Chemical Composition, Toxicity, and Repellency of Essential Oils from Three Hedychium Species Against Stored-Product Insects.

Stored products are constantly infested by insects, so finding eco-friendly bioinsecticides for insect management is important. The work aimed to assess the insecticidal and repellent activity of essential oil (EO) from Hedychium glabrum S. Q. Tong, Hedychium coronarium Koen., and Hedychium yunnanense Gagnep. against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. Results showed that 88 chemical components were identified in the extracted Hedychium EOs, indicating that they exhibited diversity in components. According to principal component analysis (PCA), the composition of the EO from the H. yunnanense stem and leaf (EOHYSL) was significantly different from other EOs due to the different organs and species. The biological activity also varied continuously with plant species and organs. Only the EO of H. yunnanense (EOHY) showed strong fumigant toxicity. While in the contact tests, EOHGR showed the strongest toxicity effect on L. bostrychophila, with a LC50 value of 71.76 µg/cm2, which was closest to the positive control (Pyrethrin). All EOs had remarkable repellent activities against the three target insects, and repellency increased with concentration. According to the results of the comprehensive score, EOHY had the highest potential, which ranged from 0.7999 to 0.8689. Thus, Hedychium EOs possess potential biorational traits to be biological insecticides.

Chemical Composition and Insecticidal Activities of Blumea balsamifera (Sambong) Essential Oil Against Three Stored Product Insects.

Blumea balsamifera (L.) DC. (Asteraceae), also known as sambong, is a perennial herb used in China for medicinal purposes. The essential oil (EO) of B. balsamifera was extracted by hydrodistillation. Thirty chemical components of the EO were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC, accounting for 88.0% (w/w) of the total oil. The EO of B. balsamifera was mainly composed of monoterpenes and sesquiterpenes, in which borneol (23.3%), ß-caryophyllene (20.9%) and camphor (11.8%) were the major components. The insecticidal activities of the EO and its three main compounds against Tribolium castaneum, Lasioderma serricorne and Sitophilus oryzae were evaluated. The results of bioassays displayed that the EO of B. balsamifera did not have fumigant toxicity to the three target insects, but exhibited significant contact activity against L. serricorne (LD50 = 12.4 µg/adult) and S. oryzae (LD50 = 44.4 µg/adult). Meanwhile, the EO showed a notable repellent effect on T. castaneum at all testing concentrations and a general repellent effect on S. oryzae at high concentrations (78.63 nL/cm2). ß-Caryophyllene showed the best performance in the contact toxicity bioassays against the three insects. The results indicated that B. balsamifera has the potential to be used as a source of botanical insecticides for the control of stored-product insects.

Assessment of Contact Toxicity and Repellent Effects of Essential Oils from Piper Plants Piper yunnanense and Piper boehmeriifolium against Three Stored-Product Insects.

Storage is a crucial part during grain production for the massive spoilage caused by stored product insects. Essential oils (EOs) of plant origin have been highly recommended to combating insects which are biodegradable and safe mode of action. Hence, to make the fullest use of natural resources, essential oils of different parts from Piper yunnanense (the whole part, PYW; fruits, PYF; leaves, PYL) and Piper boehmeriifolium (leaves, PBL) were extracted by steam distillation method in the present study. Gas chromatography-mass spectrometry (GC-MS) characterization revealed bicyclogermacrene (PYW), γ-muurolene (PYF), δ-cadinene (PYL) and methyl 4,7,10,13,16,19-docosahexaenoate (PBL) as the principal compound of each essential oil. Sesquiterpene hydrocarbons were also recognized as the richest class accounting for 56.3 %-94.9 % of the total oil. Three storage pests, Tribolium castaneum, Lasioderma serricorne and Liposceis bostrychophila, were exposed to different concentrations of EOs to determine their insecticidal effects. All tested samples performed modest contact toxicity in contrast to a bioactive ingredient pyrethrin, among which the most substantial effects were observed in PYF EOs against T. castaneum (35.84 µg/adult), PBL EOs against L. serricorne (15.76 µg/adult) and PYW EOs against L. bostrychophila (57.70 µg/cm2 ). In terms of repellency tests, essential oils of PYF at 78.63 nL/cm2 demonstrated to have a remarkable repellence against T. castaneum at 2h and 4h post-exposure. The investigations indicate diverse variations in the chemical profiles and insecticidal efficacies of P. yunnanense and P. boehmeriifolium EOs, providing more experimental evidence for the use of the Piper plants.

The effectiveness of adjustable oral appliance for older adult patients with obstructive sleep apnea syndrome.

BACKGROUND: Oral appliance (OA) treatment for obstructive sleep apnea syndrome (OSAS) has attracted more and more attention due to its low price, comfort, portable and non-invasion. This study aimed to investigate the clinical effectiveness of adjustable oral appliance on older adult patients with OSAS. METHODS: Thirty older adult patients diagnosed with OSAS were chosen as the study participants and received an adjustable OA for 6 months. Then, the patients were subjected to a polysomnographic examination, Berlin Questionnaire (BQ) scale questionnaire, and cone beam computer tomography (CBCT) analytical measurement to evaluate their symptom improvement and the morphologic changes of the upper airway. RESULTS: After treatment with adjustable oral appliance for six months, the results showed that there was an improvement of different degrees in the subjective symptoms. Apnea hypopnea index (AHI) had decreased from (27.65±1.31) per hour to (6.74±0.75) per hour (P<0.05); the maximum apnea time (MAT) had decreased from 43.82±2.69 to 21.37±3.18 s (P<0.05); the average oxygen saturation (MSaO2) had increased from (89.24±7.27)% to (92.69±4.46)%; the lowest oxygen saturation (LSaO2) from (81.85±8.31)% to (86.93±4.45)%. Moreover, the CBCT scanning analysis showed that the minimal sagittal diameter, sectional area, and the volume of the palatopharynx, as well as the sagittal diameter and volume of the glossopharynx significantly increased. CONCLUSIONS: The adjustable OA had considerable clinical efficacy and comfort in older adult OSAS patients by enlarging the palatopharynx and glossopharynx.

Intensity-modulated radiosurgery with rapidarc for multiple brain metastases and comparison with static approach.

Rotational RapidArc (RA) and static intensity-modulated radiosurgery (IMRS) have been used for brain radiosurgery. This study compares the 2 techniques from beam delivery parameters and dosimetry aspects for multiple brain metastases. Twelve patients with 2-12 brain lesions treated with IMRS were replanned using RA. For each patient, an optimal 2-arc RA plan from several trials was chosen for comparison with IMRS. Homogeneity, conformity, and gradient indexes have been calculated. The mean dose to normal brain and maximal dose to other critical organs were evaluated. It was found that monitor unit (MU) reduction by RA is more pronounced for cases with larger number of brain lesions. The MU-ratio of RA and IMRS is reduced from 104% to 39% when lesions increase from 2 to 12. The dose homogeneities are comparable in both techniques and the conformity and gradient indexes and critical organ doses are higher in RA. Treatment time is greatly reduced by RA in intracranial radiosurgery, because RA uses fewer MUs, fewer beams, and fewer couch angles.

Feasibility and advantages of using flattening filter-free mode for radiosurgery of multiple brain lesions.

PURPOSE: The 6-MV flattening filter-free mode (6F) of the Varian TrueBeam (Varian Medical Systems, Palo Alto, CA) enables faster dose delivery and shortens treatment time, which are especially beneficial for stereotactic radiosurgery. This study is to evaluate the feasibility and advantages of using 6F in stereotactic radiosurgery treatment of multiple brain lesions in comparison with regular 6-MV mode (6X). MATERIALS AND METHODS: Ten patients having 2-12 brain metastases treated by intensity modulated stereotactic radiosurgery were selected for this study. For each patient, 2 RapidArc (RA; Varian Medical Systems) plans were generated: one using the 6F mode with a dose rate of 1400 monitor units (MU)/minute and another using the regular 6X mode of 600 MU/minute for a Varian TrueBeam linac. For each patient, both plans employed the same beam arrangement and optimization process. RESULTS: The dosimetric parameters of homogeneity, conformity, and gradient indices were calculated and found to be comparable in the 6F and 6X plans for each patient. The mean dose to the normal brain and maximal doses to brainstem, chiasm, eyes, and optical nerves were also comparable in both RA plans using either 6F or 6X. The total number of MUs in the RA plans using 6F was 10%-20% more than that in the RA plan using 6X, but the beam-on-time was much less if 6F was used for planning and dose delivery (50% less). CONCLUSIONS: The fast delivery of the 6F beam is not only beneficial in stereotactic radiosurgery of a single brain lesion, but also for treating multiple brain lesions (2-12 lesions in this study group). Due to the beam falloff away from the central axis for large field sizes, more MUs are needed for 6F beams as compared with 6X. However, for the 6F mode with 1400 MU/minute, the delivery times are still much shorter compared with the 6X mode, thus greatly shortening the treatment time.

Reconstruction of alveolar bone defects using bone morphogenetic protein 2 mediated rabbit dental pulp stem cells seeded on nano-hydroxyapatite/collagen/poly(L-lactide).

The objective of the present study was to evaluate the capacity of a tissue-engineered bone complex of recombinant human bone morphogenetic protein 2 (rhBMP-2)-mediated dental pulp stem cells (DPSCs) and nano-hydroxyapatite/collagen/poly(L-lactide) (nHAC/PLA) to reconstruct critical-size alveolar bone defects in New Zealand rabbit. Autologous DPSCs were isolated from rabbit dental pulp tissue and expanded ex vivo to enrich DPSCs numbers, and then their attachment and differentiation capability were evaluated when cultured on the culture plate or nHAC/PLA. The alveolar bone defects were treated with nHAC/PLA, nHAC/PLA+rhBMP-2, nHAC/PLA+DPSCs, nHAC/PLA+DPSCs+rhBMP-2, and autogenous bone (AB) obtained from iliac bone or were left untreated as a control. X-ray and a polychrome sequential fluorescent labeling were performed postoperatively and the animals were sacrificed 12 weeks after operation for histological observation and histomorphometric analysis. Our results showed that DPSCs expressed STRO-1 and vementin, and favored osteogenesis and adipogenesis in conditioned media. DPSCs attached and spread well, and retained their osteogenic phenotypes on nHAC/PLA. The rhBMP-2 could significantly increase protein content, alkaline phosphatase activity/protein, osteocalcin content, and mineral formation of DPSCs cultured on nHAC/PLA. The X-ray graph, the fluorescent, histological observation, and histomorphometric analysis showed that the nHAC/PLA+DPSCs+rhBMP-2 tissue-engineered bone complex had an earlier mineralization and more bone formation inside the scaffold than nHAC/PLA, nHAC/PLA+rhBMP-2, and nHAC/PLA+DPSCs, or even autologous bone. Implanted DPSCs' contribution to new bone was detected through transfected eGFP genes. Our findings indicated that stem cells existed in adult rabbit dental pulp tissue. The rhBMP-2 promoted osteogenic capability of DPSCs as a potential cell source for periodontal bone regeneration. The nHAC/PLA could serve as a good scaffold for autologous DPSC seeding, proliferation, and differentiation. The tissue-engineered bone complex with nHAC/PLA, rhBMP-2, and autologous DPSCs might be a better alternative to autologous bone for the clinical reconstruction of periodontal bone defects.

Comparison of daily cone-beam computed tomography and kilovoltage planar imaging for target localization in prostate cancer patients following radical prostatectomy.

PURPOSE: To review our initial clinical experience with image-guided radiation therapy (IGRT) using cone-beam computed tomography (CBCT) for prostate bed localization in post-radical prostatectomy (RP) patients and to compare shift and acute toxicity results to our previously published IGRT experience with daily kV planar imaging. METHODS AND MATERIALS: Fifty patients treated with intensity modulated radiation therapy (IMRT) who had image guidance using either CBCT (n = 23) or kV planar imaging (n = 27) following RP were analyzed. Shifts were recorded in anterior-posterior, superior-inferior, and left-right axes. Total error was defined as the shift from initial setup based on skin markings to isocenter. Prostate bed motion (PBM) was defined as the change in prostate bed position relative to bones. Acute toxicity was graded according to the Radiation Therapy Oncology Group morbidity criteria. RESULTS: Total error (TE) was measured in 752 CBCTs and 725 kV planar image pairs. PBM was measured in 585 CBCTs and 384 kV planar image pairs. The average magnitudes of TE and PBM in the anterior-posterior, superior-inferior, and left-right axes were greater with kV planar imaging compared to CBCT. Frequencies of acute grade 2 gastrointestinal (13% vs 7%, P = .7) and genitourinary (9% vs 11%, P = 1.0) were similar for CBCT and kV planar imaging patients. No toxicities greater than grade 2 were seen. CONCLUSIONS: These results suggest that although the magnitudes of TE and PBM were larger with kV planar compared to CBCT, the levels of acute toxicity were acceptable and comparable between the two. The reasons for the differences are unclear, but we postulate that discernment of the prostate bed on the CBCT is more difficult. Further investigation is necessary to determine the reason for the shift differences and to evaluate the benefits and risks of CBCT in this setting.

Evaluation of patient setup uncertainty of optical guided frameless system for intracranial stereotactic radiosurgery.

The optically-guided frameless system (OFLS) has been used in our clinic for intracranial stereotactic radiosurgery (SRS) since 2006, as it is especially effective in IMRT-based radiosurgery (IMRS), which allows treating multiple brain lesions simultaneously using single isocenter approach. This study reports our retrospective analysis of patient setup accuracy using this system. The OFLS consists of a bite block with fiducial markers and an infra-red camera system. To test reproducibility, patients are taken for reseat verification after bite block construction. Upon the completion of radiosurgery planning, the isocenter position(s) and images are sent to the optical guidance computer where fiducials are manually registered from the CT scan. During treatment, patient setup is monitored and guided by the camera readings on the fiducials. In addition, two orthogonal kV images are acquired and used as an isocenter verification tool. In addition, we have analyzed the reseat and fiducial digitization data of 56 patients. Retrospective comparison of kV images with reference images has been carried out for all the patients to evaluate actual patient setup accuracy at the time of treatment. The histogram of the findings shows that 82.2% of patients had 3D isodisplacement (E < or = 1 mm; 5.2% had 1< E < or = 2 mm). Hence, for 87.5 % of the patients in the study, treatments were finished under the optical guidance with a maximum setup error of 2 mm and the median setup error of 0 mm. For the remaining 12.5% of patients in the study, the isodisplacements were greater than 2 mm and the treatment records showed that those patients were repositioned, guided by the orthogonal kV-images. It is found that the OFLS in the SRS treatment has acceptable accuracy when used in conjunction with orthogonal kV images, and the use of orthogonal kV images as a verification tool ensures the efficacy of frameless localization in the radiosurgery treatment.

The interactions between rat-adipose-derived stromal cells, recombinant human bone morphogenetic protein-2, and beta-tricalcium phosphate play an important role in bone tissue engineering.

Cells, scaffolds, and growth factors are the three main factors for creating a stem-cell-based tissue-engineered construct, but the interactions between three factors are not very clear. We hereby explored the interactions between rat-adipose-derived stromal cells (rASCs), recombinant human bone morphogenetic protein-2 (rhBMP-2), and beta-tricalcium phosphate (beta-TCP) to provide evidence for their application in bone tissue engineering by evaluating the protein adsorption of beta-TCP, the cell attachment, alkaline phosphatase (ALP) activity/protein, osteocalcin (OCN) content, mineral formation, calcium content, phosphonium content, cell vitality, gene expression, and implantation in the backs of severe combined immunodeficient mice of rhBMP-2 preinducing rASCs seeded onto beta-TCP. The results showed that beta-TCP could adsorb the proteins from the media. The attachment, proliferation, and osteogenic properties of rASCs were supported by beta-TCP, as revealed using scanning electron microscopy. Compared with rASCs cultured on the culture plate, rASCs cultured on beta-TCP had significantly higher ALP activity/protein, OCN content, and mineral formation. These values for rASCs cultured on beta-TCP with rhBMP-2 increased most significantly. The rhBMP-2 significantly increased the calcium content, phosphonium content, and ALP, type I collagen, and OCN mRNA levels of rASCs cultured on beta-TCP. The methylthiazol tetrazolium method revealed that the vitality of rASCs cultured on beta-TCP with or without rhBMP-2 for 4, 7, and 28 days in vitro was insignificantly different. After 8 and 12 weeks of implantation, each group displayed increased bone formation over the 12-week period. The percentage of the new bone formed areas for beta-TCP/rhBMP-2 and beta-TCP was not significantly different. This value for rASCs/beta-TCP construct was significantly higher than that for beta-TCP group, but the maximal and robust bone formation was presented in rASCs/beta-TCP with rhBMP-2. The results implied that stem cells existed in adult rat adipose tissue. beta-TCP could adsorb rhBMP-2 from the media and had osteoinductivity when alone implanted in the back of severe combined immunodeficient mice. beta-TCP was also sufficient to trigger the differentiation of rASCs toward an osteoblastic phenotype without the addition of osteogenic factor. The rhBMP-2 could better sufficiently induce osteogenic differentiation of rASCs seeded onto beta-TCP. The rASCs and rhBMP-2 could promote the dissolution of beta-TCP to provide Ca2+ and PO4(3-) needed for bone formation. The interactions between the three factors could provide an optimizing microenvironment for osteogenic differentiation of rASCs, and this might be essential for sufficient and timely bone formation in vivo. This study may provide insight into the clinical repair of bone defect with ASCs+beta-TCP+rhBMP-2 construct.

Single-isocenter frameless intensity-modulated stereotactic radiosurgery for simultaneous treatment of multiple brain metastases: clinical experience.

PURPOSE: To describe our clinical experience using a unique single-isocenter technique for frameless intensity-modulated stereotactic radiosurgery (IM-SRS) to treat multiple brain metastases. METHODS AND MATERIALS: Twenty-six patients with a median of 5 metastases (range, 2-13) underwent optically guided frameless IM-SRS using a single, centrally located isocenter. Median prescription dose was 18 Gy (range, 14-25). Follow-up magnetic resonance imaging (MRI) and clinical examination occurred every 2-4 months. RESULTS: Median follow-up for all patients was 3.3 months (range, 0.2-21.3), with 20 of 26 patients (77%) followed up until their death. For the remaining 6 patients alive at the time of analysis, median follow-up was 14.6 months (range, 9.3-18.0). Total treatment time ranged from 9.0 to 38.9 minutes (median, 21.0). Actuarial 6- and 12-month overall survivals were 50% (95% confidence interval [C.I.], 31-70%) and 38% (95% C.I., 19-56%), respectively. Actuarial 6- and 12-month local control (LC) rates were 97% (95% C.I., 93-100%) and 83% (95% C.I., 71-96%), respectively. Tumors 1.5 cm (98% vs. 90%, p = 0.008). New intracranial metastatic disease occurring outside of the treatment volume was observed in 7 patients. Grade >or=3 toxicity occurred in 2 patients (8%). CONCLUSION: Frameless IM-SRS using a single-isocenter approach for treating multiple intracranial metastases can produce clinical outcomes that compare favorably with those of conventional SRS in a much shorter treatment time (<40 minutes). Given its faster treatment time, this technique is appealing to both patients and personnel in busy clinics.

Toxicity analysis of postoperative image-guided intensity-modulated radiotherapy for prostate cancer.

PURPOSE: To report on the acute and late gastrointestinal (GI) and genitourinary (GU) toxicity associated with a unique technique of image-guided radiotherapy (IGRT) in patients undergoing postprostatectomy irradiation. METHODS AND MATERIALS: Fifty patients were treated with intensity-modulated radiation therapy (IMRT) after radical prostatectomy. Daily image guidance was performed to localize the prostate bed using kilovoltage imaging or cone-beam computed tomography. The median prescription dose was 68 Gy (range, 62-68 Gy). Toxicity was graded every 3 to 6 months according to the Common Terminology Criteria for Adverse Events version 3.0. RESULTS: The median follow-up was 24 months (range, 13-38 months). Grade 2 acute GI and GU events occurred in 4 patients (8%) and 7 patients (14%), respectively. No Grade 3 or higher acute GI or GU toxicities were observed. Late Grade 2 GI and GU events occurred in 1 patient (2%) and 8 patients (16%), respectively. Only a single (2%) Grade 3 or higher late toxicity was observed. CONCLUSIONS: Image-guided IMRT in the postprostatectomy setting is associated with a low frequency of acute and late GI/GU toxicity. These results compare more favorably to radiotherapy techniques that do not use in-room image-guidance, suggesting that daily prostate bed localization may reduce the incidence of adverse events in patients undergoing postprostatectomy irradiation.

Optically-guided frameless linac-based radiosurgery for brain metastases: clinical experience.

The purpose of this study was to describe our clinical experience using optically-guided linear accelerator (linac)-based frameless stereotactic radiosurgery (SRS) for the treatment of brain metastases. Sixty-five patients (204 lesions) were treated between 2005 and 2008 with frameless SRS using an optically-guided bite-block system. Patients had a median of 2 lesions (range, 1-13). Prescription dose ranged from 14 to 22 Gy (median, 18 Gy) and was given in a single fraction. Clinical and radiographic evaluation occurred every 2-4 months following treatment. At a median follow-up of 6.2 months, actuarial survival at 12 months was 40% [95% confidence interval (CI), 28-52). Of 135 lesions that were evaluable for local control (LC), 119 lesions (88%) did not show evidence of progression. Actuarial 12 month LC was 76% (95% CI, 66-86). Tumors 2 cm. Adverse events occurred in three patients (5%). Optically-guided linac-based frameless SRS can produce clinical outcomes that compare favorably to frame-based techniques. As this technique is convenient to use and allows for the uncomplicated delivery of hypofractionated radiotherapy, frameless SRS will likely have an increasingly important role in the management of brain metastases.

Intracranial application of IMRT based radiosurgery to treat multiple or large irregular lesions and verification of infra-red frameless localization system.

We have employed a frameless localization system for intracranial radiosurgery, utilizing a custom biteblock with fiducial markers and an infra-red camera for set-up and monitoring patient position. For multiple brain metastases or large irregular lesions, we use a single-isocenter intensity-modulated approach. We report our quality assurance measurements and our experience using Intensity Modulated Radiosurgery (IMRS) to treat such intracranial lesions. A phantom with integrated targets and fiducial markers was utilized to test the positional accuracy of the system. The frameless localization system was used for patient setup and target localization as well as for motion monitoring during treatment. Inverse optimization planning gave satisfactory dose coverage and critical organ sparing. Patient setup was guided by the infrared camera through fine adjustment in three translational and three rotational degrees for isocenter localization and verified by orthogonal kilovoltage (kV) images, taken before treatment to ensure the accuracy of treatment. The relative localization of the camera based system was verified to be highly accurate along three translational directions of couch motion and couch rotation. After verification, we began treating patients with this technique. About 8-12 properly selected fixed beams with a single isocenter were sufficient to achieve good dose coverage and organ sparing. Portal dosimetry with an Electronic Portal Imaging Device (EPID) and kV images provided excellent quality assurance for the IMRS plan and patient setup. The treatment time was less than 60 min to deliver doses of 16-20 Gy in a single fraction. The camera-based system was verified for positional accuracy and was deemed sufficiently accurate for stereotactic treatments. Single isocenter IMRS treatment of multiple brain metastases or large irregular lesions can be done within an acceptable treatment time and gives the benefits of dose-conformity and organ-sparing, easy plan QA, and patient setup verification.

Image-guided stereotactic spine radiosurgery on a conventional linear accelerator.

Stereotactic radiosurgery for spinal metastasis consists of a high radiation dose delivered to the tumor in 1 to 5 fractions. Due to the high radiation dose in a single or fewer treatments, the precision of tumor localization and dose delivery is of great concern. Many groups have published their experiences of spinal radiosurgery with the use of CyberKnife System (Accuray Inc.). In this study, we report in detail our approach to stereotactic spine radiosurgery (SSRS) using a conventional linear accelerator (Varian Trilogy), utilizing the features of kilovolt on-board imaging (kV-OBI) and cone beam computed tomography (CBCT) for image guidance. We present our experience in various aspects of the SSRS procedure, including patient simulation and immobilization, intensity-modulated radiation treatment (IMRT) planning and beam selection, portal dosimetry for patient planning quality assurance (QA), and the use of image guidance in tumor localization prior to and during treatment delivery.

Dosimetric comparison of intensity-modulated radiosurgery and helical tomotherapy for the treatment of multiple intracranial metastases.

The purpose of this study was to evaluate the dosimetry of single fraction, single-isocenter intensity-modulated radiosurgery (IMRS) plans for multiple intracranial metastases and to compare Helical Tomotherapy (HT). Ten treatment plans with 3-6 brain metastases treated with IMRS were re-planned with HT. The mean number of lesions was 5 and mean PTV 22 cm(3). The prescribed dose was 16-20 Gy. The mean V100% was similar for IMRS and HT, and the mean conformity index was 1.4, mean Paddick confirmity index was 0.7, and mean MDPD was 1.1 for both. The mean gradient index was similar for both. The mean 50% _isodose volume was 179.2 cm(3) for IMRS and 277.0 cm(3) for HT (p=0.01). The mean maximum doses to organs at risk were lower for IMRS except brainstem and right optic nerve. For brain, the integral dose was 5.1 and 6.8 Gy-kg (p<0.001) and mean dose 4.0 and 5.4 Gy (p<0.001) for IMRS and HT, respectively. The mean treatment times were 23 (IMRS) and 41 (HT) minutes. Conformity and homogeneity indices were equivalent and sparing of the organs at risk was clinically acceptable for both IMRS and HT. Though the gradient index was similar for IMRS and HT, the mean 50% isodose volume and integral dose to normal brain were lower for IMRS as was treatment time.

Prostate bed localization with image-guided approach using on-board imaging: reporting acute toxicity and implications for radiation therapy planning following prostatectomy.

OBJECTIVES: To report our experience using Image-Guided Radiation Therapy (IGRT) in patients undergoing post-prostatectomy irradiation. METHODS: Twenty-six patients were treated with radiotherapy following radical prostatectomy using Intensity Modulated Radiation Therapy (IMRT). Prostate bed localization was done using image guidance to align surgical clips relative to the reference isocenter on the planning digitally reconstructed radiographs. Assuming surgical clips to be surrogate for prostate bed, daily shifts in their position were calculated after aligning with the bony anatomy. Shifts were recorded in three dimensions. The acute toxicity was measured during and after completion of treatment. RESULTS: The average (standard deviation) prostate bed motion in anterior-posterior, superior-inferior and left-right directions were: 2.7mm (2.1), 2.4mm (2.1) and 1.0mm (1.7), respectively. The majority of patients experienced only grade 1 symptoms, two patients had grade 2 symptoms and none had grade 3 or higher acute toxicity. CONCLUSIONS: Daily IGRT is recommended for accurate target localization during radiation delivery to improve efficacy of treatment and enhance therapeutic ratio. Larger studies with longer follow-up are necessary to make definitive recommendations regarding magnitude of margin reduction around clinical target volume.