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Objective To compare the dosimetric differences of four fluence smoothing (FS) levels of the Monaco system in intensity-modulated radiation therapy (IMRT) after rectal cancer surgery, and to provide a reference for FS selection in clinical practice. Methods A total of 15 postoperative patients with rectal cancer admitted in 2020 were selected. Under the same optimal conditions, FS was set to Off, Low, Medium, and High for IMRT planning. The data were analyzed by SPSS 20.0 software. The dosimetric parameters of planning target volume and organs at risk (OARs), the number of Segments, the number of monitor units (MUs), the estimated total delivery time (ETDT), and the gamma pass rate were compared between the four FS levels. Results The four FS levels resulted in clinically acceptable dosimetric parameters of the planning target volume and OARs, and there was no significant difference in dose distribution between FS levels. From FS-Off to FS-High, number of Segments, number of Mus, and ETDT decreased by 15.2%, 11.8%, and 6.7%, respectively, whereas gamma pass rate increased by 1.6%. Conclusion The IMRT plans at four FS levels can meet the clinical requirements. Considering the planning quality and execution efficiency, FS-High is recommended for postoperative IMRT of patients with rectal cancer.
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Objective To explore the dosimetric differences of radiotherapy plan for cervical cancer with 4 different fluence smoothing (FS) parameters using Monaco treatment planning system (Monaco TPS). Methods Fifteen patients with ⅠB2 stage cervical cancer in our hospital were enrolled in this study. And a 2 Volumetric Modulated Arc Therapy (VMAT) plan for each patient were completed by Monaco 5.11 TPS according to the X-Ray Voxel Monte Carlo (XVMC) method. For each plan was optimized by FS function, with the level of Off, Low, Medium and High. To compare the difference of plan optimization time, conformity index (CI), Homogeneity index (HI), Dmean, Dmin, D2% of PTV，dose to the organ at risk (OAR)，the number of Segments# and MU#，estimated total delivery time (ETDT), quantum Efficiency (QE) of the plans, the formation of Segments# with the same angle and verification of inserting 729 two-dimensional matrix into PTW octavius 4D module of different FS function levels, with the precondition of the Prescription isodose curve covering 95% of the target area. The data was analysed by multivariate factor analysis with the application of SPSS, and P < 0.05 was considered as statistically significant. And the Planned revenue score of different FS levels was also calculated. Results Except for the Dmin of PTV (the lowest value is (32.09 ± 0.26) Gy for the Off group, and the highest value is (35.98 ± 0.42) Gy for the High group), V40 of the rectum (the lowest value in the Medium group is 55.88% ± 2.02%, and the highest value in the High group was 61.90% ± 2.98%) and bladder (the lowest value was 45.01% ± 2.08% in the Medium group, and the highest value is 50.45% ± 1.98% in the High group), the V20 (the lowest value High group was 49.05% ± 1.98%, the highest value Off group was 56.52% ± 1.75%) of femoral head (P < 0.05), there was no significant difference of the dose assessment results for PTV and OARs in 4 different FS function levels. In the High level, the ETDT, QE and MU# were showed better than other groups evidently, however, the number of Segments# showed no significant difference. The plan validation results was increased with the improvement of FS function level, and the level of High was considered to be the optimal. To compare the score of overall benefits of the plan, the level of Medium (−17.18 ± 0.05) got the highest score, and the Low group (−17.58 ± 0.05) and the High group (−17.42 ± 0.06) have similar scores, and Off group (−18.81 ± 0.08) has the lowest score. Conclusion Different FS levels of the Monaco 5.11 TPS can optimize the radiotherapy plan for cervical cancer, but the level of Medium is considered to be the most applicable.
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Resumo Este artigo, de natureza teórico-metodológica, discute a relação entre prosódia e compreensão leitora a partir de dois enfoques. O primeiro trata dos diferentes recursos metodológicos adotados na investigação dessa complexa relação, e o segundo versa sobre a controvérsia existente quanto à maneira como se configura essa relação. Reflexões como essas permitem aprofundar o conhecimento acerca das características dos diferentes recursos metodológicos adotados na investigação de dado fenômeno, assim como contribuem para esclarecer controvérsias em determinado campo do conhecimento, como é o caso da relação entre prosódia e compreensão leitora, tema ainda aberto a muitas interpretações. As discussões tomam por base pesquisas realizadas com crianças matriculadas no ensino fundamental.
Abstract This theoretical and methodological study discusses the relationship between prosody and reading comprehension from two different approaches: 1) the different methodological resources adopted to investigate this complex relationship; 2) the existing controversy on how this relationship is configured. Reflections such as these allow for an in-depth knowledge on the characteristics of the different methodological resources used to study a given phenomenon and to clarify controversies in certain fields of knowledge, such as the prosody-reading comprehension relationship, a topic still open to different interpretations. The discussions presented here are based on research carried out with elementary school children.
Resumen Este artículo, de carácter teórico-metodológico, analiza la relación entre la prosodia y la comprensión lectora desde dos enfoques. El primer enfoque aborda los diferentes recursos metodológicos adoptados en la investigación de esta compleja relación, mientras que el segundo plantea la controversia existente sobre cómo se configura esta relación. Estas reflexiones nos permiten profundizar nuestro conocimiento acerca de las características de diferentes recursos metodológicos adoptados en la investigación de un fenómeno dado; también contribuye a esclarecer controversias en determinados campos del conocimiento, como la relación entre prosodia y comprensión lectora, tema que aún permanece abierto a diversas interpretaciones. Las discusiones que aquí se presentan están basadas en investigaciones realizadas con niños de escuela primaria.
Résumé Cet étude théorico-méthodologique traite de la relation entre la prosodie et la compréhension en lecture à partir de deux approches différentes: 1) les différentes ressources méthodologiques adoptées pour étudier cette relation complexe; 2) la controverse existante sur la façon dont cette relation est configurée. De telles réflexions permettent d'approfondir la connaissance des caractéristiques des différentes ressources méthodologiques adoptées pour étudier un phénomène donné et de clarifier les controverses dans certains domaines de savoir, comme la relation prosodie-compréhension en lecture, un sujet encore ouvert à différentes interprétations. Les discussions présentées ici sont basées sur des recherches menées auprès d'enfants de l'école primaire.
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Education, Primary and Secondary , Comprehension , Reading , LearningABSTRACT
Objective To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) plans optimized with 3 different fluence smoothing parameters using Monaco treatment planning system.Methods A total of 15 patients with middle and upper esophageal carcinoma were planned with Low fluence smoothing (Low),Medium fluence smoothing (Medium) and High fluence smoothing (High) during VMAT optimization.The dosimetric differences in D95,D conformity index (CI),homogeneity index (HI) of targets,dose volume histogram (DVH) of organs at risk (OARs),and monitor unit (MU) were compared.Results There were no significant differences in D95,D CI and HI of targets,as well as in V40 and D of the heart,V10,V20 and D of the lung,and segment number among plans optimized with different fluence smoothing techniques (P＞0.05).Plans with high fluence smoothing achieved less V30 of heart,Dmax of cord PRV (t=-2.167,-0.999,P＜0.05),lower MU (t=-3.148,-6.692,P＜O.05),but increased V5 of both lungs (t=1.306,-2.027,P＜O.05)compared with plans with Medium and Low fluence smoothing.Plans with low fluence smoothing irradiated higher dose to the V30 and D to heart (t=O.411,0.589,0.013,P＜0.05),but less V5 of the lungs (t=O.423,P＜0.05) compared with plans with medium fluence smoothing.Conclusions All VMAT plans with 3 different fluence smoothing can meet the clinical requirements.VMAT plans optimized with high fluence smoothing are recommended in the treatment of patients middle and upper thoracic esophageal carcinoma.
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Objective@#To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) plans optimized with 3 different fluence smoothing parameters using Monaco treatment planning system.@*Methods@#A total of 15 patients with middle and upper esophageal carcinoma were planned with Low fluence smoothing (Low), Medium fluence smoothing (Medium) and High fluence smoothing(High) during VMAT optimization. The dosimetric differences in D95, Dmean, conformity index (CI), homogeneity index (HI) of targets, dose volume histogram (DVH) of organs at risk (OARs), and monitor unit (MU) were compared.@*Results@#There were no significant differences in D95, Dmean, CI and HI of targets, as well as in V40 and Dmean of the heart, V10, V20 and Dmean of the lung , and segment number among plans optimized with different fluence smoothing techniques (P>0.05). Plans with high fluence smoothing achieved less V30 of heart, Dmax of cord PRV(t=-2.167, -0.999, P<0.05), lower MU (t=-3.148, -6.692, P<0.05), but increased V5 of both lungs (t=1.306, -2.027, P<0.05) compared with plans with Medium and Low fluence smoothing. Plans with low fluence smoothing irradiated higher dose to the V30 and Dmean to heart (t=0.411, 0.589, 0.013, P<0.05), but less V5 of the lungs (t=0.423, P<0.05) compared with plans with medium fluence smoothing.@*Conclusions@#All VMAT plans with 3 different fluence smoothing can meet the clinical requirements. VMAT plans optimized with high fluence smoothing are recommended in the treatment of patients middle and upper thoracic esophageal carcinoma.
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Objective To explore the feasibility of using the optimization parameters modification and optimization processes modification to reduce the total monitor units ( MUs ) in the Eclipse radiotherapy treatment planning system (TPS). Methods Based on the radiotherapy plan of 10 patients with nasopharyngeal carcinoma, a total of 90 plans were designed for 9 groups using different optimization parameters and processes. The total MUs and the exposure dose of the organs among the different plans were compared. Results There was no significant difference in the doses of the organs at risk (class I) under the premise of target dose requirements (all P>0.05). The increase of the weight of the target area and the organs at risk will increase the total MUs. The increase of the preset limit value of the minimum MUs in the subfield will reduce the total MUs. The increase of the fluence smoothness in the X and Y directions will increase the total MUs. An unreasonable minimum MU value will increase the total MUs. Under the condition that the organ exposure is not changed significantly, the influencing factors of MU are ranked as weight>fluence smoothness>minimum MUs. Conclusions Parameter setting and process planning can reduce the total MUs to a certain extent. However, due to the complexity of the influence of optimization parameters on the plan, the optimization process should be preferred. Especially in the Eclipse TPS, the method of gradual optimization to achieve the final dose distribution requirement and then remove the fluence re-optimization is more convenient and effective for reducing the total MUs.
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Background and Objective Various irradiances have been reported to be beneficial for the treatment of neuropathic pain with near infrared light. However, the mechanistic basis for the beneficial outcomes may vary based on the level of irradiance or fluence rate used. Using in vivo and in vitro experimentalmodels, this study determined the mechanistic basis of photobiomodulation therapy (PBMT) for the treatment of neuropathic pain using a high irradiance. Study Design/Materials and Methods ln vitro experiments: Cultured, rat DRG were randomly assigned to control or laser treatment (L T) groups with different irradiation times (2, 5, 30, 60 or 120s). The laser parameters were: output power » 960 mW, irradiance » 300mW/cm2, 808 nm wavelength and spot size » 3cm diameter/ area » 7.07cm2, with different fluences according to irradiation times. Mitochondrial metabolic activity was measured with the MTS assay. The DRG neurons were immunostained using a primary antibody to ß-Tubulin III. ln vivo experiments: spared nerve injury surgery (SNI), an animal model of persistent peripheral neuropathic pain, was used. The injured rats were randomly divided into three groups (n » 5). 1) Control: SNI without LT, 2) Short term: SNI with LT on day 7 and euthanized on day 7, 3) Long term: SNI with LT on day 7 and euthanized on day 22. An 808 nm wavelength laser was used for all treatment groups. Treatment was performed once on Day 7 post-surgery. The transcutaneous treatment parameters were: output power: 10 W, fluence rate: 270 mW/cm2, treatment time: 120s. The laser probe was moved along the course of the sciatic/sural nerve during the treatment. Within 1 hour of irradiation, behavior tests were performed to assess its immediate effect on sensory allodynia and hyperalgesia caused by SNI. Results ln vitro experiments: Mitochondrial metabolism was significantly lower compared with controls for all LT groups. Varicosities and undulations formed in neurites of DRG neurons with a cell body diameter 30µm or less. ln neurites of DRG neurons with a cell body diameter of greater than 30µm, varicosities formed only in the 120s group. ln vivo experiments: For heat hyperalgesia, there was a statistically significant reduction in sensitivity to the heat stimulus compared with the measurements done on day 7 prior to LT. A decrease in the sensitivity to the heat stimulus was found in the LT groups compared with the control group on day 15 and 21. For cold allodynia and mechanical hyperalgesia, a significant decrease in sensitivity to cold and pin prick was found within 1 hour after L T. Sensitivity to these stimuli returned to the control levels after 5 days post-L T. No significant difference was found in mechanical allodynia between control and L T groups for all time points examined. Conclusion These in vitro and in vivo studies indicate that treatment with an irradiance/fluence rate at 270 m W/cm2 or higher at the level of the nerve can rapidly block pain transmission. A combination therapy is proposed to treat neuropathic pain with initial high irradiance/fluence rates for fast pain relief, followed by low irradiance/ fluence rates for prolonged pain relief by altering chronic inflammation.
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Animals , Rats , Sensory Receptor Cells/metabolism , Low-Level Light Therapy/statistics & numerical data , Ganglia, Spinal , Hyperalgesia/therapy , Neuralgia/therapy , In Vitro Techniques/methods , Immunohistochemistry/methods , Analysis of Variance , Nerve RegenerationABSTRACT
BACKGROUND: Postinflammatory hyperpigmentation (PIH) is one of the most common adverse effects associated with dermatologic procedures, especially those for cosmetic purposes. Low fluence Q-Switched Nd:YAG laser (LFQS) has been widely used for this condition in the field, but reports in the literature are scarce. OBJECTIVE: We aimed to evaluate the clinical benefit and limitation of LFQS in the treatment of PIH after cosmetic procedures. METHODS: Patients with PIH after laser treatment were enrolled in the study. Patients were treated with LFQS at an interval of 2 to 3 weeks. Photographs were taken. Objective measurement included erythema and melanin indices at the same site. Two blinded assessors graded the degree of improvement using a photograph based on a quartile scale (0~3). Patient satisfaction after treatment was also reported. RESULTS: A total of 45 patients were included in the analysis. Patients received 10 treatment sessions. Patients who started LFQS treatment within 3 months after the causal event showed a better treatment outcome. Those who had a higher erythema index before treatment tended to respond less to the treatment. CONCLUSION: LFQS may be a good treatment modality for patients with PIH. Earlier treatment can provide rapid resolution and better clinical results. However, for patients with PIH combined with intense erythema, LFQS may not be the first choice to consider in the clinical field.
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Humans , Erythema , Hyperpigmentation , Melanins , Patient Satisfaction , Treatment OutcomeABSTRACT
PURPOSE: To evaluate the long-term effects of reduced-fluence photodynamic therapy (RF-PDT) combined with intravitreal anti-vascular endothelial growth factor (anti-VEGF) for polypoidal choroidal vasculopathy (PCV). METHODS: Twenty-two eyes of 21 patients with PCV that were followed up for more than 24 months after RF-PDT and anti-VEGF combination therapy were retrospectively reviewed. The patients received intravitreal anti-VEGF (bevacizumab 1.25 mg, ranibizumab 0.5 mg, or aflibercept 2.0 mg) within 7 days of PDT. Patients were retreated with either RF-PDT and anti-VEGF injection, or with only anti-VEGF injection, as indicated. The main outcome measures were best-corrected visual acuity (BCVA) and central foveal thickness (CFT), which were measured before and after combination therapy. RESULTS: During follow-up, the mean logMAR BCVA significantly improved from 0.75 at baseline to 0.54 at 12 months and 0.52 at 24 months (p=0.009 and p=0.032, respectively). The mean CFT significantly decreased from 409.8 µm at baseline to 234.1 µm at 12 months and 245.9 µm at 24 months (p<0.001 and p=0.001, respectively). In 20 eyes (90.9%), the BCVA remained stable or improved. CONCLUSIONS: The efficacy of this combination therapy for 24 months resulted in stabilized vision and anatomical improvement. RF-PDT combined with intravitreal anti-VEGF injection could be an effective treatment modality for patients with PCV.
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Humans , Choroid , Endothelial Growth Factors , Follow-Up Studies , Outcome Assessment, Health Care , Photochemotherapy , Ranibizumab , Retrospective Studies , Vascular Endothelial Growth Factor A , Visual AcuityABSTRACT
INTRODUCTION: The study aimed to investigate the interplay between Monte Carlo Variance (MCV) and fluence smoothing factor (FSF) in volumetric modulated arc therapy treatment planning by using a sample set of complex treatment planning cases and a X‑ray Voxel Monte Carlo–based treatment planning system equipped with tools to tune fluence smoothness as well as MCV. MATERIALS AND METHODS: The dosimetric (dose to tumor volume, and organ at risk) and physical characteristic (treatment time, number of segments, and so on) of a set 45 treatment plans for all combinations of 1%, 3%, 5% MCV and 1, 3, 5 FSF were evaluated for five carcinoma esophagus cases under the study. RESULT: Increase in FSF reduce the treatment time. Variation of MCV and FSF gives a highest planning target volume (PTV), heart and lung dose variation of 3.6%, 12.8% and 4.3%, respectively. The heart dose variation was highest among all organs at risk. Highest variation of spinal cord dose was 0.6 Gy. CONCLUSION: Variation of MCV and FSF influences the organ at risk (OAR) doses significantly but not PTV coverage and dose homogeneity. Variation in FSF causes difference in dosimetric and physical parameters for the treatment plans but variation of MCV does not. MCV 3% or less do not improve the plan quality significantly (physical and clinical) compared with MCV greater than 3%. The use of MCV between 3% and 5% gives similar results as 1% with lesser calculation time. Minimally detected differences in plan quality suggest that the optimum FSF can be set between 3 and 5.
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In this brief review we will discuss the reasoning and evolution of our current use of combined very high-fluence collagen crosslinking and laser in situ keratomileusis. Several presentations and pertinent publications are reviewed, along with the key steps of the enhanced LASIK procedure. Long term outcome data support the safety and efficacy of LASIK Xtra in stabilizing myopic but also hyperopic LASIK results. In conclusion, we have compelling evidence that LASIK Xtra is a safe and effective adjunct.
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PURPOSE: To investigate the safe, effective light dose for photodynamic therapy (PDT) in the treatment of chronic central serous chorioretinopathy (CSC). METHODS: Thirty-eight eyes of 37 patients with chronic CSC were recruited for this study. From November 2009 to July 2010 and from April 2011 to February 2012, PDT was performed using 50% and 25% of the full light dose in 27 eyes of 27 patients (group I) and 11 eyes of 10 patients (group II), respectively. The minimum follow-up period was 6 months. Mean change in best corrected visual acuity (BCVA) and central retinal thickness, hyperpermeability change from abnormal choriocapillaris, success rate, recurrence rate, and complications were analyzed. RESULTS: Group I showed that BCVA (log MAR) improved significantly from 0.33 +/- 0.17 to 0.14 +/- 0.15 at 6 months (p < 0.001). However, there was no significant improvement of BCVA (p = 0.050) in group II. One eye out of 27 eyes (3.7%) in group I and 5 eyes out of 11 eyes (45.5%) in group II showed recurrence at the 6-month follow-up (p = 0.016). After initial PDT, hyperpermeability from abnormal choriocapillaris reduced or disappeared at 95.5% in group I and 54.5% in group II at month 3 (p = 0.016). No patient in either group experienced severe adverse events. CONCLUSIONS: PDT performed with 50% of the full light dose appears to be a more useful method in the treatment of chronic CSC, with less frequent recurrence, than PDT using 25% of the full light dose.
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Humans , Central Serous Chorioretinopathy , Eye , Follow-Up Studies , Light , Photochemotherapy , Recurrence , Retinaldehyde , Triazenes , Visual AcuityABSTRACT
Background: Melasma is acquired symmetric hypermelanosis characterized by light-to-deep brown pigmentation over cheeks, forehead, upper lip, and nose. Treatment of this condition is difficult and associated with high recurrence rates. With the advent of newer therapies, there is interest in the use of glycolic acid peels and Q-switched Nd:YAG laser (QSNYL) in high and low fluence for this disorder. Aims: To compare the therapeutic efficacy of low fluence QSNYL, high fluence QSNYL, and glycolic acid peel in melasma in three study groups of 25 patients each. Methods: Seventy-five Indian patients diagnosed as melasma were included. These patients were randomly divided in three groups (Group A = 25 patients of melasma treated with low-fluence QSNYL at weekly intervals, Group B = 25 patients of melasma treated with glycolic acid peel at 2 weeks intervals, Group C = 25 patients of melasma treated with high-fluence QSNYL at 2 weeks intervals). Study period and follow-up period was of 12 weeks each. Out of the 75 patients included, 21 patients in Group A, 19 patients in Group B, and 20 patients in Group C completed the study. Response to treatment was assessed using melasma area and severity index score. Results: Significant improvement was recorded in all the three groups. The improvement was statistically highly significant in Group A as compared to Group C (P<0.005), significant in Group A as compared to Group B (P<0.05), and also in Group B when compared to Group C (P<0.05). Low-fluence QSNYL was associated with least side effects. Conclusions: This study shows the efficacy of low-fluence QSNYL and glycolic acid peel in melasma. These could be an effective treatment options compared to conventional methods for the treatment of melasma.
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Choroidal osteoma is an unusual form of intraocular calcification seen in otherwise healthy eyes. It is a benign idiopathic osseous tumor of the choroid, typically seen in young females. Choroidal neovascular membrane (CNVM) is a complication seen in one-third of these patients and carries a poor visual outcome. We report a case of a 25-year-old hyperthyroid female with choroidal osteoma and subfoveal CNVM in her left eye which was successfully treated using low-fluence photodynamic therapy (PDT) with verteporfin followed by a single injection of intravitreal ranibizumab.
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Adult , ANTIBODIES, MONOCLONAL, HUMANIZED ADMINISTRATION & , Bone Neoplasms/complications , Bone Neoplasms/diagnosis , Bone Neoplasms/drug therapy , Choroid Neoplasms/complications , Choroid Neoplasms/diagnosis , Choroid Neoplasms/drug therapy , Choroidal Neovascularization/diagnosis , Choroidal Neovascularization/drug therapy , Choroidal Neovascularization/etiology , Diagnosis, Differential , Female , Follow-Up Studies , Humans , Intravitreal Injections , Microscopy, Acoustic , Osteoma/complications , Osteoma/diagnosis , Osteoma/drug therapy , Photochemotherapy/methods , Tomography, Optical Coherence , Visual AcuityABSTRACT
The Epiphyllum phyllanthus seeds present high sensitivity to light and their germination can be promoted by dim green safe light through the very low fluence response mediated by phytochrome A. Part of seed population have phytochrome B in active form (Pfr) enough to promote germination in darkness. Seeds of Epiphyllum phyllanthus germinate in a wide temperature range from 10 to 40°C, reaching complete germination in the range of 15 to 30°C. Above 35°C the germination rate increases indicating control by a non phytochrome related process. The analysis of kinetics of seed germination indicated that the phytochrome A control is less dependent on temperature than phytochrome B controlled process.
As sementes de Epiphyllum phyllanthus apresentam alta sensibilidade à luz e a sua germinação pode ser promovida pela luz verde de segurança por meio da resposta de fluência muito baixa mediada pelo fitocromo A. Parte da população de sementes tem fitocromo B na forma ativa (Fve) suficiente para promover a germinação no escuro. Sementes de Epiphyllum phyllanthus germinam em uma ampla faixa de temperatura de 10 a 40°C, atingindo germinação completa na faixa de 15 a 30°C. Acima de 35°C a velocidade de germinação aumenta indicando o controle por um processo não relacionado com o fitocromo. A análise da cinética da germinação de sementes indicou que o controle pelo fitocromo A é menos dependente da temperatura do que o processo controlado pelo fitocromo B.
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In proton therapy, the analysis of secondary particles is important due to delivered dose outside the target volume and thus increased potential risk for the development of secondary cancer. The purpose of this study is to analyze the influence of secondary particles from proton beams on fluence and energy deposition in the presence of inhomogeneous material by using Geant4 simulation toolkit. The inhomogeneity was modeled with the condition that the adipose tissue, bone and lung equivalent slab with thickness of 2 cm were inserted at 30% (Plateau region) and 80% (Bragg peak region) dose points of maximum dose in Bragg curve. The energy of proton was varied with 100, 130, 160 and 190 MeV for energy dependency. The results for secondary particles were presented for the fluence and deposited energy of secondary particles at inhomogeneous condition. Our study demonstrates that the fluence of secondary particles is neither influenced insertion of inhomogeneties nor the energy of initial proton, while there is a little effect by material density. The deposited energy of secondary particles has a difference in the position placed inhomogeneous materials. In the Plateau region, deposited energy of secondary particles mostly depends on the density of inserted materials. Deposited energy in the Bragg region, in otherwise, is influenced by both density of inserted material and initial energy of proton beams. Our results suggest a possibility of prediction about the distribution of secondary particles within complex heterogeneity.
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Adipose Tissue , Dependency, Psychological , Lung , Population Characteristics , Proton Therapy , ProtonsABSTRACT
BACKGROUND: Viral warts are benign epithelial proliferations induced by the human papillomavirus (HPV) and they affect 7~10% of the population. Some warts such as periungual warts are resistant to various treatment modalities, including cryotherapy, surgical excision, carbon dioxide laser therapy and immune therapy. Thus, some studies have reported that pulsed dye laser has been effectively used for treating recalcitrant warts. OBJECTIVE: The purpose of this study was to evaluate the therapeutic response and safety of pulsed dye laser using high fluence for the treatment of periungual warts. METHODS: 66 periungual warts on 28 patients were treated with pulsed dye laser. The treatment parameters were a spot size of 5.0 mm, a pulse duration of 0.45~1.5 ms and a fluence of 14.0~15.0 J/cm2. The warts were evaluated at 2~3 week intervals to assess the clearance rate and side effects. RESULTS: Complete clearance was achieved for 47 out of 66 periungual warts (71.2%). The average number of treatment sessions was 2 (range: 1~6). After the first session, complete clearance was achieved for 24 out of 66 warts (36.4%). No significant side effects were observed except for pain during and after the procedure. During a median follow up period of 7 months (range: 3~15 months), 10 periungual warts on 3 patients recurred. CONCLUSION: Pulsed dye laser using high fluence could be used as a safe and successful treatment for recalcitrant periungual warts.
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Humans , Cryotherapy , Follow-Up Studies , Lasers, Dye , Lasers, Gas , WartsABSTRACT
PURPOSE: To evaluate the clinical results of half-fluence photodynamic therapy (PDT) using verteporfin in patients with chronic central serous chorioretinopathy (CSC). METHODS: The author reviewed the charts of 20 patients (22 eyes) who underwent PDT for chronic central serous chorioretinopathy. All 22 eyes were treated using an irradiance of 300 mW over 83 second (25 J/cm2). Postoperative evaluation included improvements in visual acuity, complications, changes in central macular thickness with the optical coherence tomogram (OCT), and recurrence. RESULTS: The best-corrected visual acuity improved significantly from 0.50+/-0.32 to 0.12+/-0.19 logMAR at 3 months (p<0.01), and the mean central macular thickness decreased from 377.7+/-86.3 micrometer to 166.2+/-29.3 micrometer at 3 months (p<0.01). Exudative serous macular detachments were resolved completely in all eyes within 3 months. There was no recurrence after PDT during the follow-up period. CONCLUSIONS: PDT using half fluence appeared to be a beneficial treatment option for patients with chronic CSC. Further studies are needed to verify treatment safety as well as the time and rate of recurrences.
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Humans , Central Serous Chorioretinopathy , Eye , Follow-Up Studies , Photochemotherapy , Porphyrins , Recurrence , Triazenes , Visual AcuityABSTRACT
Objective To develop a measurement method of dosimetric parameters for Hi-ART tomotherapy unit. Methods Percentage depth doses and beam profiles were measured using the dedicated mini water phantom, and compared to the results of 6 MV X-ray from Primus accelerator. Following the AAPM TG51 protocol, absolute dose calibration was carried out under SSD of 85 cm at depth of 1.5 cm for field of 5 cm ×40 cm. The output linearity and reproducibility were evaluated. The output variation with the gantry rotation was also investigated using 0.6 cm3 ion chamber in cylindrical perplex phantom and on-board MVCT detectors. Leaf fluence output factors were quantified for the leaf of interest and its adjacent leaves.Results The buildup depth was around 1.0 cm. The PDD values at 10 cm for Hi-ART and Primus were 59.7% and 64.7%, respectively. Varying with the field width, the lateral and longitudinal beam profiles were not so homogeneous as the Primus fields. The measured dose rate was 848.38 cGy/min. The fitted lint(sec) ,with a relative coefficient of 0. 999. The maximum deviation and standard deviation of output were 1.6% and less than 0.5% ; The maximum deviation and standard deviation of output changed by gantry angle were 1.1% and 0.5 % , respectively. Leaf fluence output factors did not increase significantly when leaves were opened beyond the two adjacent leaves. Conclusions Hi-ART Tomotherapy unit has a very high dose output and inhomogeneous beam profiles owing to its special design of the treatment head. This may be useful in dose calculation and treatment delivery.
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Objective To evaluate the intensity-modulated radiation therapy(IMRT)for the whole pelvis in the treatment for cervix cancer with the method of ionization chamber verification and fluence map verification.Methods IMRT plan was designed with Pinnacle 7.0 inversed treatment planning system,and the planning parameter was copied to the solid water phantom.The dose of the reference points in the phantom was calibrated with ionization chamber,and compared with those in IMRT plan.Then the gantry angle was set as 0 degree.The solid water phantom was irradiated with film,and the actual fluence maps were obtained 2cm below the phantom surface,and then the delivered films were compared with those fluence maps in plan.Results The error percentage at 4 points was less than 3% in absolute dose calibration,at 2 points was less than 5%,at another 2 points was less than 5%,at 1 point was over 10%,and at another 1 point was over 15%.It was found that the last two calibrated points were set in a region with a high dose gradient,resulting in high error.In fact they were impertinent.So another two points were chosen in uniformity area of dose distribution.The percentage of error were both less than 3%.The fluence maps between films and plan were consistent.Conclusion It is feasible to evaluate IMRT plan for whole pelvis in the treatment of cervix cancer with the method of ionization chamber verification and fluence map verification.The results can meet the clinical requirement.