HT-GRID technique is patient-specific, and allows adjustment of the GRID pattern to match different tumor sizes and shapes when they are deep-seated and cannot be adequately treated with LINAC-GRID. HT-GRID delivers a higher DGTV mean, EUD, and VPR compared to LINAC-GRID. HT-GRID delivers a higher DNmean and lower EUD for normal tissue compared to LINAC-GRID. HT-GRID plans also have more options for tumors with complex anatomical relationships between the GTV and the avoidance OARs (abutment or close proximity).

Dosimetric effect on pediatric conformal treatment plans using dynamic jaw with Tomotherapy HDA.

It is important to minimize the radiation dose delivered to healthy tissues in pediatric cancer treatment because of the risk of secondary malignancies. Tomotherapy HDA provides a dynamic jaw (DJ) delivery mode that creates a sharper penumbra at the craniocaudal ends of a target in addition to a fixed jaw (FJ) delivery mode. The purpose of this study was to evaluate its dosimetric effect on the pediatric cancer cases. We included 6 pediatric cases in this study. The dose profiles and plan statistics­target dose conformity, uniformity, organ-at-risk (OAR) mean dose, beam-on time, and integral dose­were compared for each case. Consequently, the target dose coverage and uniformity were similar for different jaw settings. The OAR dose sparing depended on its relative location to the target and disease sites. For example, in the head and neck cancer cases, the brain stem dose using DJ 2.5 was reduced by more than two-fold (2.4 Gy vs. 6.3 Gy) than that obtained with FJ 2.5. The integral dose with DJ 2.5 decreased by more than 9% compared with that with FJ 2.5. Thus, using dynamic jaw in pediatric cases could be critical to reduce a probability of a secondary malignancy.

Multi-institutional feasibility study of a fast patient localization method in total marrow irradiation with helical tomotherapy: a global health initiative by the international consortium of total marrow irradiation.

PURPOSE: To develop, characterize, and implement a fast patient localization method for total marrow irradiation. METHODS AND MATERIALS: Topographic images were acquired using megavoltage computed tomography (MVCT) detector data by delivering static orthogonal beams while the couch traversed through the gantry. Geometric and detector response corrections were performed to generate a megavoltage topogram (MVtopo). We also generated kilovoltage topograms (kVtopo) from the projection data of 3-dimensional CT images to reproduce the same geometry as helical tomotherapy. The MVtopo imaging dose and the optimal image acquisition parameters were investigated. A multi-institutional phantom study was performed to verify the image registration uncertainty. Forty-five MVtopo images were acquired and analyzed with in-house image registration software. RESULTS: The smallest jaw size (front and backup jaws of 0) provided the best image contrast and longitudinal resolution. Couch velocity did not affect the image quality or geometric accuracy. The MVtopo dose was less than the MVCT dose. The image registration uncertainty from the multi-institutional study was within 2.8 mm. In patient localization, the differences in calculated couch shift between the registration with MVtopo-kVtopo and MVCT-kVCT images in lateral, cranial-caudal, and vertical directions were 2.2 ± 1.7 mm, 2.6 ± 1.4 mm, and 2.7 ± 1.1 mm, respectively. The imaging time in MVtopo acquisition at the couch speed of 3 cm/s was <1 minute, compared with ≥15 minutes in MVCT for all patients. CONCLUSION: Whole-body MVtopo imaging could be an effective alternative to time-consuming MVCT for total marrow irradiation patient localization.

Voxel-based dose reconstruction for total body irradiation with helical tomotherapy.

PURPOSE: We have developed a megavoltage CT (MVCT)-based dose reconstruction strategy for total body irradiation (TBI) with helical TomoTherapy (HT) using a deformable registration model to account for the patient's interfraction changes. The proposed technique serves as an efficient tool for delivered dose verification and, potentially, plan adaptation. METHODS AND MATERIALS: Four patients with acute myelogenous leukemia treated with TBI using HT were selected for this study. The prescription was 12 Gy, 2 Gy/fraction, twice per day, given at least 6 h apart. The original plan achieved coverage of 80% of the clinical target volume (CTV) by the 12 Gy isodose surface. MVCTs were acquired prior to each treatment. Regions of interest were contoured on each MVCT. The dose for each fraction was calculated based on the MVCT using the HT planned adaptive station. B-spline deformable registration was conducted to establish voxel-to-voxel correspondence between the MVCT and the planning CT. The resultant deformation vector was employed to map the reconstructed dose from each fraction to the same point as the plan dose, and a voxel-to-voxel summed dose from all six fractions was obtained. The reconstructed dose distribution and its dosimetric parameters were compared with those of the original treatment plan. RESULTS: While changes in CTV contours occurred in all patients, the reconstructed dose distribution showed that the dose-volume histogram for CTV coverage was close (<1.5%) to that of the original plan. For sensitive structures, the differences between the reconstructed and the planned doses were less than 3.0%. CONCLUSION: Voxel-based dose reconstruction strategy that takes into account interfraction anatomical changes using MVCTs is a powerful tool for treatment verification of the delivered doses. This proposed technique can also be applied to adaptive TBI therapy using HT.

Dosimetric comparison of helical tomotherapy and linac-IMRT treatment plans for head and neck cancer patients.

The rapid development and clinical implementation of external beam radiation treatment technologies continues. The existence of various commercially available technologies for intensity-modulated radiation therapy (IMRT) has stimulated interest in exploring the differential potential advantage one may have compared with another. Two such technologies, Hi-Art Helical Tomotherapy (HT) and conventional medical linear accelerator-based IMRT (LIMRT) have been shown to be particularly suitable for the treatment of head and neck cancers. In this study, 23 patients who were diagnosed with stages 3 or 4 head and neck cancers, without evidence of distance metastatic disease, were treated in our clinic. Treatment plans were developed for all patients simultaneously on the HT planning station and on the Pinnacle treatment planning system for step-and-shoot IMRT. Patients were treated only on the HT unit, with the LIMRT plan serving as a backup in case the HT system might not be available. All plans were approved for clinical use by a physician. The prescription was that patients receive at least 95% of the planning target volume (PTV), which is 66 Gy at 2.2 Gy per fraction. Several dosimetric parameters were computed: PTV dose coverage; PTV volume conformity index; the normalized total dose (NTD), where doses were converted to 2 Gy per fraction to organs at risk (OAR); and PTV dose homogeneity. Both planning systems satisfied our clinic's PTV prescription requirements. The results suggest that HT plans had, in general, slightly better dosimetric characteristics, especially regarding PTV dose homogeneity and normal tissue sparing. However, for both techniques, doses to OAR were well below the currently accepted normal tissue tolerances. Consequently, factors other than the dosimetric parameters studied here may have to be considered when making a choice between IMRT techniques.

Evaluation of spatially fractionated radiotherapy (GRID) and definitive chemoradiotherapy with curative intent for locally advanced squamous cell carcinoma of the head and neck: initial response rates and toxicity.

PURPOSE: To present results and acute toxicity in 14 patients with bulky (>or=6 cm) tumors from locally advanced squamous cell carcinoma of the head and neck who received spatially fractionated radiotherapy (GRID) therapy to the bulky mass followed by concomitant chemoradiotherapy using simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT). METHODS AND MATERIALS: GRID therapy to the GTV was delivered by creating one treatment field with a checkerboard pattern composed of open-closed areas using a multileaf collimator. The GRID prescription was 20 Gy in one fraction. Chemotherapy started the day of GRID therapy and continued throughout the course of SIB-IMRT. The SIB-IMRT prescription was 66, 60, and 54 Gy to the planning target volume (PTV), intermediate-risk PTV, and low-risk PTV, respectively, in 30 fractions. RESULTS: With a median follow-up of 19.5 months (range, 2-38 months), the overall control rate of the GRID gross tumor volume was 79% (11 of 14). The most common acute skin and mucosal toxicities were Grade 3 and 2, respectively. CONCLUSION: For the treatment of locally advanced neck squamous cell carcinoma of the head and neck, GRID followed by chemotherapy and SIB-IMRT is well tolerated and yields encouraging clinical and pathologic responses, with similar acute toxicity profiles as in patients receiving chemoradiotherapy without GRID.

Pediatric craniospinal axis irradiation with helical tomotherapy: patient outcome and lack of acute pulmonary toxicity.

PURPOSE: To present the patient outcomes and risk of symptomatic acute radiation pneumonitis (ARP) in 18 pediatric patients treated with helical tomotherapy to their craniospinal axis for a variety of neoplasms. METHODS AND MATERIALS: A total of 18 patients received craniospinal axis irradiation with helical tomotherapy. The median age was 12 years (range, 2.5-21). The follow-up range was 3-48 months (median, 16.5). Of the 18 patients, 15 received chemotherapy in the neoadjuvant, adjuvant, or concomitant setting. Chemotherapy was tailored to the particular histologic diagnosis; 10 of 18 patients underwent surgical removal of the gross primary tumor. The patients were followed and evaluated for ARP starting at 3-6 months after completion of craniospinal axis irradiation. ARP was graded using the Common Toxicity Criteria, version 3. RESULTS: At the last follow-up visit, 14, 2, and 2 patients were alive without disease, alive with disease, and dead of disease, respectively. The cause-specific survival rate was 89% (16 of 18), disease-free survival rate was 78% (14 of 18), and overall survival rate was 89% (16 of 18). No patient had treatment failure at the cribriform plate. No patient developed symptoms of ARP. CONCLUSION: Craniospinal axis irradiation using helical tomotherapy yielded encouraging patient outcomes and acute toxicity profiles. Although large volumes of the lung received low radiation doses, no patient developed symptoms of ARP during the follow-up period.

Spatially fractionated (GRID) therapy for large and bulky tumors.

Avanced bulky tumors warrant aggressive therapy to attempt to maximize local control of the disease. Spatially fractionated radiation therapy (GRID) delivers a single-fraction of high dose radiation to these tumors with a curative or palliative goal. GRID therapy may be combined with fractionated radiation therapy or used in a therapeutic multi-modality setting to achieve control of the bulky disease. Current clinical data confirms the value of GRID therapy in the management of large volume of disease with an acceptable toxicity profile. GRID therapy has broad systemic effects leading to increases in a variety of cytokines that correlate with clinical outcome.

Therapeutic guidelines for the treatment of bone metastasis: a report from the American College of Radiology Appropriateness Criteria Expert Panel on Radiation Oncology.

Bone metastases remain a therapeutic challenge because of the diversity of the problems they cause, the relative paucity of data regarding their treatment, and the necessity for management by a multidisciplinary palliative care team. The American College of Radiology convened an Appropriateness Criteria Expert Panel on Radiation Oncology for the treatment of bone metastasis to create representative clinical case scenarios and then rank the appropriate use of treatment modalities as well as the most reasonable radiotherapy dose schema and treatment planning methods. Here we present both the resulting Appropriateness Criteria and the rationale for making these decisions. The treatment recommendations are placed within the larger framework of the role of radiation in palliative care by discussing the efficiency of palliative radiotherapy schedules, cost effectiveness issues, and the need for additional research regarding the proper multidisciplinary care of patients with symptomatic bone metastasis.

A prospective cohort study of microvascular decompression and Gamma Knife surgery in patients with trigeminal neuralgia.

OBJECT: The aim of this study was to analyze 1 surgeon's 4-year experience with microvascular decompression ([MVD], 36 patients) and Gamma Knife surgery ([GKS], 44 patients) in 80 consecutive patients with trigeminal neuralgia (TN). METHODS: The authors conducted a prospective cohort study from March 1999 to December 2003 with an independent clinical assessment of the results and serial patient satisfaction surveys. All patients completed a 2004 patient satisfaction survey (0.5-5 years postoperative), and 70% of surviving patients completed the same survey in 2007 (3.9-8.5 years postoperative). Follow-up was undertaken in 100% of the patients (mean 3.4 +/- 2.14 years, range 0.17-8.5 years). RESULTS: Respective initial and latest follow-up raw pain-free rates were 100 and 80.6% for MVD and 77.3 and 45.5% for GKS. The median time to the maximal benefit after GKS was 4 weeks (range 1 week-6 months). Respective initial, 2-, and 5-year actuarial pain-free rates were 100, 88, and 80% for MVD and 78, 50, and 33% for GKS (p = 0.0002). The relative risk of losing a pain-free status by 5 years posttreatment was 3.35 for patients in the GKS group compared with the MVD group. Initial and 5-year actuarial rates for >or= 50% pain relief after GKS were 100 and 80%, respectively. The respective rates of permanent mild and severe sensory loss were 5.6 and 0% for patients in the MVD group, as opposed to 6.8 and 2.3% for patients in the GKS group. Anesthesia dolorosa did not occur during the study. Both procedures enjoyed a high degree of early patient satisfaction (95-100%). Microvascular decompression maintained the same rate of patient satisfaction, but satisfaction with GKS decreased to 75% as pain control waned. Twenty-three patients (29%) died of causes unrelated to the TN or the surgical intervention during the follow-up, and their pain status was known at the time of death. Statistically significant intergroup differences for the MVD versus GKS cohorts were age (median 54 years, range 36-70 years vs median 74 years, range 48-92 years, respectively), preoperative symptom duration (median 2.58 years, range 0.33-15 years vs median 7.5, range 0.6-40 years, respectively), and the presence of major comorbidities (2.8 vs 58.3%, respectively). CONCLUSIONS: In this nonrandomized prospective cohort trial of selected patients with potentially relevant intergroup differences, MVD was significantly superior to GKS in achieving and maintaining a pain-free status in those with TN and provided similar early and superior longer-term patient satisfaction rates compared with those for GKS. The complications of wound cerebrospinal fluid leakage, hearing loss, and persistent diplopia (1 case each in the MVD group) were not seen after GKS.

Retrospective evaluation of pediatric cranio-spinal axis irradiation plans with the Hi-ART tomotherapy system.

Helical tomotherapy (HT) can be used for the delivery of cranio-spinal axis irradiation (CSAI) without the need for beam matching of conventional linac-based external beam irradiation. The aim of this study is to retrospectively evaluate HT plans used for treatment in nine patients treated with CSAI. Helical tomotherapy cranio-spinal axis irradiation (HT-CSAI) plans were created for each patient. Average length along the cranio-spinal axis of the PTV was 65.6 cm with a range between 53 and 74 cm. Treatment planning optimization and plan evaluation parameters were obtained from the HT planning station for each of the nine patients. PTV coverage by the 95% isodose surface ranged between 98.0 to 100.0% for all nine patients. The clinically acceptable dose variation within the PTV or tolerance range was between 0.7 and 2.5% for all nine patients. Doses to the organs at risk were clinically acceptable. An increasing length along the longitudinal axis of the PTV did not consistently increase the beam-on time indicating that using a larger jaw width had a greater impact on treatment time. With a larger jaw width it is possible to substantially reduce the normalized beam-on treatment time without compromising plan quality and sparing of organs at risk. By using a larger jaw width or lower modulation factor or both, normalized beam-on times were decreased by up to 61% as compared to the other evaluated treatment plans. From the nine cases reported in this study the minimum beam-on time was achieved with a jaw width of 5.0 cm, pitch of 0.287 and a modulation factor of 2.0. Large and long cylindrical volumes can be effectively treated with helical tomotherapy with both clinically acceptable dose distribution and beam-on time.

Dosimetric comparison of helical tomotherapy and Gamma Knife stereotactic radiosurgery for single brain metastasis.

BACKGROUND: Helical Tomotherapy (HT) integrates linear accelerator and computerized tomography (CT) technology to deliver IMRT. Targets are localized (i.e. outlined as gross tumor volume [GTV] and planning target volume [PTV]) on the planning kVCT study while daily MVCT is used for correction of patient's set-up and assessment of inter-fraction anatomy changes. Based on dosimetric comparisons, this study aims to find dosimetric equivalency between single fraction HT and Gamma Knife stereotactic radiosurgery (GKSRS) for the treatment of single brain metastasis. METHODS: The targeting MRI data set from the GKSRS were used for tomotherapy planning. Five patients with single brain metastasis treated with GKSRS were re-planned in the HT planning station using the same prescribed doses. There was no expansion of the GTV to create the PTV. Sub-volumes were created within the PTV and prescribed to the maximum dose seen in the GKSRS plans to imitate the hot spot normally seen in GKSRS. The PTV objective was set as a region at risk in HT planning using the same prescribed dose to the PTV periphery as seen in the corresponding GKSRS plan. The tumor volumes ranged from 437-1840 mm(3). RESULTS: Conformality indices are inconsistent between HT and GKSRS. HT generally shows larger lower isodose line volumes, has longer treatment time than GKSRS and can treat a much larger lesion than GKSRS. Both HT and GKSRS single fraction dose-volume toxicity may be prohibitive in treating single or multiple lesions depending on the number and the sizes of the lesions. CONCLUSION: Based on the trend for larger lower dose volumes and more constricted higher dose volumes in HT as compared to GKSRS, dosimetric equivalency was not reached between HT and GKSRS.

Feasibility of cranio-spinal axis radiation with the Hi-Art tomotherapy system.

BACKGROUND AND PURPOSE: Helical tomotherapy can eliminate the need for junction lines. The goal of this study is to evaluate tomotherapy in the delivery of CSA radiation and measurement of plan quality using physical parameters in comparing conventional (CSA-RT) and helical tomotherapy (CSA-TOMO) plans. PATIENTS AND METHODS: CSA-TOMO and CSA-RT plans were created for dosimetric comparison. Integral dose values were calculated. The ratios D50% (dose received by 50% of the organ at risk's volume) and D10% (dose received by 10% of the organ at risk's volume) were calculated representing large volumes and small volumes of organs at risk receiving significant dose. RESULTS: When considering D50% and D10%, CSA-TOMO has a dosimetric advantage over CSA-RT for most organs at risk. The body integral dose was higher for the CSA-TOMO plan by approximately 6.5%. CONCLUSIONS: Tomotherapy is a feasible alternative for treatment of CSA. Analysis shows that tomotherapy improves dose ratios over conventional radiation for most organs at risk. The impact of a small increase in whole body integral dose is unknown. Long-term follow-up will be needed to answer this question as others have argued of the possibility of increased risk of secondary malignancies due to delivery of radiotherapy with IMRT.

Fast radiographic film calibration procedure for helical tomotherapy intensity modulated radiation therapy dose verification.

Film dosimetry offers an advantageous in-phantom planar dose verification tool in terms of spatial resolution and ease of handling for quality assurance (QA) of intensity modulated radiation therapy (IMRT) plans. A critical step in the success of such a technique is that the film calibration be appropriately conducted. This paper presents a fast and efficient film calibration method for a helical tomotherapy unit using a single sheet of film. Considering the unique un-flattened cone shaped profile from a helical tomotherapy beam, a custom leaf control file (sinogram) was created, to produce a valley shaped intensity pattern. There are eleven intensity steps in the valley pattern, representing varying dose values from 38 to 265 cGy. This dose range covers the most commonly prescribed doses in fractionated IMRT treatments. An ion chamber in a solid water phantom was used to measure the dose in each of the eleven steps. For daily film calibration the whole procedure, including film exposure, processing, digitization and analysis, can be completed within 15 min, making it practical to use this technique routinely. This method is applicable to film calibration on a helical tomotherapy unit and is particularly useful in IMRT planar dose verification due to its efficiency and reproducibility. In this work, we characterized the dose response of the KODAK EDR2 ready-pack film which was used to develop the step valley dose maps and the IMRT QA planar doses. A comparison between the step valley technique and multifilm based calibration showed that both calibration methods agreed with less than 0.4% deviation in the clinically useful dose ranges.

Relative roles of microsurgery and stereotactic radiosurgery for the treatment of patients with cranial meningiomas: a single-surgeon 4-year integrated experience with both modalities.

OBJECT: The authors sought to assess the respective roles of microsurgery and gamma knife surgery (GKS) in the treatment of patients with meningiomas. METHODS: The authors culled from a 4-year prospective database data on 74 cases of meningiomas. Thirty-eight were treated with GKS and 35 with microsurgery. Simpson Grade 1 or 2 resection was achieved in 86.1 % of patients who underwent microsurgery. Patients who underwent GKS received a mean margin dose of 16.4 Gy (range 14-20 Gy). The mean tumor coverage was 94.7%, and the mean conformity index was 1.76. Significant differences between the two treatment groups (GKS compared with microsurgery) included age (mean 60 compared with 50.7 years), volume (mean 7.85 cm3 compared with 44.4 cm3), treatment history (55.3% compared with 14.3%), and tumor location (cavernous sinus/petroclival, 14 compared with three). The median follow up was 21.5 months (range 1.5-50 months). In patients with benign meningiomas GKS tumor control was 96.8% with one recurrence at the margin. The recurrence rate was zero of 27 for Simpson Grade 1 or 2 resection and three of four for higher grades in those patients who underwent microsurgery. There was no procedure-related mortality or permanent major neurological morbidity. The mean Karnofsky Performance Scale score was maintained for both forms of treatment. Symptoms improved in 48.4% of patients undergoing microsurgery and 16.7% of those who underwent GKS. Transient and permanent cranial nerve morbidity was 7.9 compared with 2.9%, and 5.3 compared with 8.5% for GKS and microsurgery, respectively. In a patient satisfaction survey 93.1% of microsurgery patients and 91.2% of GKS patients were highly satisfied. CONCLUSIONS: Both GKS and microsurgery serve important roles in the overall management of patients with meningiomas. Both are safe and effective and provide high degrees of satisfaction when used for differentially selected patients.

Application of intensity-modulated radiation therapy for pediatric malignancies.

Novel radiation therapy delivery techniques have moved very slowly in the field of pediatric oncology. Some collaborative groups allow new radiation therapy delivery techniques in their trials. In many instances, the option of using these techniques is not addressed. These newer techniques of radiation delivery have the potential to reduce the probability of the common late effects of radiation and at the same time, potentially improve upon control and survival. The purpose of this study is to show the feasibility of IMRT in pediatric patients. No treatment results or toxicities will be presented. Five patients with a variety of pediatric malignancies received intensity-modulated radiation therapy (IMRT) at our institution as part of their disease management. A rigid immobilization device was developed for each patient and a computed tomography (CT) simulation was performed in the treatment position. In 3 of the patients, magnetic resonance imaging (MRI) scans were coregistered with the planning CT to facilitate target and critical structure delineation. In all but 1 patient, coplanar beam arrangements were used in the IMRT planning process. All IMRT plans exhibited a high degree of conformality. Dose homogeneity inside the tumor and rapid dose falloff outside the target volume is characteristic of IMRT plans, which allows for improved normal tissue sparing. Dose distributions were obtained for all plans, as well as dose and volume relationship histograms, to evaluate the fitness of the plans. IMRT is a viable alternative to conventional treatment techniques for pediatric cancer patients. The improved dose distributions coupled with the ease of delivery of the IMRT fields make this technique very attractive, especially in view of the potential to increase local control and possibly improve on survival.

Intensity-modulated radiation therapy reduces the dose to normal tissue in T2N0M0 squamous cell carcinoma of the glottic larynx.

The purpose of this paper was to compare intensity-modulated radiation therapy (IMRT) and conventional planning for T2N0M0 squamous cell carcinoma (SQCC) of the glottic larynx. Three patients with T2N0M0 SQCC are presented who were treated with IMRT. Conventional plans were also generated for comparison purposes. Isodose distributions and dose-volume histograms (DVHs) were generated for all the plans to evaluate the fitness of the plan as well as the differential benefit of IMRT vs. conventional treatment. The isodose distributions that were obtained by the IMRT plan are much more conformal to the planning target volume (PTV) and clearly show that less healthy tissue is subjected to a high-dose level, thus reducing toxicity. IMRT offers better comformality without compromising the PTV coverage and delivers less dose to normal tissues as compared to conventional radiation therapy in T2N0M0 SQCC of the glottic larynx. With an increase in conformality, it is expected to have an increase in the therapeutic ratio.

Accelerated cerebral vasculopathy after radiation therapy to the brain.

Brain irradiation is commonly used for many primary brain malignancies. We will present two cases of post-radiation vasculopathy of large arteries of patients who received radiation therapy to the brain as part of their tumor management. We will underscore the significance of this condition and suggest the overall management of patients receiving brain radiation at an early age.