Treatment Planning Protocol Research Articles

A Cross-Sectional Survey of the Use of Clear Aligners by General Dentists in Australia.

The primary aim of the investigation was to survey clear aligner therapy (CAT) use among general dentists in Australia. A secondary aim was to evaluate the factors that influenced general dentists in Australia not to provide CAT. General dentists registered with the Australian Health Practitioner Regulation Agency were invited to participate in a structured cross-sectional electronic survey. The survey covered demographics, preferred CAT systems and practices, relevant treatment planning and retention protocols, patient-reported CAT issues, pertinent respondent opinions, and reasons for not providing CAT. Descriptive statistics were computed via GraphPad Prism v10 (GraphPad Software Inc., La Jolla, CA, USA). Most of the 264 (n = 172; 65.2%) respondents indicated that they provided CAT. The majority (n = 82; 58.6%) reported that they treated between 1 and 20 patients with CAT annually. Invisalign was the most used system (n = 83; 61.2%), with 55 (41.7%), indicating that they used more than one system. Most (n = 124; 98.4%) were comfortable using CAT for mild crowding, whereas 73.4% (n = 94) were not comfortable in treating severe crowding with CAT. The median (IQR) number of patients per respondent treated with extraction of a permanent incisor or premolar was 0 (0). Issues regarding tooth positions were reportedly always or mostly in need of change in the initial treatment plan by 68.7%. Problems regarding patient compliance with CAT wear protocols (n = 67; 45.6%) and the predictability of treatment outcomes (n = 31; 21.1%) were the most identified themes of the free-text comments. Over 80% of those who did not provide CAT indicated that they preferred to refer to an orthodontist for management. Almost two-thirds of the respondents provided CAT. Invisalign was the most used system. The majority use CAT combined with nonextraction treatment. Most of those who did not provide CAT preferred to refer to an orthodontist for patient management.

Interstitial and Intraluminal Photodynamic Therapy – The Munich Experiences

Different clinical aspects of photodynamic therapy (PDT), like treatment planning, treatment and dosimetry protocols, spectral on-line-monitoring (SOM) as well as follow-up evaluation of clinical outcome, are of interest regarding further iPDT developments. For three specific applications, interstitial PDT (iPDT) for prostate cancer in urology, intraluminal PDT for cholangiocarcinoma in gastroenterology and stereotactic iPDT for glioblastoma in neurosurgery, the clinical scenario is described. If all information arising around a PDT intervention is combined, as shown on the example iPDT for glioblastoma, further insight about the involved processes and mechanisms can be derived and utilized to develop the therapeutic approach further as a whole.

Adverse Events Related to Direct-To-Consumer Sequential Aligners-A Study of the MAUDE Database.

Background-Direct-to-consumer (DTC) sequential aligners promote "teeth straightening" at a low cost and with added patient convenience. DTC sequential aligners have risen in popularity among the general public and sparked debate among dental professionals. Dental professionals argue that using these aligners without an in-person diagnosis and treatment planning protocol set by a licensed dentist or orthodontist may lead to adverse effects on teeth and surrounding structures. The objective of this study is to describe adverse clinical events associated with the use of DTC sequential aligners as reported in the Food and Drug Administration's Manufacturer and User Facility Device Experience (FDA MAUDE) database. Methods-We searched the MAUDE database from 1 January 2010 to 31 December 2020 for the product code of 'NXC' (sequential aligners). The year, type of adverse event, reporter occupation, and event description were noted. Results-651 reports associated with sequential aligners were found, of which 104 were related to DTC sequential aligners. Fifty-four adverse events were reported in 2019. From the event description, 41.3% comprised bite problems, 29.8% comprised orofacial pain, and 26.6% of patients had some form of periodontal sequelae. Furthermore, 69.2% of the patients followed up after an adverse event with a dentist not associated with DTC aligners. Conclusions-The use of DTC sequential aligners without dental supervision has led to oral health problems, as documented in the MAUDE database. Commonly reported adverse events include bite problems, pain, sensitivity, and periodontal disease, and some adverse events are irreversible.

Treatment planning protocols with the Invisalign appliance: an exploratory survey.

To investigate the changes made by orthodontists to the initial digital treatment plan (DTP) regarding the Invisalign appliance provided by Align Technology until acceptance of the plan by the orthodontist. The DTPs of subjects who underwent treatment with the Invisalign appliance and satisfied inclusion criteria were assessed to determine the number of DTPs and changes regarding prescription of aligners, composite resin (CR) attachments, and interproximal reduction (IPR) between the initial DTP and the accepted plan. Statistical analyses were calculated via GraphPad Prism 9.0 (GraphPad Software Inc., La Jolla, Calif). Most of the 431 subjects who satisfied inclusion/exclusion criteria were female (72.85%). More DTPs were required for subjects who had orthodontic extractions (median [interquartile range; IQR]: 4 [3, 5]) compared with those who did not (median [IQR]: 3 [2, 4], P < .0001). The median (IQR) overall number of aligners prescribed in the accepted DTP (30 [20, 39]) was greater than the initial DTP (30 [22,41], P < .001). The number of teeth used for CR attachments increased from the initial to the accepted DTP (P < .001). More CR attachments were observed in extraction treatment DTPs with a prescribed 2-week aligner change protocol compared with nonextraction treatment (P < .0001). The number of contact points with prescribed IPR increased between initial and accepted DTPs (P < .0001). Significant changes regarding DTP protocols were observed between the initial and accepted DTPs and between nonextraction and extraction-based CAT.

Screw-Retained Implant Supported Protheses on a Coronally Positioned Free Fibula Flap after Ameloblastoma Resection: A Case Report

A detailed multidisciplinary approach for the management of a patient with a mandibular defect caused by an ameloblastoma through the use of three fibula flap blocks and a fixed screw-retained implant supported prosthesis will be discussed. Diagnosis, treatment planning, surgical and prosthetic protocols are described, as well as clinical and radiographic results after six years.

Dosimetric Impact of Inter-Fraction Anatomical Changes in Carbon Ion Boost Treatment for High-Risk Prostate Cancer (AIRC IG 14300).

Rectum and bladder volumes play an important role in the dose distribution reproducibility in prostate cancer adenocarcinoma (PCa) radiotherapy, especially for particle therapy, where density variation can strongly affect the dose distribution. We investigated the reliability and reproducibility of our image-guided radiotherapy (IGRT) and treatment planning protocol for carbon ion radiotherapy (CIRT) within the phase II mixed beam study (AIRC IG 14300) for the treatment of high-risk PCa. In order to calculate the daily dose distribution, a set of synthetic computed tomography (sCT) images was generated from the cone beam computed tomography (CBCT) images acquired in each treatment session. Planning target volume (PTV) together with rectum and bladder volume variation was evaluated with sCT dose-volume histogram (DVH) metric deviations from the planning values. The correlations between the bladder and rectum volumes, and the corresponding DVH metrics, were also assessed. No significant difference in the bladder, rectum, and PTV median volumes between the planning computed tomography (pCT) and the sCT was found. In addition, no significant difference was assessed when comparing the average DVHs and median DVH metrics between pCT and sCT. Dose deviations determined by bladder and rectum filling variations demonstrated that dose distributions were reproducible in terms of both target coverage and organs at risk (OARs) sparing.

A Multicentre Evaluation of Dosiomics Features Reproducibility, Stability and Sensitivity.

Simple SummaryDosiomics is born directly as an extension of radiomics: it entails extracting features from the patients’ three-dimensional (3D) radiotherapy dose distribution rather than from conventional medical images to obtain specific spatial and statistical information. Dosiomic studies, in a multicentre setting, require assessing the features’ stability to dose calculation settings and the features’ capability in distinguishing different dose distributions. This study provides the first multicentre evaluation of the dosiomic features in terms of reproducibility, stability and sensitivity across various dose distributions obtained from multiple technologies and techniques and considering different dose calculation algorithms of TPS and two different resolutions of the dose grid. Harmonisation strategies to account for a possible variation in the dose distribution due to these confounding factors should be adopted when investigating a correlation between dosiomic features and clinical outcomes in multicentre studies.Dosiomics is a texture analysis method to produce dose features that encode the spatial 3D distribution of radiotherapy dose. Dosiomic studies, in a multicentre setting, require assessing the features’ stability to dose calculation settings and the features’ capability in distinguishing different dose distributions. Dose distributions were generated by eight Italian centres on a shared image dataset acquired on a dedicated phantom. Treatment planning protocols, in terms of planning target volume coverage and dose–volume constraints to the organs at risk, were shared among the centres to produce comparable dose distributions for measuring reproducibility/stability and sensitivity of dosiomic features. In addition, coefficient of variation (CV) was employed to evaluate the dosiomic features’ variation. We extracted 38,160 features from 30 different dose distributions from six regions of interest, grouped by four features’ families. A selected group of features (CV < 3 for the reproducibility/stability studies, CV > 1 for the sensitivity studies) were identified to support future multicentre studies, assuring both stable features when dose distributions variation is minimal and sensitive features when dose distribution variations need to be clearly identified. Dosiomic is a promising tool that could support multicentre studies, especially for predictive models, and encode the spatial and statistical characteristics of the 3D dose distribution.

Early Detection of Radiation-Induced Injury and Prediction of Cognitive Deficit by MRS Metabolites in Radiotherapy of Low-Grade Glioma.

Purpose To compare the sensitivity of MRS metabolites and MoCA and ACE-R cognitive tests in the detection of radiation-induced injury in low grade glioma (LGG) patients in early and early delayed postradiation stages. Methods MRS metabolite ratios of NAA/Cr and Cho/Cr, ACE-R and MoCA cognitive tests, and dosimetric parameters in corpus callosum were analyzed during RT and up to 6-month post-RT for ten LGG patients. Results Compared to pre RT baseline, a significant decline in both NAA/Cr and Cho/Cr in the corpus callosum was seen at the 4th week of RT, 1, 3, and 6-month post-RT. These declines were detected at least 3 months before the detection of declines in cognitive functions by ACE-R and MoCA tools. Moreover, NAA/Cr alterations at 4th week of RT and 1-month post-RT were significantly negatively correlated with the mean dose received by the corpus callosum, as well as the corpus callosum 40 Gy dose volume, i.e., the volume of the corpus callosum receiving a dose greater than 40 Gy. Conclusion MRS-based biomarkers may be more sensitive than the state-of-the-art cognitive tests in the prediction of postradiation cognitive impairments. They would be utilized in treatment planning and dose sparing protocols, with a specific focus on the corpus callosum in the radiation therapy of LGG patients.

The Hypnotic Induction Profile (HIP) in Clinical Practice and Research

ABSTRACT The Hypnotic Induction Profile (HIP) was developed as a brief, yet thorough, assessment of a person’s level of trait hypnotizability and their potential to experience a hypnotic state. The HIP quantitatively and qualitatively measures hynotizability by evaluating biological and sensorimotor experiences designed to assess 3 fundamental observable and measurable components of hypnosis: absorption, dissociation, and suggestibility through a guided assessment that takes 5 to 10 minutes. From conception, the HIP has been utilized in clinical settings to assess appropriateness for the use of hypnosis in treatment planning and research protocols to stratify research participants. The brevity, accessibility, and reliability of the HIP have allowed it to adapt, not only across settings but through media platforms as technology and remote delivery become increasingly incorporated in the field of hypnosis.

Dosimetric Comparison of Superflab and Specially Prepared Bolus Materials Used in Radiotherapy Practice.

This study compares standard commercial bolus material (Superflab) to custom prepared silicone dental impression material (CDIM) and play dough material (PDM) with respect to dosimetric properties and applicability by using ion chamber measurement and calculated dose values. The CDIM bolus was prepared by mixing dental impression silicone material with enough water to maintain a density of about 1.0 g/cm3. The prepared bolus material is applied on an RW3 solid phantom by covering 10x10 cm2 area with 0.5-1 cm thickness. Ion chamber measurements were performed separately with and without bolus material application. The setup was scanned in CT and the same procedure was repeated in the TPS using the scan data, in which the Pencil Beam Convolution dose calculation algorithm was used. To compare the effect of bolus material on tissue, the Superflab bolus and CDIM bolus were applied with 1 cm of thickness on postmastectomy scar and dose calculations on TPS were performed. After comparison of the dosimetric values for Superflab, CDIM and PDM, we obtained statistically meaningful results between superflab and CDIM. For PDM, the results obtained with TPS and ion chamber measurements indicated that, it is not suitable to use in radiotherapy application due to its material properties. For the simulated skin dose values obtained at five random points on the scar tissue, the comparison of Superflab and CDIM TPS calculation results were not statistically significant. The CDIM is easy to prepare and apply on irregular mastectomy scar tissue and it prevents formation of air gaps in the application surface. Especially for curved anatomical regions such as scar tissue, inclusion of the bolus material in treatment planning protocol will reduce dose uncertainty in application. It is safe to use CDIM as an alternative to Superflab in radiotherapy application, whereas PDM is not useful in clinical practice due to its material properties.

Harmonization of proton treatment planning for head and neck cancer using pencil beam scanning: first report of the IPACS collaboration group

Background and purpose: A collaborative network between proton therapy (PT) centres in Trento in Italy, Poland, Austria, Czech Republic and Sweden (IPACS) was founded to implement trials and harmonize PT. This is the first report of IPACS with the aim to show the level of harmonization that can be achieved for proton therapy planning of head and neck (sino-nasal) cancer.Methods: CT-data sets of five patients were included. During several face-to-face and online meetings, a common treatment planning protocol was developed. Each centre used its own treatment planning system (TPS) and planning approach with some restrictions specified in the treatment planning protocol. In addition, volumetric modulated arc therapy (VMAT) photon plans were created.Results: For CTV1, the average Dmedian was 59.3 ± 2.4 Gy(RBE) for protons and 58.8 ± 2.0 Gy(RBE) for VMAT (aim was 56 Gy(RBE)). For CTV2, the average Dmedian was 71.2 ± 1.0 Gy(RBE) for protons and 70.6 ± 0.4 Gy(RBE) for VMAT (aim was 70 Gy(RBE)). The average D2% for the spinal cord was 25.1 ± 8.5 Gy(RBE) for protons and 47.6 ± 1.4 Gy(RBE) for VMAT. The average D2% for chiasm was 46.5 ± 4.4 Gy(RBE) for protons and 50.8 ± 1.4 Gy(RBE) for VMAT, respectively. Robust evaluation was performed and showed the least robust plans for plans with a low number of beams.Discussion: In conclusion, several influences on harmonization were identified: adherence/interpretation to/of the protocol, available technology, experience in treatment planning and use of different beam arrangements. In future, all OARs that should be included in the optimization need to be specified in order to further harmonize treatment planning.

Prolonged heating in nontargeted tissue during MR-guided focused ultrasound of bone tumors.

Thermal dosimetry during MR-guided focused ultrasound (MRgFUS) of bone tumors underpredicts ablation zone. Intraprocedural understanding of heat accumulation near bone is needed to prevent undesired treatment of nontargeted tissue. Temperature decay rates predict prolonged, spatially varying heating during MRgFUS bone treatments. Prospective case series. Nine patients with localized painful bone tumors (five bone metastasis, four osteoid osteomas), were compared with five patients with uterine fibroid tumors treated using MRgFUS. Proton resonance frequency shift thermometry using 2D-GRE with echo-planar imaging at 3 T. Tissue response was derived by fitting data from extended thermometry acquisitions to a decay model. Decay rates and time to peak temperature (TTP) were analyzed in segmented zones between the bone target and skin. Decay rates were used to calculate intersonication cooling times required to return to body temperature; these were compared against conventional system-mandated cooling times. Kolmogorov-Smirnov tests for normality, and Student's t-test was used to compare decay rates. Spatial TTP delay and predicted cooling times used Wilcoxon signed rank tests. P < 0.05 was significant. Tissue decay rates in bone tumor patients were 3.5 times slower than those in patients with fibroids (τbone = 0.037 ± 0.012 vs. τfibroid = 0.131 ± 0.010, P < 0.05). Spatial analysis showed slow decay rates effecting baseline temperature as far as 12 mm away from the bone surface, τ4 = 0.015 ± 0.026 (median ± interquartile range [IQR]). Tissue within 9 mm of bone experienced delayed TTP (P < 0.01). In the majority of bone tumor treatments, system-predicted intersonication cooling times were insufficient for nearby tissue to return to body temperature (P = 0.03 in zone 4). MRgFUS near bone is susceptible to long tissue decay rates, and unwanted cumulative heating up to 1.2 cm from the surface of the bone. Knowledge of decay rates may be used to alter treatment planning and intraprocedural thermal monitoring protocols to account for prolonged heating by bone. 4 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;50:1526-1533.

The impact of maintenance on peri-implant health.

Most of the literature evaluating dental implants focuses on implant survival, which is a limited proxy for the successful rehabilitation of patients with missing teeth. Success should include not only survival but also lack of mechanical, biological, and esthetics problems. A comprehensive review of local and systemic risk factors prior to implant placement will allow the tailoring of treatment planning and maintenance protocols to the patient's profile in order to achieve longitudinal success of the therapy. This review discusses the role of controlling different risk factors and prevention/treatment of peri-implant mucositis in order to avoid peri-implantitis. Although the literature addressing the topic is still scarce, the existing evidence shows that performing optimal plaque control and regular visits to the dentist seem to be adequate to prevent peri-implant lesions. Due to impossibility of defining a probing depth associate with peri-implant health, radiographic evaluations may be considered in the daily practice. So far, there is a strong evidence linking a past history of periodontal disease to peri-implant lesions, but this is not so evident for other factors including smoking and diabetes. The prevention of biological complications starts even before implant placement and include a broader analysis of the patient risk profile and tailoring the rehabilitation and maintenance protocols accordingly. It should be highlighted that the installation of implants does not modify the patient profile, since it does not modify genetics, microbiology or behavioral habits of any individual.

The influence of guided sleeve height, drilling distance, and drilling key length on the accuracy of static Computer-Assisted Implant Surgery.

The aim of this study was to evaluate the effect of guided sleeve height, drilling distance, and guided key height on accuracy of static Computer-Assisted Implant Surgery (sCAIS). Pre and post-operative positions of implants placed in duplicate dental models were compared and recorded after placement of implants according to a standardized treatment planning and execution sCAIS protocol. Guided sleeve heights: 2 mm, 4 mm, 6 mm and guided key heights: 1 mm and 3 mm were equally randomized in six test groups with varying implant lengths (10-16 mm) and surgical drilling protocols. The mean crestal and apical three-dimensional (3D) deviation, as well as the angular deviation were calculated for each group. Data was analyzed using multivariate analysis anova. P values less than .05 were considered statistically significant. All P values of post-hoc tests were corrected for multiple testing using Bonferroni-Holm's adjustment method. 3D implant positioning accuracy was not significantly affected by the difference in sleeve height alone or by the implant length alone (P > .05). However, 3D and angular deviation values became significantly higher as the total drilling distance below the guided sleeve increased and significantly became lower as the guided key height above the sleeve increased. 18 mm drilling distance resulted in a significantly higher deviation, when compared to 14 mm or 16 mm drilling distances, irrespective of sleeve height or implant length (P < .01). 3 mm key height resulted in significantly less 3D deviation than 1 mm key height (P < .01). Decreasing the drilling distance below the guided sleeve, by using shorter sleeve heights or shorter implants can significantly increase the accuracy of sCAIS.

26. Implementation of a new optimization algorithm in VMAT for the treatment of prostate cancer

Introduction The aim of the current study is to evaluate a new optimization algorithm available since the Eclipse’s version 13.6 (Varian): Photon Optimizer version 13 (PO13). The purpose is to obtain a treatment planning protocol for prostate cancer treatments, reproducible which can be delivered by the treatment machine (patient’s quality assurance QA) and evaluate the dosimetric gain for patients (better organ at risk protection). Methods In our department, the medical prescription for the patients treated for a prostate cancer is a 75 Gy dose (2.5 Gy per fraction) on the prostate (PTVPRO) and a 46 Gy dose (2 Gy per fraction) on the right and left iliac lymph nodes. Treatments planning are made of 2 treatment plans: a first treatment plan in integrated boost, delivering a dose of 57.5 Gy on the PTVPRO and of 46 Gy on the PTVGGs in 23 fractions, and the 2nd treatment plan with a dose of 17.5 Gy on the PTVPRO in 7 fractions. Plans are optimized with PO13 and are calculated in the Eclipse’s Treatment Planning System (AAA algorithm, Varian) version 13.5 in order to be delivered on a Truebeam (Varian) version 2.5 MR2 in VMAT (arcs of 6 MV, dose rate: 600 UM/min). Several adjustable parameters with PO13 are tested on one patient: Normal Tissue Optimization NTO’s influence, calculation resolution during the optimization (1.25 mm, 2.5 mm and 5 mm), one or more arcs, optimization volumes, PTV’s priority compared to OAR priority, PTV’s priority compared to NTO priority, use of the intermediate dose calculation. The methodology used is to obtain the best PTV’s cover, changing a single parameter at each optimization without optimising relatively to the OAR at first. Parameters chosen and fixed, the constraints on the OAR are introduced. These parameters will be tested with several patients (reproducibility). The plan’s dosimetric evaluation is realised with the following Dose Volume Histogram (DVH): - For PTV: D95%, D98%, D2%, Dmin and Confomation Number (CN)1. - For OAR: bladder and rectum (Dmax, V35Gy, V50Gy), femoral heads (Dmax and Dmean). The monitor units number (MU) per arc is also noted. The dosimetric benefit for the patient will be evaluated in comparison with the real treatment plan calculated with the PRO13 algorithm (Progressive Resolution Optimizer algorithm version 13). The validation of the patient QA of these plans will be realised with the portal imager (Gamma index, PDIP Varian). Results The protocol will be based on the plan presenting a sufficient coverage for the PTV with the best CN taking into account the DVH values on the OAR. The 57.5 Gy plan chosen is Plan_1 (Table 1) with 2 arcs, a priority of 200 on the PTV for a priority of 500 on the NTO (automatic), a calculation resolution of 2.5 mm, an intermediate dose calculation. Plan_2 with a single arc has D98% and D95% reduced by 1 Gy compared to the other plans and Plan_4 has a CN too weak on the two PTV. Plan_3 with a calculation resolution of 1.25 mm seems the same as Plan_1 but the optimization time is multiplied by 2, a resolution of 2.5 mm is therefore preferred. The first results including the OAR’s constraints (priority of 100) shows that there is a significant reduction of DVH values V35Gy and V50Gy between the PRO13 and the new protocol in PO13 (Table 1). Download : Download high-res image (261KB) Download : Download full-size image Conclusions This study allowed us to simplify our practices with the use of the NTO as a replacement for optimization volumes (rings). It appears that the treatment plans obtained with PO13 allow a better saving of OAR with an equivalent coverage of PTV.

Comparison of the accuracy of maxillary position between conventional model surgery and virtual surgical planning

The aim of this study was to determine whether virtual surgical planning (VSP) is an accurate method for positioning the maxilla when compared to conventional articulator model surgery (CMS), through the superimposition of computed tomography (CT) images. This retrospective study included the records of 30 adult patients submitted to bimaxillary orthognathic surgery. Two groups were created according to the treatment planning performed: CMS and VSP. The treatment planning protocol was the same for all patients. Pre- and postoperative CT images were superimposed and the linear distances between upper jaw reference points were measured. Measurements were then compared to the treatment planning, and the difference in accuracy between CMS and VSP was determined using the t-test for independent samples. The success criterion adopted was a mean linear difference of <2mm. The mean linear difference between planned and obtained movements for CMS was 1.27±1.05mm, and for VSP was 1.20±1.08mm. With CMS, 80% of overlapping reference points had a difference of <2mm, while for VSP this value was 83.6%. There was no statistically significant difference between the two techniques regarding accuracy (P>0.05).

A split-parotid delineation approach for dose optimization in volumetric modulated arc therapy for nasopharyngeal carcinoma patients with parapharyngeal space invasion and level IIa cervical lymph node involvements.

This study evaluated the potential benefit of a split-parotid delineation approach on the parotid gland in the treatment planning of patients with nasopharyngeal carcinoma (NPC). 50 patients with NPC with parapharyngeal space (PPS) and/or level IIa cervical node involvements were divided into three groups: PPS only, level IIa cervical node only and both. Two volumetric-modulated arc therapy plans were computed. The first plan (control) was generated based on the routine treatment-planning protocol, while the second plan (test) was computed with the split-parotid delineation approach, in which a line through the anterolateral margin of the retromandibular vein was created that divided the parotid gland into anterolateral and posteromedial subsegments. For the test plan, the anterolateral subsegment was prescribed, with a dose constraint of 25 Gy in the plan optimization. Dosimetric data of the parotid gland, target volumes and selected organs at risk (OARs) were compared between the control and test plans. The mean dose to the anterolateral subsegment of the parotid gland in all three groups was kept below 25 Gy. The test plan demonstrated significantly lower mean parotid dose than the control plan in the entire gland and the anterolateral subsegment in all three groups. The difference was the greatest in Group 3. The split-parotid delineation approach significantly lowered the mean dose to the anterolateral subsegment and overall gland without greatly compromising the doses to target volumes and other OARs. The effect was more obvious for both PPS and level IIa cervical node involvements than for either of them alone. It is the first article based on the assumption that parotid gland stem cells are situated at the anterolateral segment of the gland, and applied the split-parotid delineation approach to the parotid gland in the treatment planning of patients with NPC with PPS and level IIa cervical node involvements, so that the function of the post-radiotherapy parotid gland might be better preserved.

Jaw position uncertainty and adjacent fields in breast cancer radiotherapy.

Locoregional treatment of breast cancer involves adjacent, half blocked fields matched at isocenter. The objective of this work is to study the dosimetric effects of the uncertainties in jaw positioning for such a case, and how a treatment planning protocol including adjacent field overlap of 1 mm affects the dose distribution. A representative treatment plan, involving 6 and 15 photon beams, for a patient treated at our hospital is chosen. Monte Carlo method (EGSnrc/BEAMnrc) is used to simulate the treatment. Uncertainties in jaw positioning of ±1 mm are addressed, which implies extremes in reality of 2 mm field gap/overlap when planning adjacent fields without overlap and 1 mm gap or 3 mm overlap for a planning protocol with 1 mm overlap. Dosimetric parameters for PTV, lung and body are analyzed. Treatment planning protocol with 1 mm overlap of the adjacent fields does not considerably counteract possible underdosage of the target in the case studied. PTV‐V95% is for example reduced from 95% for perfectly aligned fields to 90% and 91% for 2 mm and 1 mm gap, respectively. However, the risk of overdosage in PTV and in healthy soft tissue is increased when following the protocol with 1 mm overlap. A 3 mm overlap compared to 2 mm overlap results in an increase in maximum dose to PTV, PTV‐D2%, from 113% to 121%. V120% for ‘Body‐PTV’ is also increased from 5 cm3 to 14 cm3. A treatment planning protocol with 1 mm overlap does not considerably improve the coverage of PTV in the case of erroneous jaw positions causing gap between fields, but increases the overdosage in PTV and doses to healthy tissue, in the case of overlapping fields, for the case investigated.PACS numbers: 87.55.D‐, 87.55.dk, 87.55.Gh, 87.55.K‐, 87.56.J‐

Quantitative Assessment of MRI Features in Patients with Relapsing-Remitting Multiple Sclerosis

Relapsing-remitting multiple sclerosis (RRMS) is a chronic inflammatory demyelinating disease of the central nervous system. Magnetic Resonance Imaging (MRI) has a remarkable role in the assessment of the disease. The aim of the study is to evaluate MRI features and also to determine linear correlation between them. Nineteen RRMS patients (5 males, 14 females) have been included in this study. Neurological examination using EDSS scores was performed for all patients. Each patient underwent T1, T2, Flair and DWI imaging. Twenty different features were evaluated in the research. Four features obtained directly from images, contain: DWI lesion size, number of DWI lesion, T2 lesion size and number of T2 lesion. In addition, EDSS is considered as one of the features. The volume of the lesion is presented as feature of lesion volume which is obtained by suitable software. In this paper we proposed a new method to calculate the rest of MRI features. The method uses histogram analysis of mean parenchymal diffusivity (MPD) map to calculate some features. The obtained features from the method contain: moment 2 to moment 6 (m2-m6), kurtosis, skewness, peak position (PP), peak height (PH), entropy (ENT), MPD-value, white matter fraction (WMF), gray matter fraction (GMF) and brain parenchymal fraction (BPF). Statistical results show EDSS has significant linear correlation with DWI lesion size, number of DWI lesion size, T2 lesion size and PP (P<0.05, R=[0.5-0.6]). All moments, m2m6, kurtosis, skewness and PH have significant linear correlation together (P<0.05, R=[0.81]). According to the results, ENT has negative significant correlation with m2-m6, kurtosis, skewness, PH (P<0.05, R=[-0.8-(-0.6)]) but has positive significant correlation with MPD-value and BPF (P<0.05, R=0.5). MPD-value has negative linear correlation with m2-m6, lesion volume and PH (P<0.05, R=[-0.8-(-0.5)]). The proposed method and features could be helpful in the analysis of treatment planning protocol and will be beneficial in the study of treatment effects.

An Inpatient Treatment and Discharge Planning Protocol for Alcohol Dependence: Efficacy in Reducing 30-Day Readmissions and Emergency Department Visits

Alcohol dependence results in multiple hospital readmissions, but no discharge planning protocol has been studied to improve outcomes. The inpatient setting is a frequently missed opportunity to discuss treatment of alcohol dependence and initiate medication-assisted treatment, which is effective yet rarely utilized. Our aim was to implement and evaluate a discharge planning protocol for patients admitted with alcohol dependence. The study took place at the San Francisco General Hospital (SFGH), a university-affiliated, large urban county hospital. Learner participants included Internal Medicine residents at the University of California, San Francisco (UCSF) who staff the teaching service at SFGH. Patient participants included inpatients with alcohol dependence admitted to the Internal Medicine teaching service. We developed and implemented a discharge planning protocol for patients admitted with alcohol dependence that included eligibility assessment and initiation of medication-assisted treatment. Rates of medication-assisted treatment increased from 0% to 64% (p value < 0.001). All-cause 30-day readmission rates to SFGH decreased from 23.4% to 8.2% (p value = 0.042). All-cause emergency department visits to SFGH within 30 days of discharge decreased from 18.8% to 6.1% (p value = 0.056). Through implementation of a discharge planning protocol by Internal Medicine residents for patients admitted with alcohol dependence, there was a statistically significant increase in medication-assisted treatment and a statistically significant decrease in both 30-day readmission rates and emergency department visits.