Technical recommendations for implementation of Volumetric Modulated Arc Therapy and Helical Tomotherapy Total Body Irradiation.

As a component of myeloablative conditioning before allogeneic hematopoietic stem cell transplantation (HSCT), Total Body Irradiation (TBI) is employed in radiotherapy centers all over the world. In recent and coming years, many centers are changing their technical setup from a conventional TBI technique to multi-isocenter conformal arc therapy techniques such as Volumetric Modulated Arc Therapy (VMAT) or Helical Tomotherapy (HT). These techniques allow better homogeneity and control of the target prescription dose, and provide more freedom for individualized organ-at-risk sparing. The technical design of multi-isocenter/multi-plan conformal TBI is complex and should be developed carefully. A group of early adopters with conformal TBI experience using different treatment machines and treatment planning systems came together to develop technical recommendations and share experiences, in order to assist departments wishing to implement conformal TBI, and to provide ideas for standardization of practices.

Periodontal Disease Augments Cardiovascular Disease Risk Biomarkers in Rheumatoid Arthritis.

Objectives: Periodontal disease (PD) and rheumatoid arthritis (RA) are known chronic conditions with sustained inflammation leading to osteolysis. Cardiovascular diseases (CVD) are frequent comorbidities that may arise from sustained inflammation associated with both PD and RA. In order to determine CVD risk, alterations at the molecular level need to be identified. The objective of this study, therefore, was to assess the relationship of CVD associated biomarkers in RA patients and how it is influenced by PD. Methods: The study consisted of patient (26 RA with PD, 21 RA without PD, 51 patients with PD only) and systemically and periodontally healthy control (n = 20) groups. Periodontal parameters bleeding on probing, probing pocket depth, and marginal bone loss were determined to characterize the patient groups. Proteomic analysis of 92 CVD-related protein biomarkers was performed using a multiplex proximity extension assay. Biomarkers were clustered using the search tool for retrieval of interacting genes (STRING) to determine protein−protein interaction (PPI) networks. Results: RA patients with PD had higher detection levels for 47% of the measured markers (ANGPT1, BOC, CCL17, CCL3, CD4, CD84, CTRC, FGF-21, FGF-23, GLO1, HAOX1, HB-EGF, hOSCAR, HSP 27, IL16, IL-17D, IL18, IL-27, IL6, LEP, LPL, MERTK, MMP12, MMP7, NEMO, PAPPA, PAR-1, PARP-1, PD-L2, PGF, PIgR, PRELP, RAGE, SCF, SLAMF7, SRC, THBS2, THPO, TNFRSF13B, TRAIL-R2, VEGFD, VSIG2, and XCL1) as compared to RA without PD. Furthermore, a strong biological network was identified amongst these proteins (clustering coefficient = 0.52, PPI enrichment p-value < 0.0001). Coefficients for protein clusters involved in CVD (0.59), metabolic (0.53), and skeletal (0.51) diseases were strongest in the PD group. Conclusion: Periodontal disease augments CVD-related biomarkers in RA through shared pathological clusters, concurrently enhancing metabolic and skeletal disease protein interactions, independent of autoimmune status.

The last will: Estate divisions as a testament of to whom altruism is directed.

We use data on estate divisions to study to whom altruistic preferences are directed. Insofar bequests are given without the prospect of future personal benefits in mind, they are presumably intrinsically motivated. Hence, estate divisions provide a rare opportunity to study intrinsically motivated prosocial behavior in the field. The empirical analysis is based on data from digitized estate reports for all individuals in Sweden who passed away in 2002 and 2003. The data show in detail how the decedents distributed their bequests. We find that family members, both genetic (offspring) and non-genetic (partner), receive the lion's share of the estates. Other relatives, friends and strangers (represented by charities) receive only very small shares of the total estate wealth. The results suggest that intrinsically motivated altruism is primarily directed towards close family members.

Organ sparing total marrow irradiation compared to total body irradiation prior to allogeneic stem cell transplantation.

OBJECTIVES: Total body irradiation (TBI) is commonly used prior to hematopoietic stem cell transplantation (HSCT) in myeloablative conditioning regimens. However, TBI may be replaced by total marrow irradiation (TMI) at centres with access to Helical TomoTherapy, a modality that has the advantage of delivering intensity-modulated radiotherapy to long targets such as the entire bone marrow compartment. Toxicity after organ sparing TMI prior to HSCT has not previously been reported compared to TBI or with regard to engraftment data. METHODS: We conducted a prospective observational study on 37 patients that received organ sparing TMI prior to HSCT and compared this cohort to retrospective data on 33 patients that received TBI prior to HSCT. RESULTS: The 1-year graft-versus-host disease-free, relapse-free survival (GRFS) was 67.5% for all patients treated with TMI and 80.5% for patients with matched unrelated donor and treated with TMI, which was a significant difference from historical data on TBI patients with a hazard ratio of 0.45 (P = .03) and 0.24 (P < .01). Engraftment with a platelet count over 20 [K/µL] and 50 [K/µL] was significantly shorter for the TMI group, and neutrophil recovery was satisfactory in both treatment cohorts. There was generally a low occurrence of other treatment-related toxicities. CONCLUSIONS: Despite small cohorts, some significant differences were found; TMI as part of the myeloablative conditioning yields a high 1-year GRFS, fast and robust engraftment, and low occurrence of acute toxicity.

ARTSCAN III: A Randomized Phase III Study Comparing Chemoradiotherapy With Cisplatin Versus Cetuximab in Patients With Locoregionally Advanced Head and Neck Squamous Cell Cancer.

PURPOSE: We performed an open-label randomized controlled phase III study comparing treatment outcome and toxicity between radiotherapy (RT) with concomitant cisplatin versus concomitant cetuximab in patients with locoregionally advanced head and neck squamous cell carcinoma (HNSCC; stage III-IV according to the Union for International Cancer Control TNM classification, 7th edition). MATERIALS AND METHODS: Eligible patients were randomly assigned 1:1 to receive either intravenous cetuximab 400 mg/m2 1 week before start of RT followed by 250 mg/m2/wk, or weekly intravenous cisplatin 40 mg/m2, during RT. RT was conventionally fractionated. Patients with T3-T4 tumors underwent a second random assignment 1:1 between standard RT dose 68.0 Gy to the primary tumor or dose escalation to 73.1 Gy. Primary end point was overall survival (OS) evaluated using adjusted Cox regression analysis. Secondary end points were locoregional control, local control with dose-escalated RT, pattern of failure, and adverse effects. RESULTS: Study inclusion was prematurely closed after an unplanned interim analysis when 298 patients had been randomly assigned. At 3 years, OS was 88% (95% CI, 83% to 94%) and 78% (95% CI, 71% to 85%) in the cisplatin and cetuximab groups, respectively (adjusted hazard ratio, 1.63; 95% CI, 0.93 to 2.86; P = .086). The cumulative incidence of locoregional failures at 3 years was 23% (95% CI, 16% to 31%) compared with 9% (95% CI, 4% to 14%) in the cetuximab versus the cisplatin group (Gray's test P = .0036). The cumulative incidence of distant failures did not differ between the treatment groups. Dose escalation in T3-T4 tumors did not increase local control. CONCLUSION: Cetuximab is inferior to cisplatin regarding locoregional control for concomitant treatment with RT in patients with locoregionally advanced HNSCC. Additional studies are needed to identify possible subgroups that still may benefit from concomitant cetuximab treatment.

Surface-guided tomotherapy improves positioning and reduces treatment time: A retrospective analysis of 16 835 treatment fractions.

PURPOSE: In this study, we have quantified the setup deviation and time gain when using fast surface scanning for daily setup/positioning with weekly megavoltage computed tomography (MVCT) and compared it to daily MVCT. METHODS: A total of 16 835 treatment fractions were analyzed, treated, and positioned using our TomoTherapy HD (Accuray Inc., Madison, USA) installed with a Sentinel optical surface scanning system (C-RAD Positioning AB, Uppsala, Sweden). Patients were positioned using in-room lasers, surface scanning and MVCT for the first three fractions. For the remaining fractions, in-room laser was used for setup followed by daily surface scanning with MVCT once weekly. The three-dimensional (3D) setup correction for surface scanning was evaluated from the registration between MVCT and the planning CT. The setup correction vector for the in-room lasers was assessed from the surface scanning and the MVCT to planning CT registration. The imaging time was evaluated as the time from imaging start to beam-on. RESULTS: We analyzed 894 TomoTherapy treatment plans from 2012 to 2018. Of all the treatment fractions performed with surface scanning, 90 % of the residual errors were within 2.3 mm for CNS (N = 284), 2.9 mm for H&N (N = 254), 8.7 mm for thorax (N = 144) and 10.9 for abdomen (N = 134) patients. The difference in residual error between surface scanning and positioning with in-room lasers was significant (P < 0.005) for all sites. The imaging time was assessed as total imaging time per treatment plan, modality, and treatment site and found that surface scanning significantly reduced patient on-couch time compared to MVCT for all treatment sites (P < 0.005). CONCLUSIONS: The results indicate that daily surface scanning with weekly MVCT can be used with the current target margins for H&N, CNS, and thorax, with reduced imaging time.

Upregulation of circulating inflammatory biomarkers under the influence of periodontal disease in rheumatoid arthritis patients.

OBJECTIVES: Periodontal disease (PD) and rheumatoid arthritis (RA) are chronic immuno-inflammatory conditions with osteolysis being a hallmark feature. The influence of PD on RA's systemic inflammatory status and disease activity remains unclear. The objective of this study was to assess the systemic inflammation and disease activity of RA under the influence of PD. METHODS: In this case-control study, 38 RA patients (19 with PD and 19 without PD) were compared to 38 non-RA patients and 12 healthy controls. Periodontal parameters (bleeding on probing (BOP), probing pocket depth (PPD), PPD Total, PPD Disease and marginal bone loss (MBL) were determined. Serological analyses included quantification of 92 inflammatory biomarkers using a multiplex proximity extension assay, anti-citrullinated protein antibodies (ACPA), rheumatoid factor (IgM-RF) and erythrocyte sedimentation rate (ESR). RA disease activity was determined using Disease Activity Score for 28 joints (DAS28). All RA patients were on medication. RESULTS: IgM-RF was higher in RA patients with PD. PD conditions were more severe in the non-RA group. Inflammatory biomarkers (IL-10RB, IL-18, CSF-1, NT-3, TRAIL, PD-L1, LIF-R, SLAMF1, FGF-19, TRANCE, CST5, STAMPB, SIRT2, TWEAK, CX3CL1, CXCL5, MCP-1) were significantly higher in RA patients with PD than RA without PD. DAS28 associated with twice as many inflammatory biomarkers in RA patients with PD whereas IgM-RF and ACPA associated more frequently with biomarkers in the RA without PD group. IgM-RF correlated inversely with BOP. CONCLUSION: Periodontal disease augments systemic inflammation in RA. A profound influence exists independent of autoimmune status.

A Helical tomotherapy as a robust low-dose treatment alternative for total skin irradiation.

Mycosis fungoides is a disease with manifestation of the skin that has traditionally been treated with electron therapy. In this paper, we present a method of treating the entire skin with megavoltage photons using helical tomotherapy (HT), verified through a phantom study and clinical dosimetric data from our first two treated patients. A whole body phantom was fitted with a wetsuit as bolus, and scanned with computer tomography. We accounted for variations in daily setup using virtual bolus in the treatment plan optimization. Positioning robustness was tested by moving the phantom, and recalculating the dose at different positions. Patient treatments were verified with in vivo film dosimetry and dose reconstruction from daily imaging. Reconstruction of the actual delivered dose to the patients showed similar target dose as the robustness test of the phantom shifted 10 mm in all directions, indicating an appropriate approximation of the anticipated setup variation. In vivo film measurements agreed well with the calculated dose confirming the choice of both virtual and physical bolus parameters. Despite the complexity of the treatment, HT was shown to be a robust and feasible technique for total skin irradiation. We believe that this technique can provide a viable option for Tomotherapy centers without electron beam capability.

Implementing safe and robust Total Marrow Irradiation using Helical Tomotherapy - A practical guide.

Total Marrow Irradiation (TMI) with Helical Tomotherapy is a radiotherapy treatment technique that targets bone marrow and sanctuary sites prior to stem cell or bone marrow transplantation (SCT/BMT). TMI is a complex procedure that involves several critical steps that all need to be carefully addressed for a successful implementation, such as dose homogeneity in field junctions, choice of target margins, integrity of treatment and back-up planning. In this work we present our solution for a robust and reproducible workflow throughout the treatment chain and data for twenty-three patients treated to date. MATERIAL & METHODS: Patients were immobilized in a whole body vacuum cushion and thermoplastic mask. CT-scanning and treatment were performed in two parts with field matching at the upper thigh. Target consisted of marrow containing bone and sanctuary sites. Lungs, kidneys, bowel, heart and liver were defined as organs at risk (OAR). A fast surface scanning system was used to position parts of the body not covered by the imaging system (MVCT) as well as to reduce treatment time. RESULTS: All patients completed their treatment and could proceed with SCT/BMT. Doses to OARs were significantly reduced and target dose homogeneity was improved compared to TBI. Robustness tests performed on field matching and patient positioning support that the field junction technique is adequate. Replacing MVCT with optical surface scanning reduced the treatment time by 25 min per fraction. CONCLUSION: The methodology presented here has shown to provide a safe, robust and reproducible treatment for Total Marrow Irradiation using Tomotherapy.

Periodontal disease influences osteoclastogenic bone markers in subjects with and without rheumatoid arthritis.

BACKGROUND: Periodontal disease (PD) and rheumatoid arthritis (RA) are bone pathologies mediated through immuno-inflammatory mechanisms. The aim of this study was to investigate the serum markers osteopontin (OPN), tumor necrosis factor receptors 1 (TNFR1) and 2 (TNFR2) receptor activator of nuclear factor-kappa B ligand (RANKL) and RANKL/ osteoprotegerin (OPG) ratio and compare them in PD and RA groups. MATERIALS & METHODS: RA (with PD = 19 and without PD = 19), PD (n = 38) and 14 healthy subjects underwent bleeding on probing (BOP) and probing pocket depth (PPD) measurement. PD was defined as PPD measuring ≥5mm registered in ≥3 sites. Marginal bone loss (MBL) for premolars and molars was measured on digital panoramic radiographs. Serum samples were collected from all subjects. OPN, TNFR1, TNFR2 and RANKL were measured by enzyme-linked immunosorbent assays (ELISAs). OPG was measured as part of a multiplex proximity extension assay (PEA). RESULTS: OPN, TNFR1, TNFR2 and RANKL serum levels were the highest in the RA group with PD, while the RA group without PD were comparable to PD subjects only. The RANKL/OPG ratios were comparable between PD group and both RA groups with (p = 0.051) and without PD (p = 0.37). Serum RANKL levels were associated with MBL (p = 0.008) and PPD ≥ 5mm (p = 0.01). CONCLUSION: Peripheral osteoclastogenesis is a feature of periodontal disease with systemic levels of osteoclastogenic markers comparable to the effects observed in rheumatoid arthritis.

Correlation of serum cytokines, chemokines, growth factors and enzymes with periodontal disease parameters.

BACKGROUND: Periodontal disease (PD) is characterized by inflammatory tissue destruction in tooth supporting apparatus. Many studies indicate that the underlying pathogenesis is in concordance with rheumatoid arthritis (RA) sharing immune-inflammatory events affect both diseases. The aim of this study was to investigate serum cytokines, chemokines, growth factors, enzymes and costimulatory proteins in association with periodontal conditions in PD and RA subjects. MATERIALS & METHODS: Periodontal examination was performed in RA (n = 38), PD (n = 38) and healthy subjects (n = 14). Bleeding on probing (BOP) and probing pocket depth (PPD) were measured. Marginal bone loss (MBL) for premolars and molars was measured on digital panoramic radiographs. PD was defined as present if the PPD was ≥5mm in ≥ 3 different sites. Serum samples were collected from all subjects. A multiplex proximity extension assay (PEA) was used to analyze the samples for simultaneous measurement of 92 cytokines. Cytokines with ≥ 60% quantitative results were included. RESULTS: A significant positive correlation was seen for ST1A1, FGF-19 and NT-3 whereas EN-RAGE, DNER, CX3CL1 and TWEAK associated inversely with BOP, PPD≥ 5mm and MBL but positively with number of teeth. Several CD markers (CD244, CD40, CDCP1, LIF-R, IL-10RA, CD5 and CD6) were found to be associated with BOP, shallow and deep pockets, MBL and number of teeth, either directly or inversely. Most chemokines (CCL8, CX3CL1, CXCL10, CXCL11, CCL11, CCL4, CCL20, CXCL5, CXCL6, and CCL23) were positively associated with number of teeth and some inversely related to MBL (CCL8, CXCL10). Proteins with enzymatic activity (ST1A1, HGF and CASP-8) were directly related to the severity of periodontal conditions and inversely related to number of teeth. Aside from FGF-19, other growth factors were also directly associated with MBL (HGF), number of teeth (VEGF-A, LAP TGF-beta-1) and, inversely to, shallow pockets (LAP TGF-beta-1, TGFA and Beta-NGF). Out of 33 cytokines, 32 associated inversely with shallow pockets, whereas only CD40 associated positively. Associations between cytokines and periodontal parameters in the RA group were comparatively less. Statistical analyses were adjusted for multivariate effects using the Benjamini-Hochberg false discovery rate method. CONCLUSION: Systemic inflammatory burden, via known and novel markers, is associated with periodontal conditions in PD and RA subjects. Shallow pockets are not associated with a higher inflammatory state.

Haematological toxicity in adult patients receiving craniospinal irradiation--indication of a dose-bath effect.

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the correlation between the haematological toxicity observed in patients treated with craniospinal irradiation, and the dose distribution in normal tissue, specifically the occurrence of large volumes exposed to low dose. MATERIALS AND METHODS: Twenty adult male patients were included in this study; eight treated with helical tomotherapy (HT), and twelve with three-dimensional conformal radiation therapy. The relative volume of red bone marrow and body that was exposed to low dose (i.e. the so-called dose bath) was evaluated and correlated with nadir blood values during treatment, i.e. the severity of anaemia, leukopaenia, and thrombocytopaenia. The correlation was tested for different dose levels representing the dose bath using the Pearson product-moment correlation method. RESULTS: We found a significant correlation between the volume of red bone marrow exposed to low dose and the severity of thrombocytopaenia during treatment. Furthermore, for the HT patients, a significant correlation was found between the relative volume of the body exposed to low dose and the severity of anaemia and leukopenia. CONCLUSIONS: The severity of haematological toxicity correlated with the fraction of red bone marrow or body that was exposed to low dose.

Pre-diabetes and diabetes: Medical risk factors and periodontal conditions.

OBJECTIVE: The aim of this study was to evaluate the difference between subjects with pre-diabetes, well or poorly controlled diabetes mellitus type 2 (T2D) and non-diabetes concerning such medical risk factors as hemoglobin A1c, body mass index (BMI) and waist circumference (WC) with periodontal conditions. MATERIALS AND METHODS: BMI, WC, PI, BOP, PD and marginal bone level (MBL) were recorded. Hemoglobin A1c (HbA1c) level and random blood glucose level (RBGL) were analyzed. RESULTS: Forty-five subjects were pre-diabetics, 64 subjects had poorly controlled T2D, 28 subjects had well controlled T2D and 76 subjects were non-diabetics. Non-diabetics, pre-diabetics as well as subjects with T2D were overweight. Females in all groups had increased mean levels of WC. Number of PD ≥ 6 mm were increased in subjects with poorly controlled T2D compared to non-diabetics and pre-diabetics (p < 0.05). CONCLUSIONS: Pre-diabetic subjects showed the same periodontal conditions as non-diabetic subjects. Forty-five of the subjects reporting to have no diabetes were pre-diabetics. Non-diabetic, pre-diabetic and diabetic subjects were overweight. Subjects with poorly controlled T2D had severe periodontal conditions.

Treatment plan comparison using grading analysis based on clinical judgment.

PURPOSE: In this work we explore a method named clinical grading analysis (CGA) which is based on clinical assessments performed by radiation oncologists (ROs). The purpose is to investigate how useful the method is for treatment plan comparisons, and how the CGA results correlate with dosimetric evaluation parameters, traditionally used for treatment plan comparisons. MATERIAL AND METHODS: Helical tomotherapy (HTT) and seven-beam step-and-shoot intensity modulated radiation therapy (SS-IMRT) plans were compared and assessed by 10 experienced ROs for 23 patient cases. A CGA was performed where the plans were graded based on how the ROs thought they compared to each other. The resulting grades from the CGA were analyzed and compared to dose-volume statistics and equivalent uniform dose (EUD) data. RESULTS: For eight of the 23 cases the CGA revealed a significant difference between the HTT and the SS-IMRT plans, five cases were in favor of HTT, and three in favor of SS-IMRT. Comparing the dose-volume statistics and EUD-data with the result from the CGA showed that CGA results correlated well with dose-volume statistics for cases regarding difference in target coverage or doses to organs at risk. The CGA results also correlated well with EUD-data for cases with difference in clinical target volume (CTV) coverage but the correlation for cases with difference in planning target volume (PTV) coverage was not as clear. CONCLUSIONS: This study presents CGA as a useful method of comparing radiotherapy treatment plans. The proposed method offers a formalized way of introducing and evaluating the implementation of new radiotherapy techniques in a clinical setting. The CGA identify patients that have a clinical benefit of one or the other of the advanced treatment techniques available to them, i.e. in this study HTT and SS-IMRT, which facilitates a more optimal use of a clinics' advanced treatment resources.

Introducing multiple treatment plan-based comparison to investigate the performance of gantry angle optimisation (GAO) in IMRT for head and neck cancer.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the performance of gantry angle optimisation (GAO) compared to equidistant beam geometry for two inverse treatment planning systems (TPSs) by utilising the information obtained from a range of treatment plans. MATERIAL AND METHODS: The comparison was based on treatment plans generated for four different head and neck (H&N) cancer cases using two inverse treatment planning systems (TPSs); Varian Eclipse™ representing dynamic MLC intensity modulated radiotherapy (IMRT) and Oncentra® Masterplan representing segmented MLC-based IMRT. The patient cases were selected on the criterion of representing different degrees of overlap between the planning target volume (PTV) and the investigated organ at risk, the ipsilateral parotid gland. For each case, a number of 'Pareto optimal' plans were generated in order to investigate the trade-off between the under-dosage to the PTV (V(PTV,D < 95%)) or the decrease in dose homogeneity (D(5)-D(95)) to the PTV as a function of the mean absorbed dose to the ipsilateral parotid gland ((parotid gland)). RESULTS: For the Eclipse system, GAO had a clear advantage for the cases with smallest overlap (Cases 1 and 2). The set of data points, representing the underlying trade-offs, generated with and without using GAO were, however, not as clearly separated for the cases with larger overlap (Cases 3 and 4). With the OMP system, the difference was less pronounced for all cases. The Eclipse GAO displays the most favourable trade-off for all H&N cases. CONCLUSIONS: We have found differences in the effectiveness of GAO as compared to equidistant beam geometry, in terms of handling conflicting trade-offs for two commercial inverse TPSs. A comparison, based on a range of treatment plans, as developed in this study, is likely to improve the understanding of conflicting trade-offs and might apply to other thorough comparison techniques.

Conversion of helical tomotherapy plans to step-and-shoot IMRT plans--Pareto front evaluation of plans from a new treatment planning system.

PURPOSE: The resulting plans from a new type of treatment planning system called SharePlan have been studied. This software allows for the conversion of treatment plans generated in a TomoTherapy system for helical delivery, into plans deliverable on C-arm linear accelerators (linacs), which is of particular interest for clinics with a single TomoTherapy unit. The purpose of this work was to evaluate and compare the plans generated in the SharePlan system with the original TomoTherapy plans and with plans produced in our clinical treatment planning system for intensity-modulated radiation therapy (IMRT) on C-arm linacs. In addition, we have analyzed how the agreement between SharePlan and TomoTherapy plans depends on the number of beams and the total number of segments used in the optimization. METHODS: Optimized plans were generated for three prostate and three head-and-neck (H&N) cases in the TomoTherapy system, and in our clinical treatment planning systems (TPS) used for IMRT planning with step-and-shoot delivery. The TomoTherapy plans were converted into step-and-shoot IMRT plans in SharePlan. For each case, a large number of Pareto optimal plans were created to compare plans generated in SharePlan with plans generated in the Tomotherapy system and in the clinical TPS. In addition, plans were generated in SharePlan for the three head-and-neck cases to evaluate how the plan quality varied with the number of beams used. Plans were also generated with different number of beams and segments for other patient cases. This allowed for an evaluation of how to minimize the number of required segments in the converted IMRT plans without compromising the agreement between them and the original TomoTherapy plans. RESULTS: The plans made in SharePlan were as good as or better than plans from our clinical system, but they were not as good as the original TomoTherapy plans. This was true for both the head-and-neck and the prostate cases, although the differences between the plans for the latter were small. The evaluation of the head-and-neck cases also showed that the plans generated in SharePlan were improved when more beams were used. The SharePlan Pareto front came close to the front for the TomoTherapy system when a sufficient number of beams were added. The results for plans generated with varied number of beams and segments demonstrated that the number of segments could be minimized with maintained agreement between SharePlan and TomoTherapy plans when 10-19 beams were used. CONCLUSIONS: This study showed (using Pareto front evaluation) that the plans generated in Share-Plan are comparable to plans generated in other TPSs. The evaluation also showed that the plans generated in SharePlan could be improved with the use of more beams. To minimize the number of segments needed in a plan with maintained agreement between the converted IMRT plans and the original TomoTherapy plans, 10-19 beams should be used, depending on target complexity. SharePlan has proved to be useful and should thereby be a time-saving complement as a backup system for clinics with a single TomoTherapy system installed alongside conventional C-arm linacs.

Beam commissioning and measurements validating the beam model in a new TPS that converts helical tomotherapy plans to step-and-shoot IMRT plans.

PURPOSE: A new type of treatment planning system called SHAREPLAN has been studied, which enables the transfer of treatment plans generated for helical tomotherapy delivery to plans that can be delivered on C-arm linacs. The purpose is to ensure continuous patient treatment during periods of unscheduled downtime for the TomoTherapy unit, particularly in clinics without a backup unit. The purpose of this work was to verify that the plans generated in this novel planning system are deliverable and accurate. The work consists primarily of beam commissioning, verification of the beam model, and measurements verifying that generated plans are deliverable with sufficient accuracy. METHODS: The beam commissioning process involves input of general geometric properties of the modeled linac, profiles and depth dose curves for a specific photon nominal energy (6 MV), and the automated modeling of other beam properties. Some manual tuning of the beam model is required. To evaluate its accuracy, the confidence limit concept [J. Venselaar et al., "Tolerances for the accuracy of photon beam dose calculations of treatment planning systems," Radiother. Oncol. 60, 191-201 (2001)] was used, which is a method supported by ESTRO. Measurements were conducted with a 2D diode array at the commissioned linac as a final check of the beam model and to evaluate whether the generated plans were deliverable and accurate. RESULTS: The comparison and evaluation of calculated data points and measured data according to the method applied confirmed the accuracy of the beam model. The profiles had a confidence limit of 1.1% and the depth dose curves had a confidence limit of 1.7%, both of which were well below the tolerance limit of 2%. Plan specific QC measurements and evaluation verified that different plans generated in the TPS were deliverable with sufficient accuracy at the commissioned linac, as none of the 160 beams for the 20 different plans evaluated had a fraction of approved data points below 90%, the local clinical approval criterion for delivery QA measurements. CONCLUSIONS: This study is a validation of the new TPS as it verifies that the generated plans are deliverable at a commissioned linac with adequate accuracy. A thorough investigation of the treatment plan quality will require a separate study. The TPS is proving to be a useful and time-saving complement, especially for clinics having a single unit for helical delivery among its conventional linacs.

Periodontal conditions, oral Candida albicans and salivary proteins in type 2 diabetic subjects with emphasis on gender.

BACKGROUND: The association between periodontal conditions, oral yeast colonisation and salivary proteins in subjects with type 2 diabetes (T2D) is not yet documented. The present study aimed to assess the relationship between these variables in type 2 diabetic subjects with reference to gender. METHODS: Fifty-eight type 2 diabetic subjects (23 males and 35 females) with random blood glucose level >or= 11.1 mmol/L were investigated. Periodontal conditions (plaque index [PI], bleeding on probing [BOP], probing pocket depth [PD] (4 to 6 mm and >or= 6 mm), oral yeasts, salivary immunoglobulin (Ig) A, IgG and total protein concentrations, and number of present teeth were determined. RESULTS: Periodontal conditions (PI [p < 0.00001], BOP [p < 0.01] and PD of 4 to 6 mm [p < 0.001], salivary IgG (microg)/mg protein (p < 0.001) and salivary total protein concentrations (p < 0.05) were higher in type 2 diabetic females with Candida albicans (C. albicans) colonisation compared to males in the same group. Type 2 diabetic females with C. albicans colonisation had more teeth compared to males in the same group (p < 0.0001). CONCLUSION: Clinical and salivary parameters of periodontal inflammation (BOP and IgG (mug)/mg protein) were higher in type 2 diabetic females with oral C. albicans colonisation compared to males in the same group. Further studies are warranted to evaluate the association of gender with these variables in subjects with T2D.