Multicenter Study of Pelvic Nodal Autosegmentation Algorithm of Siemens Healthineers: Comparison of Male Versus Female Pelvis.

Purpose: The autosegmentation algorithm of Siemens Healthineers version VA 30 (AASH) (Siemens Healthineers, Erlangen, Germany) was trained and developed in the male pelvis, with no published data on its usability in the female pelvis. This is the first multi-institutional study to describe and evaluate an artificial intelligence algorithm for autosegmentation of the pelvic nodal region by gender. Methods and Materials: We retrospectively evaluated AASH pelvic nodal autosegmentation in both male and female patients treated at our network of institutions. The automated pelvic nodal contours generated by AASH were evaluated by 1 board-certified radiation oncologist. A 4-point scale was used for each nodal region contour: a score of 4 is clinically usable with minimal edits; a score of 3 requires minor edits (missing nodal contour region, cutting through vessels, or including bowel loops) in 3 or fewer computed tomography slices; a score of 2 requires major edits, as previously defined but in 4 or more computed tomography slices; and a score of 1 requires complete recontouring of the region. Pelvic nodal regions included the right and left side of the common iliac, external iliac, internal iliac, obturator, and midline presacral nodes. In addition, patients were graded based on their lowest nodal contour score. Statistical analysis was performed using Fisher exact tests and Yates-corrected χ2 tests. Results: Fifty-two female and 51 male patients were included in the study, representing a total of 468 and 447 pelvic nodal regions, respectively. Ninety-six percent and 99% of contours required minor edits at most (score of 3 or 4) for female and male patients, respectively (P = .004 using Fisher exact test; P = .007 using Yates correction). No nodal regions had a statistically significant difference in scores between female and male patients. The percentage of patients requiring no more than minor edits was 87% (45 patients) and 92% (47 patients) for female and male patients, respectively (P = .53 using Fisher exact test; P = .55 using Yates correction). Conclusions: AASH pelvic nodal autosegmentation performed very well in both male and female pelvic nodal regions, although with better male pelvic nodal autosegmentation. As autosegmentation becomes more widespread, it may be important to have equal representation from all sexes in training and validation of autosegmentation algorithms.

Stereotactic radiosurgery in India: A nationwide survey of technology and quality assurance practices.

PURPOSE: India is rapidly adopting advanced treatments like Stereotactic Radiosurgery (SRS). However, there is a paucity of data on SRS practice. The aim of study is to assess the current status of technology and practices of machine quality assurance (QA) and patient specific quality assurance for SRS in India. MATERIALS AND METHODS: A survey questionnaire was designed using Google Forms and sent to chief/senior medical physicists across 220 radiotherapy centers in India on July 15, 2022. It contained questions on infrastructure availability, treatment planning, and QA. RESULTS: SRS was found to be extensively used for the treatment of brain metastases (99.3%), followed by meningioma (50.3%), acoustic neuroma (45.5%), and pituitary tumours (33.1%). The most commonly used photon energy and treatment technique were 6MV FFF and VMAT, respectively. A prescription isodose line ranging from 70% to 100% was selected by linac users. Most linac institutes verify pretreatment doses. There was a lack of uniformity in the analysis metrics such as Low Dose Threshold, Dose Difference, and Distance to Agreement. A survey revealed that the variety of SRS QA programs being followed at Indian radiotherapy centers. CONCLUSION: This is the first study to report the physics practice of SRS in India. The survey shows a need to carry out a postal dose audit for small static photon fields in India.

Influence of conservation agriculture-based production systems on bacterial diversity and soil quality in rice-wheat-greengram cropping system in eastern Indo-Gangetic Plains of India.

Introduction: Conservation agriculture (CA) is gaining attention in the South Asia as an environmentally benign and sustainable food production system. The knowledge of the soil bacterial community composition along with other soil properties is essential for evaluating the CA-based management practices for achieving the soil environment sustainability and climate resilience in the rice-wheat-greengram system. The long-term effects of CA-based tillage-cum-crop establishment (TCE) methods on earthworm population, soil parameters as well as microbial diversity have not been well studied. Methods: Seven treatments (or scenarios) were laid down with the various tillage (wet, dry, or zero-tillage), establishment method (direct-or drill-seeding or transplantation) and residue management practices (mixed with the soil or kept on the soil surface). The soil samples were collected after 7 years of experimentation and analyzed for the soil quality and bacterial diversity to examine the effect of tillage-cum-crop establishment methods. Results and Discussion: Earthworm population (3.6 times), soil organic carbon (11.94%), macro (NPK) (14.50-23.57%) and micronutrients (Mn, and Cu) (13.25 and 29.57%) contents were appreciably higher under CA-based TCE methods than tillage-intensive farming practices. Significantly higher number of OTUs (1,192 ± 50) and Chao1 (1415.65 ± 14.34) values were observed in partial CA-based production system (p ≤ 0.05). Forty-two (42) bacterial phyla were identified across the scenarios, and Proteobacteria, Actinobacteria, and Firmicutes were the most dominant in all the scenarios. The CA-based scenarios harbor a high abundance of Proteobacteria (2-13%), whereas the conventional tillage-based scenarios were dominated by the bacterial phyla Acidobacteria and Chloroflexi and found statistically differed among the scenarios (p ≤ 0.05). Composition of the major phyla, i.e., Proteobacteria, Actinobacteria, and Firmicutes were associated differently with either CA or farmers-based tillage management practices. Overall, the present study indicates the importance of CA-based tillage-cum-crop establishment methods in shaping the bacterial diversity, earthworms population, soil organic carbon, and plant nutrient availability, which are crucial for sustainable agricultural production and resilience in agro-ecosystem.

Multi-institutional dose audit in radiotherapy facilities using in-house developed optically stimulated luminescence disc dosimeters.

Aim: The aim of this study was to carried out the audit of radiotherapy centers practicing conformal radiotherapy techniques and demonstrate the suitability of this indigenous optically stimulated luminescence (OSL) disc dosimeters in beam quality audit and verification of patient-specific dosimetry in conventional and conformal treatments in radiotherapy. Materials and Methods: Dose audit in conventional and conformal (intensity-modulated radiotherapy and volumetric-modulated arc therapy) radiotherapy techniques was conducted using in-house developed Al2O3:C-based OSL disc dosimeter and commercially available Gafchromic EBT3 film in 6 MV (flat and unflat) photon and 6 and 15 MeV electron beams. OSL disc dosimeter and Gafchromic EBT3 film measured dose values were verified using the ionization chamber measurements. Results: Percentage variations of doses measured by OSL disc dosimeters and EBT3 Gafchromic film for conventional radiotherapy technique were in the range of 0.15%-4.6% and 0.40%-5.45%, respectively, with respect to the treatment planning system calculated dose values. For conformal radiotherapy techniques, the percentage variations of OSL disc and EBT3 film measured doses were in the range of 0.1%-4.9% and 0.3%-5.0%, respectively. Conclusion: The results of this study supported by statistical evidence provided the confidence that indigenously developed Al2O3:C-based OSL disc dosimeters are suitable for dose audit in conventional and advanced radiotherapy techniques.

Deficiency of phyto-available sulphur, zinc, boron, iron, copper and manganese in soils of India.

Nutrient deficiencies in soil-crop contexts and inappropriate managements are the important reasons for low crop productivity, reduced nutritional quality of agricultural produce and animal/human malnutrition, across the world. The present investigation was carried out to evaluate nutrient deficiencies of sulphur (S) and micronutrients [zinc (Zn), boron (B), iron (Fe), copper (Cu) and manganese (Mn)] in agricultural soils of India for devising effective management strategies to achieve sustainable crop production, improved nutritional quality in crops and better animal/human health. A total of 2,42,827 surface (0-15 cm depth) soil samples were collected from agriculture fields of 615 districts lying in 28 states of India and were analysed for available S and micronutrients concentration. The study was carried out under the aegis of All India Coordinated Research Project on Micro- and Secondary-Nutrients and Pollutant Elements in Soils and Plants. The mean concentrations were 27.0 ± 29.9 mg kg-1 for available S, 1.40 ± 1.60 mg kg-1 for available Zn and 1.40 ± 4.70 mg kg-1 for available B, 31.0 ± 52.2 mg kg-1 for available Fe, 2.30 ± 3.50 mg kg-1 for available Cu and 17.5 ± 21.4 mg kg-1 for available Mn. There were variable and widespread deficiencies of S and micronutrients in different states. The deficiencies (acute deficient + deficient + latent deficiency) of S (58.6% of soils), Zn (51.2% of soils) and B (44.7% of soils) were higher compared to the deficiencies of Fe (19.2% of soils), Cu (11.4% of soils) and Mn (17.4% of soils). Out of 615 districts, > 50% of soils in 101, 131 and 86 districts were deficient in available S, available Zn and available B, respectively. Whereas, > 25% of soils in 83, 5 and 41 districts had deficiencies of available Fe, available Cu and available Mn, respectively. There were occurrences of 2-nutrients deficiencies such S + Zn (9.30% of soils), Zn + B (8.70% of soils), S + B (7.00% of soils) and Zn + Fe (5.80% of soils) to a greater extent compared to the deficiencies of Zn + Mn (3.40% of soils), S + Fe (3.30% of soils), Zn + Cu (2.80% of soils) and Fe + B (2.70% of soils). Relatively lower % of soils were deficient in 3-nutrients (namely S + Zn + B, S + Zn + B and Zn + Fe + B), 4-nutrients (namely Zn + Fe + Cu + Mn) and 5-nutrients (namely Zn + Fe + Cu + Mn + B) simultaneously. The information regarding the distribution of deficiencies of S and micronutrients (both single and multi-nutrients) could be used by various stakeholders for production, supply and application of right kind of fertilizers in different districts, states and agro-ecological regions of India for better crop production, crop nutritional quality, nutrient use efficiency, soil health and for tackling human and animal malnutrition.

Nitrogen Availability and Use Efficiency in Wheat Crop as Influenced by the Organic-Input Quality Under Major Integrated Nutrient Management Systems.

PURPOSE: One of the serious constraints for the integration of organics in soil fertility plans is the release and availability of nitrogen (N) to match the critical growth stages of a crop. The interplay between organic amendment characteristics and soil moisture conditions can significantly affect the nutrient release and availability, especially for dryland crops like wheat. In this study, the effects of integrated nutrient management strategies using diverse qualities of organic amendments on daily N mineralization and its availability to plants during the full growing season of the wheat crop were analyzed in a 10-year experiment. METHODS: The management included (1) F, inorganic fertilizers at 100% rate, compared to a reduced rate of inorganic fertilizers (55% N) supplemented with organic inputs via (2) GM, green manuring, (3) LE, legume cropping and its biomass recycling, (4) WS, wheat stubble retention, (5) RS, rice stubble retention, and (6) FYM, farmyard manure application, during the preceding rice season. Ion exchange resin (IER) membrane strips were used as plant root simulators to determine daily NH4 +-N and NO3 --N availability in soil solution during the full wheat growing period. RESULTS: Total available N for the full season was in the following order: GM (962 µg cm-2) > F (878 µg cm-2) > LE (872 µg cm-2) > FYM (865 µg cm-2) > RS (687 µg cm-2) > WS (649 µg cm-2). No significant differences were observed in NH4 +-N availability throughout the cropping period as compared to NO3 --N which showed significant differences among management at critical crop growth stages. CONCLUSION: Legume biomass incorporation (GM, LE) and farmyard manure (FYM) based management provided the most consistent supply equivalent to or even exceeding 100% inorganic fertilizers at several critical stages of growth, especially at tillering and stem elongation. Integration of organics in management increased nitrogen use efficiency 1.3-2.0 times, with cereal crop residue-based management having the highest efficiency followed by legume biomass incorporation.

Nitrous oxide production from soybean and maize under the influence of weedicides and zero tillage conservation agriculture.

Current experiment envisages evaluating N2O production from nitrification and denitrification under the influence of weedicides, cropping systems and conservation agriculture (CA). The weed control treatments were conventional hand weeding (no weedicide), pre emergence weedicide pendimethalin and post emergence weedicide imazethapyr for soybean, atrazine for maize. Experiment was laid out in randomized block design with three replicates. Soils were collected from different depths and incubated at different moisture holding capacity (MHC). N2O production from nitrification varied from 2.77 to 6.04 ng N2O g-1 soil d-1 and from denitrification varied from 0.05 to 1.34 ng N2O g-1 soil d-1. Potential nitrification rate (0.16-0.39 mM NO3 produced g-1 soil d-1) was higher than potential denitrification rate (0.45-0.93 mM NO3 reduced g-1 soil d-1). N2O production, nitrification, denitrification, and microbial gene abundance were higher in maize than soybean. Both N2O production and nitrification decreased (p < 0.05) with soil depth, while denitrification increased (p < 0.05) with soil depth. Abundance of eubacteria and ammonia oxidizing bacteria (AOB) were high (p < 0.01) at upper soil layer and declined with depth. Abundance of ammonia oxidizing archaea (AOA) increased (p < 0.05) with soil depth. Study concludes that intensive use of weedicides in CA may stimulate N2O production.

Relative energy response of indigenously developed optically stimulated luminescence dosimeters Al2 O3 :C, LiMgPO4 :B and LiCaAlF6 :Eu,Y in therapeutic photon and electron beams.

The relative energy responses of three indigenously developed optically stimulated luminescence (OSL) phosphors in the disc form were studied in therapeutic photon and electron beams. Calibration in terms of absorbed dose was carried out in the dose range 5-500 cGy in 60 Co gamma rays, high energy X-rays, and electron beams used in radiotherapy. The combined standard uncertainty in the estimation of absorbed dose using these OSL discs (OSLDs) was 3.3%. Dose-response curves of these OSLDs in 60 Co gamma rays, 6 and 10 MV (flat and unflat), 15 MV and 6 and 15 MeV electron beams were found to be linear. Furthermore, these OSLDs exhibited a relative energy-dependent response for both photon and electron beams. The relative energy response correction factor for photon and electron beams were in the range 1.01-1.05 and 1.03-1.06, respectively.

PATIENT-SPECIFIC DOSIMETRY USING IN-HOUSE DEVELOPED OSL DISC DOSEMETERS.

Circular discs of diameter 5 mm were made from three indigenously developed optically stimulated luminescent (OSL) phosphors for medical dosimetry. Dosimetric characteristics of these discs were evaluated for their use in machine and patient-specific dosimetry in radiotherapy. Uncertainty in dosimetric measurements using these discs was also estimated, and combined standard uncertainty in measurement of absorbed dose was found to be 3.34%. Characterisation studies indicate that OSL discs are suitable for dosimetric application in radiotherapy. These discs were also used for patient-specific dosimetry in conventional and conformal radiotherapy treatments (five different cases) vis-à-vis ionisation chamber and Gafchromic EBT3 film. Doses measured by OSL discs were found comparable to ionisation chamber and Gafchromic EBT3 film measured values and radiotherapy treatment planning system (TPS) calculated dose values in all the cases. The variation between TPS calculated dose values and OSL discs measured dose values was found within the measurement uncertainty.

Impact of carbon inputs on soil carbon fractionation, sequestration and biological responses under major nutrient management practices for rice-wheat cropping systems.

Major nutrient management systems for rice-wheat cropping were compared for their potential to credit organic carbon (C) to the soil, its fractionation into active (very labile, VLc; labile, Lc) and passive (less labile, LLc; non-labile, NLc) pools, and crop yield responses. A ten-year long experiment was used to study effects of: (i) no inputs (Control, O), (ii) 100% inorganic fertilizers (F) compared to reduced fertilizers inputs (55%) supplemented with biomass incorporation from (iii) opportunity legume crop (Vigna radiata) (LE), (iv) green manure (Sesbania aculeata) (GM), (v) farmyard manure (FYM), (vi) wheat stubble (WS), and (vii) rice stubble (RS). Maximum C input to soil (as the percentage of C assimilated in the system) was in GM (36%) followed by RS (34%), WS (33%), LE (24%), and FYM (21%) compared to O (15%) and F (15%). Total C input to soil had a direct effect on soil C stock, soil C fractions (maximum in VLc and LLc), yet the responses in terms of biological yield were controlled by the quality of the biomass (C:N ratio, decomposition, etc.) incorporated. Legume-based biomass inputs accrued most benefits for soil C sequestration and biological productivity.

Measurement of Total Scatter Factor for Stereotactic Cones with Plastic Scintillation Detector.

Advanced radiotherapy modalities such as stereotactic radiosurgery (SRS) and image-guided radiotherapy may employ very small beam apertures for accurate localized high dose to target. Accurate measurement of small radiation fields is a well-known challenge for many dosimeters. The purpose of this study was to measure total scatter factors for stereotactic cones with plastic scintillation detector and its comparison against diode detector and theoretical estimates. Measurements were performed on Novalis Tx™ linear accelerator for 6MV SRS beam with stereotactic cones of diameter 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm. The advantage of plastic scintillator detector is in its energy dependence. The total scatter factor was measured in water at the depth of dose maximum. Total scatter factor with plastic scintillation detector was determined by normalizing the readings to field size of 10 cm × 10 cm. To overcome energy dependence of diode detector for the determination of scatter factor with diode detector, daisy chaining method was used. The plastic scintillator detector was calibrated against the ionization chamber, and the reproducibility in the measured doses was found to be within ± 1%. Total scatter factor measured with plastic scintillation detector was 0.728 ± 0.3, 0.783 ± 0.05, 0.866 ± 0.55, 0.885 ± 0.5, and 0.910 ± 0.06 for cone sizes of 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. Total scatter factor measured with diode detector was 0.733 ± 0.03, 0.782 ± 0.02, 0.834 ± 0.07, 0.854 ± 0.02, and 0.872 ± 0.02 for cone sizes of 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. The variation in the measurement of total scatter factor with published Monte Carlo data was found to be -1.3%, 1.9%, -0.4%, and 0.4% for cone sizes of 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. We conclude that total scatter factor measurements for stereotactic cones can be adequately carried out with a plastic scintillation detector. Our results show a high level of consistency within our data and compared well with published data.

High dose chemoradiation for unresectable hilar cholangiocarcinomas using intensity modulated external beam radiotherapy: a single tertiary care centre experience.

BACKGROUND: We present results of patients diagnosed with unresectable hilar cholangiocarcinomas treated with high dose radiotherapy and concurrent chemotherapy. METHODS: From Aug 2005 to Dec 2012, 68 consecutive patients were treated. Fifty patients (group 1) presenting to us with obstructive jaundice were planned for endobiliary brachytherapy (EBBT 14 Gy) followed external beam radiotherapy (EBRT 45 Gy). Twenty-two patients (group 2) who had previously undergone biliary drainage underwent EBRT (57 Gy). All patients received injection Gemcitabine 300 mg/m2/weekly along with EBRT. RESULTS: Twenty-nine patients in group 1 and 22 patients in group 2 completed the treatment. Twenty-six (55%) patients achieved complete radiological response, 16 (64%) belonging to group 1 and 8 (44%) of group 2 (P=0.05). The median overall survival (MOS) was 17.5 and 16 months for group 1 and 2 respectively (P=0.07). The 1- and 2-year survival was 63%, and 18% for group I and 61% and 22% for group II respectively. The MOS was 5 months and 1 year survival was 14% for patients receiving EBBT only. MOS was significantly better after complete response (P=0.001). CONCLUSIONS: Intensity modulated radiotherapy (IMRT) modulated high dose radiotherapy used either alone or with brachytherapy demonstrates potential to prolonged overall survival in unresectable hilar cholangiocarcinomas.

Interobserver Variability in the Delineation of Gross Tumour Volume and Specified Organs-at-risk During IMRT for Head and Neck Cancers and the Impact of FDG-PET/CT on Such Variability at the Primary Site.

PURPOSE: To assess interobserver variability (IOV) in the delineation of structures during intensity-modulated radiation therapy for head and neck squamous cell carcinoma and the impact of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on such variability at the primary site. METHODS: Three experienced head-neck radiation oncologists, blinded to each other, delineated the primary site gross tumour volume (GTV) and specified organs-at-risk (OARs) viz parotid gland, spinal cord, and cochlea in 10 patients with pharyngolaryngeal cancers suited for definitive intensity-modulated radiation therapy. IOV was assessed by concordance index (CI), Dice similarity coefficient (DSC), and Fleiss' kappa. Subsequently, the observers refined their corresponding GTVs incorporating information from FDG-PET/CT. The impact of FDG-PET/CT on variability of GTV was assessed by comparing the overlap indices with and without FDG-PET/CT using paired 't' test. RESULTS: There was moderate IOV in the delineation of GTV as evidenced by mean CI, DSC, and Fleiss' kappa of 0.41, 0.57, and 0.56, respectively. The use of FDG-PET/CT improved consistency of target volume delineation with resultant improvement in the overlap indices (mean CI, DSC, and Fleiss' kappa of 0.54, 0.69, and 0.69, respectively) that was statistically significant (P < .001). There was good agreement between the three observers for delineation of spinal cord and parotid glands. Concordance was worst for the cochlea. CONCLUSION: This study demonstrates the presence of moderate IOV between three experienced head and neck radiation oncologists in an academic institutional setting for the delineation of GTV. The use of FDG-PET/CT for target volume delineation results in significant reduction of such variability.

Volume changes with stereotactic body radiation therapy in early lung cancer: Time trends and outcomes.

INTRODUCTION: Tumour response during stereotactic body radiotherapy (SBRT) could be heterogeneous and the pattern of response may be used as an early predictor for outcome. METHODS: Twenty-two consecutive patients with early lung cancer (ELC), treated with SBRT, were evaluated retrospectively for their gross tumour volume (GTV) changes during radiation therapy (RT). Kilo-voltage computed tomography scans (KVCTs) were acquired before every fraction and GTV was contoured manually on a total of 152 datasets. Tumour volume changes were noted with every fraction. The overall survival (OS), locoregional recurrence free survival (LRFS) and distant metastasis free survival (DMFS) were computed using the Kaplan-Meier method and comparisons were made using log-rank test. RESULTS: Of the 22 patients, six had T1 tumours and 16 had T2 tumours. Median GTV was 40.6 cc (range 7.3-140.2 cc) on CT1 (KVCT at first fraction) and 33.3 cc (range 4.1-83.4 cc) on CTlast (KVCT at last fraction), suggesting a 17.9% median volume reduction at RT completion. Increase in tumour volume was noted in 18 (81.8%) patients at some point during RT. In the mid-treatment scan, 12 (54.5%) patients had higher tumour volumes than in CT1, however, only six (27.3%) patient's GTV remained larger compared to the baseline at the end of treatment. The median follow-up was 12.4 months. The OS, LRFS and DMFS rate at 12 and 18 months were 86.4%, 88.2%, 62% and 64.8%, 75.6% and 37.2% respectively. Tumours that regressed in volume by >17.9% (median volume reduction at RT completion) had significantly worse OS and LRFS compared to those that regressed <17.9% (P = 0.03 and 0.01 respectively). CONCLUSION: Gross tumour volume undergoes significant changes during SBRT. Early regression in tumour volume may be used as a predictor of poor LRFS and OS.

Superficial ocular malignancies treated with strontium-90 brachytherapy: long term outcomes.

PURPOSE: The incidence of conjunctival malignancies is less than 1%. Though surgical excision remains the mainstay of treatment, the incidence of positive surgical margins and local recurrence rates are high, which is approximately up to 33% in negative margins and 56% in positive margins. Radiotherapy reduces the risk of recurrence in these cases. Brachytherapy using ß emitters such as strontium-90 ((90)Sr) is an ideal treatment technique for these tumors with the advantage of treating only a few millimeters of tissue while sparing the underlying normal eye. We report the long term outcomes in the form of local control and late sequelae of patients with conjunctival malignancies treated with (90)Sr applicator brachytherapy. MATERIAL AND METHODS: During 1999-2013, 13 patients with conjunctival tumors, treated using (90)Sr brachytherapy were analyzed. Brachytherapy was either in a post-operative adjuvant or in a recurrent setting. Local control (LC), disease free survival (DFS), overall survival (OS), and late sequelae were evaluated. RESULTS: The median age at presentation was 47 years (range: 11-71 years). Thirteen patients with 15 tumors were treated. The commonest histology was squamous cell carcinoma. The median dose was 44 Gy over 11 fractions. The median follow up of all the patients was 51 months (range: 3-139 months). The median follow up of patients with carcinoma only was 64 months with a LC and DFS of 90.9% at 5 years. None of the patients developed ≥ grade II Radiation Therapy Oncology Group (RTOG) acute toxicities. One patient developed a focal scar and another developed corneal opacification at the limbus. Vision was not impaired in any of the patients. CONCLUSIONS: Strontium-90 brachytherapy used in early invasive conjunctival malignancies as an adjunct to surgery in primary and recurrent settings, results in optimal disease control and ocular functional outcomes.

Adaptive radiation therapy for pediatric head and neck malignancies: Dosimetric implications.

PURPOSE: This study was designed to evaluate the role of adaptive radiation therapy for children receiving curative radiation therapy to the head and neck region. METHODS AND MATERIALS: Ten children receiving definitive, conformal radiation therapy to the head and neck region were prospectively evaluated for anatomic changes during the course of radiation therapy. Images were acquired midway through the number of planned radiation therapy fractions during the planned course of radiation therapy. Body contours, target volumes, and organs at risk were redrawn on the new set of images. Two sets of additional treatment plans were generated: (1) a nonoptimized plan (plan 2), that is, an overlay of the original plan (plan 1) on the new set of contours, and (2) an optimized plan (plan 3) with the new set of contours. These 3 sets of plans were then compared for dosimetric differences. RESULTS: Five children had nasopharynx carcinoma, whereas the other 5 had embryonal rhabdomyosarcoma. The average reduction in gross tumor volume was 40% (mean volume, 41.87 mL; P = .005). The average changes in right and left parotid volumes were 2.72 and 1.92 mL, respectively. With nonoptimized plans, the average increase in maximum dose to the spinal cord was 15% (79.99%-94.99%; P = .013). With reoptimization, the maximum dose to the spinal cord decreased from 94.99% to 85.26% (mean difference, -9.73%; P = .02). Average D99 for the planning target volume (dose received by 99% of the target volume) was 88.66% and 86.89% with the original and reoptimized plans, respectively (P = .50). For the entire group, the mean conformation number index with nonoptimized plans was reduced from 0.734 to 0.628 (P = .013). This improved with reoptimization (P = .114). The homogeneity index improved with reoptimization from a mean value of 0.113 to 0.098 (P = 0.28). For nonoptimized plans, the average integral dose increased from 74.66 to 76.27 L-Gy (P = .486) compared with the original plans. Reoptimization resulted in a 5% average reduction in the integral dose, from 76.27 to 72.28 L-Gy (P = .007). CONCLUSIONS: This study demonstrates the usefulness of adaptive radiation therapy for children receiving radiation therapy to the head and neck region.

Comparison of 2 contouring methods of bone marrow on CT and correlation with hematological toxicities in non-bone marrow-sparing pelvic intensity-modulated radiotherapy with concurrent cisplatin for cervical cancer.

OBJECTIVES: To compare volumes and dose volume histogram (DVH) parameters for bone marrow contours using 2 methods on computed tomography (CT) and correlation with grade 2 or higher hematological toxicity (HT) in patients with cervical cancer treated with non-bone marrow-sparing intensity-modulated radiotherapy (IMRT) with concurrent cisplatin. MATERIALS AND METHODS: The planning CT scans of 47 patients prospectively enrolled and treated with IMRT arm of a phase 2 trial (NCT00193804) contoured for pelvic bone marrow in 2 sets; whole bone (WB), and freehand (FH) inner cavity of bone. Various subvolumes were made in each set--sacrum, ilium, ischium, lower pelvis, lumbosacral spine, sacrum, and whole pelvis--and compared for volume and DVH parameters (V(10), V(20), V(30), and V(40)) using paired t test. The hematological parameters during RT compiled from electronic database analyzed for higher than grade 2 (Radiation Therapy Oncology Group) HT and correlated with DVH parameters using log regression analysis (P < 0.05 significant). RESULTS: The FH subvolumes were 25% to 30% of WB. The mean DVH parameters V(10), V(20), V(30), and V(40) for whole-pelvis FH and WB were 86.5%, 77.5%, 62.5%, and 40.5%; and 88%, 79.6%, 62.9%, and 40%, respectively. There was significant difference between the DVH parameters of 2 sets (P < 0.05) for all subvolumes except ischium V(20), sacrum V(10), and lumbosacral spine V(10). The leukopenia, neutropenia, anemia, and thrombocytopenia higher than grade 2 was seen in 53%, 29.8%, 65.9%, and 10.6%, respectively. The mean V(10) for whole pelvis was less than 90% for both sets. On both univariate and multivariate analyses, only FH whole pelvis V(40) more than or equal to 40% correlated with higher than grade 2 leukopenia (Mann-Whitney U test, P = 0.026) and neutropenia (P = 0.05) with odds ratio, 4 (95% confidence interval, 1.166-13.728; P = 0.028). CONCLUSIONS: The FH bone marrow cavity volume is a better surrogate of active bone marrow on CT images and correlated with higher than grade 2 HT (V(40) >40%). Further prospective studies validating significance of high-dose effects and identifying correlation of bioimaging with CT contouring are warranted.