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Introduction Orthodontic diagnosis and treatment planning encounter distinctive complexities when dealing with cleft lip and palate anomalies. This research endeavors to thoroughly examine skeletal and dental characteristics through cephalometric analyses among individuals with bilateral cleft lip and palate (BCLP) within the central Indian population. Due to anatomical variations and growth constraints, traditional cephalometric mean values derived from standard population studies are often inadequate for these cases. Advanced technology, such as NemoCeph (Nemotech, Madrid, Spain) software, enhances measurement accuracy. Methods Fifty patients, including 25 with BCLP and 25 without BCLP, aged 10 to 18, were selected for this cross-sectional study. Lateral cephalograms were traced and analyzed using NemoCeph software. Skeletal and dental parameters were measured, and a comparison was made between BCLP patients and the general population. Statistical analysis was conducted using the Student's unpaired t-test. Both SPSS Statistics Version 24.0 (IBM Corp., Armonk, NY, USA) and GraphPad Prism Version 7.0 (GraphPad Software, San Diego, CA, USA) were used for data analysis. Results The investigation revealed significant disparities across several parameters, including sella-nasion-A point angle (SNA), sella-nasion-B point angle (SNB), A point-nasion-B point angle (ANB), the inter-incisal angle (the angle between the long axes of the upper and lower incisors), and UP 1 to A-pog (a specific vertical measurement between anatomical markers labeled "upper 1" and "A point to pogonion"), with associated p-values for the skeletal and dental parameters of 0.310, 0.259, 0.195, 0.0001, and 0.0001, respectively. A comparison between manual tracing and digital methods indicated a reduction in errors and an improvement in measurement precision. Notably, patients diagnosed with BCLP exhibited distinctive skeletal and dental traits, highlighting the necessity for tailored treatment approaches. Conclusion This study emphasizes the importance of personalized cephalometric evaluations for patients with BCLP. Standard mean values may not be applicable due to unique anatomical considerations in these cases. Advanced technology and patient-specific assessments are crucial for accurate diagnosis, treatment planning, and orthognathic procedures in individuals with cleft lip and palate conditions. Embracing digital tools and tailored approaches can enhance patient care quality and lead to better clinical outcomes.

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Introduction: points A and B are bony landmarks used in cephalometric studies to assess sagittal ratio between maxilla and mandible. The purpose of this study is to assess the reliability of points A and B as bony landmarks, by investigating the role of incisor repositioning on their cephalometric position. Method: superposition of cephalometric tracings at beginning and end of treatment of 30 patients without bone growth disorders, presenting with biproalveolia and having undergone orthodontic treatment with extraction of four first premolars was carried out to estimate changes in points A and B position. The significance threshold was set at 0.05. Results: our study showed that the influence of orthodontic treatment on point A position was not statistically significant, while its influence on point B position was statistically significant (p= 0,01). Indeed, for every 1mm of incremental repositioning, point B moved back by 0.17mm. Conclusion: incisor repositioning in the mandibular arch induces a change in the position of point B backwards.

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BACKGROUD: To analyze the morphological changes of the anterior alveolar bone after the retraction of incisors in premolar extraction cases and the relationship between incisor retraction and remodeling of the alveolar base represented by points A and B displacements. METHODS: Pre- (T0) and post-treatment (T1) lateral cephalograms of 308 subjects in the maxilla and 154 subjects in the mandible who underwent the orthodontic treatment with extraction of 2 premolars in upper or lower arches were included. Alveolar bone width and height in both the maxillary and mandible incisor area were measured at T0 and T1 respectively. By superimposing the T0 and T1 cephalometric tracings, changes of points A and B, and the movement of the incisors were also measured. Then the correlation between incisor movement and the displacements of points A and B was analyzed. RESULTS: The alveolar bone width (ABW) showed a significant decrease in both maxilla and mandible (P < 0.001) except the labial side of the mandible (P > 0.05). The alveolar bone height (ABH) showed a significant increase in the labial side of maxilla and a significant decrease in the lingual side of maxilla and mandible. A strong positive correlation was verified between incisor movement and position changes of points A and B in both horizontal and vertical directions. CONCLUSIONS: Anterior alveolar bone width and height generally decreased after orthodontic treatment. Incisor retraction led to significant position changes of points A and B. The decrease of anterior alveolar bone due to significant incisor retraction should be taken into account in treatment planning.

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PURPOSE: This study is a comparison between revised Manchester Point A and International Commission on Radiation Units and measurements (ICRU) 89 report-recommended Point A absorbed-dose reporting in intracavitary brachytherapy for patients with cervical carcinoma. METHODS AND MATERIALS: The retrospective dosimetric study is based on the data of 32 patients with cervical carcinoma treated with high-dose-rate brachytherapy. Patients received 21 Gy in three fractions (7.0 Gy X three fractions) to Point A (Aflange, revised Manchester definition). All the patients were replanned with a new Point A (Aicru89) defined on CT images as per the American Brachytherapy Society/ICRU-89. The data collected were compared with the data obtained from Point A (Aflange). RESULTS: When using the Aflange plan normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 820.79 ± 207.47 cGy, 654.66 ± 152.69 cGy, and 588.91 ± 136.35 cGy, respectively. Likewise, when using the ICRU-89 Point Aicru89 normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 869.30 ± 224.67 cGy, 693.24 ± 166.20 cGy, and 616.61 ± 150.32 cGy, respectively. For the rectum, Point Aflange normalization plans, the mean dose of 0.1 cc, 1 cc, and 2 cc volumes was 589.37 ± 163.26 cGy, 487.51 ± 126.03 cGy, and 442.70 ± 111.43 cGy, respectively. Likewise, using the Aicru89 plan, the mean 0.1 cc, 1 cc, and 2 cc rectum volume was 625.07 ± 171.31 cGy, 517.50 ± 131.05 cGy, 464.94 ± 121.81 cGy, respectively. The statistical mean difference of Total Reference Air Kerma rate, V100 (cc), bladder, rectum and sigmoid, was found significant. CONCLUSIONS: It has been found that the position of revised Manchester (Aflange) and ICRU-89 Point A does not match on CT images/radiograph, which resulted in variation in doses to the tumor, V100 (cc), organ at risk, and Total Reference Air Kerma.

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AIM: This study intended to compare the dosimetric parameters using different definitions of prescription point A in high dose rate (HDR) brachytherapy of cervical cancer patients. BACKGROUND: Manchester point A has been widely used for prescribing dose in brachytherapy. However, due to certain limitations of this point, a new definition of point A has been recommended by the American Brachytherapy Society (ABS). MATERIALS AND METHODS: We retrospectively investigated 55 computed tomography-based plans of 20 cervical cancer patients treated with Ir-192-based intracavitary HDR brachytherapy. The dose of 7 Gy in 3 fractions each was prescribed to point A using revised Manchester definition of point A (AMAN) and ABS guideline definition (AABS). The effect of both definitions on various parameters including dose to point A and 90% of tumor volume (D90), dose received by 2cc volume of bladder, rectum and small bowel and treatment volume receiving 100% of prescription dose (V100) was analyzed. RESULTS: Mean percentage difference of point AMAN dose and AABS dose with respect to prescription dose was 1.25% ± 1.43% and 1.21% ± 1.01%, respectively. Mean V100 was 80.4 ± 20.45cc and 88.47 ± 16.78cc for AMAN and AABS plans, respectively, while mean percentage difference between prescribed dose and D90 was found to be -37.90% ± 25.06% and -30.47% ± 25.50% respectively for both the definitions. CONCLUSION: Doses to both Manchester point A and ABS point A may be recorded during the transition period. However, ABS point A can be preferred over the Manchester point A as it conforms better with the desired dosimetric outcome and is found to be more static.

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PURPOSE: To investigate the isodose surface volumes (ISVs) for 85, 75 and 60 Gy EQD2 for locally advanced cervix cancer patients. MATERIALS AND METHODS: 1201 patients accrued in the EMBRACE I study were analysed. External beam radiotherapy (EBRT) with concomitant chemotherapy was followed by MR based image-guided adaptive brachytherapy (MR-IGABT). ISVs were calculated using a predictive model based on Total Reference Air Kerma and compared to Point A-standard loading systems. Influence of fractionation schemes and dose rates was evaluated through comparison of ISVs for α/ß 10 Gy and 3 Gy. RESULTS: Median V85 Gy, V75 Gy and V60 Gy EQD210 were 72 cm3, 100 cm3 and 233 cm3, respectively. Median V85 Gy EQD210 was 23% smaller than in standard 85 Gy prescription to Point A. For small (<25 cm3), intermediate (25-35 cm3) and large (>35 cm3) CTVHR volumes, the V85 Gy was 57 cm3, 70 cm3 and 89 cm3, respectively. In 38% of EMBRACE patients the V85 Gy was similar to standard plans with 75-85 Gy to Point A. 41% of patients had V85 Gy smaller than standard plans receiving 75 Gy at Point A, while 21% of patients had V85 Gy larger than standard plans receiving 85 Gy at Point A. CONCLUSIONS: MR-IGABT and individualized dose prescription during EMBRACE I resulted in improved target dose coverage and decreased ISVs compared to standard plans used with classical Point A based brachytherapy. The ISVs depended strongly on CTVHR volume which demonstrates that dose adaptation was performed per individual tumour size and response during EBRT.

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PURPOSE: External beam radiation therapy (EBRT) and brachytherapy (BT) with concurrent cisplatin is the standard of care for locally advanced cervical cancer. The applicability of image-guided adaptive volume-based high-dose-rate (HDR) intracavitary brachytherapy planning is an active area of investigation. In this study, we examined whether volume-based HDR-BT (HDRVOL) plans leads to more conformal plans compared to Point A (HDRPointA)-based plans. MATERIAL AND METHODS: Two hundred and forty HDRPointA plans from 48 cervical cancer patients treated with chemoradiotherapy were retrospectively collected. Point A plans were renormalized with respect to the high-risk clinical target volume (HR-CTV) for the HDRVOL plans. The doses to organs at risk (OAR; rectum, sigmoid, and bladder), and HR-CTV and the conformal index were compared between HDRPointA and HDRVOL plans. RESULTS: HDRVOL plans resulted in a 6-12% reduction in the total dose (EBRT + HDR-BT) to 0.1 cc, 1.0 cc, and 2.0 cc of the OAR as well as an 8-37% reduction in the dose to 2 cc of OAR per HDR-BT fraction compared to HDRPointA plans. Differences in the conformal indexes between the two groups of plans showed an 18-31% relative increase per HDR-BT fraction for HDRVOL plans. The D90 of the HR-CTV was reduced by 11% by HDRVOL planning and had a median dose of 86 Gy. CONCLUSIONS: Our study reports the relative improvement in OAR doses per HDR-BT fraction by HDRVOL planning compared to HDRPointA planning and demonstrates the dosimetric advantages of volume-based HDR-BT planning in creating more conformal plans.

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PURPOSE: To define the relationship between the Point A prescription dose and the dose delivered to various pelvic lymph node groups during high-dose-rate (HDR) brachytherapy treatment of cervical cancer. In less developed countries, brachytherapy is often done without three-dimensional image guidance, instead relying on plain radiography and prescription to Point A. A defined relationship between Point A dose and lymph node doses would help physicians in these health care settings to more accurately estimate nodal doses. METHODS AND MATERIALS: Treatment data from 50 fractions of HDR brachytherapy of cervical cancer were reviewed, the pelvic lymph nodes were contoured, and dose-volume histogram parameters were obtained. Dose-volume histogram parameters for each contour were normalized as a percentage of the corresponding Point A dose. All nodal groups were divided into left and right sides, except the presacral nodal group. RESULTS AND CONCLUSIONS: Mean Point A doses were bilateral (Bil) 5.92 Gy ± 0.58, left (L) 5.93 ± 0.59, and right (R) 5.92 ± 0.59. Mean normalized D90 values for the various lymph node groups were as follows-obturator: Bil 20.3% ± 4.5, L 20.5% ± 4.4, and R 20.2% ± 5.2; external iliac: Bil 9.5% ± 2.9, L 10.0% ± 3.1, and R 9.5% ± 3.0; internal iliac: Bil 12.2% ± 3.5, L 12.1% ± 3.4, and R 12.9% ± 4.7; common iliac: Bil 4.3% ± 1.6, L 4.3% ± 1.6, and R 4.3% ± 1.7; and presacral: 8.7% ± 3.4. These relationships can serve as a useful tool for evaluating lymph node doses during HDR brachytherapy of cervical cancer in facilities performing two-dimensional treatment planning and those with limited resources.

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PURPOSE: To evaluate the long-term disease control and toxicity to the organs at risk after dose-escalated image-based adaptive brachytherapy (BT) in cervical cancer. METHODS AND MATERIALS: Sixty patients of cervical cancer were treated with external radiotherapy 46 Gy in 23 fractions with weekly cisplatin and MRI-guided BT 7 Gy × 4 fractions with a minimum dose of 85.7 Gy (EQD2) to the high-risk clinical target volume (HRCTV). The BT dose was initially prescribed to point A and plans were optimized to ensure coverage of both point A and HRCTV while maintaining doses to the organs at risk within the recommended constraints. Patients were followed up clinically every three months for the first two years and six months thereafter. Toxicity scoring for urinary and bowel symptoms was done using CTCAE version 3.0. RESULTS: The mean doses to the point A and D90 HRCTV were 85.5 (±2.75) Gy and 98.4 (±9.6) Gy EQD2 respectively. The mean 2 cc EQD2, the bladder, rectum, and sigmoid were 90.6 Gy, 70.2 Gy, and 74.2 Gy respectively. The overall survival at a median followup of 49.8 months was 91.66%. Six (10%) patients developed grade 3 gastrointestinal toxicity. One patient developed grade 3 bladder toxicity. The incidence of bladder, rectal, and sigmoid toxicity increased significantly with doses >85 Gy, 66 Gy, and >71 Gy EQD2 respectively. CONCLUSIONS: While the incidence of grade 3-4 toxicity was low (8.3% for gastrointestinal toxicity and 1.6% for bladder), the threshold for development of grade 1-2 bladder and rectal toxicity was lower than the doses recommended by the GEC-ESTRO group. By adhering to volume-based prescriptions, there is scope of further reduction in toxicity to organs at risk.

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PURPOSE: To evaluate the usefulness of reporting the point A dose in patients with locally advanced cervical cancer treated with image-guided adaptive brachytherapy (IGABT). METHODS AND MATERIALS: Dosimetric data from patients treated with a combination of chemoradiation and intracavitary IGABT were examined in light of their outcomes. Prescribing followed the Groupe Européen de Curiethérapie-European Society for Radiation Oncology recommendations. All doses were converted in 2-Gy equivalent. The relationships between the D90 high-risk clinical target volume (CTVHR) and intermediate-risk clinical target volume (CTVIR) and point A doses were studied. Dose-effect relationships based on the probit model and log-rank test were assessed. RESULTS: Two hundred twelve patients were included with a median followup of 53.0 months. A total of 28 local relapses were reported, resulting in a local control rate of 86.6% at 3 years. Mean D90 CTVHR, CTVIR, and point A doses were: 79.7 ± 10.4 Gy, 67.4 ± 5.8 Gy, and 66.4 ± 5.6 Gy, respectively. The mean D90 were significantly different and independent from the mean point A dose, even in bulky tumors at diagnosis or in large CTVHR lesions. Point A dose appeared correlated with TRAK, and finally with the D90 CTVHR through a complex formula including the CTVHR volume (R2 = 0.55). Whereas significant relationships between the probability of achieving local control and the D90 CTVHR and CTVIR (p = 0.08 and 0.025) were observed, no similar relationship was found with point A dose except a trend of an inverse relation. After sorting patients according to three dose levels, highest local control rates were observed in patients with D90 CTVHR ≥85 Gy, whereas those with point A doses ≥70 Gy had the worst outcomes. CONCLUSIONS: In patients treated with IGABT, point A dose is not predictive of local control but a surrogate of the irradiated volume. Its relationships with the D90 CTVHR are indirect and complex rising the question of relevance of its reporting in routine.

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For tobacco mosaic virus (TMV) as a model virus, this article shows typical issues of scanning soft biological matter by atomic force microscopy (AFM). TMV adsorbed on chemically different flat surfaces, gold, mica, and APDMES-functionalized silicon, is studied in air and aqueous environment. In air, the TMV particles arrangement shows some variety, depending on the substrate. The height of TMV is reduced to 13.7, 15.8, and 15.6 nm, for gold, APDMES, and mica, respectively while the width is about ∼30 nm due to the influence of the tip radius. In aqueous solution, the surface charges of the virus and the solid support play an important role in the virus adsorption process. While deposition on negatively charged mica is favored only at low pH values, it is shown that positively charged APDMES functionalized silicon can be a suitable substrate to work with at neutral pHs. The effects of cantilever oscillation's free amplitude (A0 ) and the amplitude set-point (A) are also assessed here. While high A0 prompt reversible deformation of TMV in measurements performed in air, irreversible damage of the virus in liquid conditions (water) is observed using stiff cantilevers (0.35 N m-1 ) and high A0 (81 nm), leading to a 6 nm reduction in the height of TMV after the first scan. Finally, low values of the amplitude set-point (A/A0 = 0.3), which means applying higher forces to the sample, also brings the damage of TMV virus assemblies, reducing its monolayer roughness to 0.3 nm. Microsc. Res. Tech. 80:18-29, 2017. © 2016 Wiley Periodicals, Inc.

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PURPOSE: To evaluate the dosimetric benefits of MRI-based brachytherapy in small and large high-risk clinical target volume (HR-CTV) in cervical cancer. METHODS AND MATERIALS: Twenty-eight fractions obtained from sixteen cervical cancer patients treated with MRI-based high-dose-rate brachytherapy with standard tandem and ovoid applicators were used; original fractions were optimized to HR-CTV D90. Fractions were separated based on the median volume into small and large (HR-CTV <25 cm3 or >25 cm3) lesion groups. Retrospective plans prescribed to Point A were created for each fraction. D0.1 cc, D2 cc, and International Commission of Radiation Unit and Measurements (ICRU) points were used to compare Point A vs. HR-CTV D90 plans for bladder, rectum, and sigmoid. RESULTS: In the small lesion group, Point A plans vs. HR-CTV D90 plans had significantly higher D0.1 cc, D2 cc, and ICRU points for bladder, rectum, and sigmoid (p < 0.05). In the large lesion group, there was no significant difference between Point A and HR-CTV D90 plans for D0.1 cc, D2 cc, and ICRU points to the organs at risk (OARs). CONCLUSIONS: The dosimetric advantages to OARs offered by MRI-based brachytherapy with prescription to HR-CTV D90 compared to Point A is most distinct for patients with smaller HR-CTV (<25 cm3). This study demonstrates sufficient tumor coverage with lower doses to OARs in HR-CTV D90 vs. Point A plans in the small lesion group. These improvements were not seen in the large lesion group, indicating a lesser dosimetric advantage of HR-CTV D90 compared to Point A planning when the cervical lesion is >25 cm3. Incorporation of interstitial needles for patients with larger HR-CTV is likely the best method to decrease dose to OARs and improve tumor coverage.

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O presente estudo propôs avaliar, cefalometricamente, a alteração do ponto A no plano sagital após mudança na inclinação dos incisivos superiores. Métodos: 21 pares de telerradiografias tomadas, no início e no final do tratamento ortodôntico, foram coletados de uma clínica particular na cidade de Aracaju (SE). A amostra foi dividida em dois grupos, de acordo com a movimentação dos incisivos pós-tratamento: Ipro, onde os incisivos proclinaram (n=12); e Iretro, onde os incisivos retroinclinaram (n=9). O ponto A e a inclinação dos incisivos maxilares foram mensurados em relação às linhas ortogonais formadas pelo plano horizontal de Frankfurt e pelo plano pterigoideo vertical. Todos os dados foram medidos duas vezes, com um intervalo de 15 dias, e as médias foram submetidas ao teste t emparelhado e ao teste de correlação de Pearson. Resultados: quando os incisivos maxilares proclinaram 5,26°, o ponto A retraiu 1,54 mm (r=0,75; p < 0,0001), em uma taxa de 1:3,4 mm/graus. Quando os incisivos maxilares retroinclinaram 5,44º, o ponto A avançou 0,71 mm (r=0,81; p < 0,05), em uma taxa de 1:7,7 mm/graus. Conclusão: o ponto A é influenciado diretamente pela alteração na inclinação dos incisivos superiores e tende a acompanhar o movimento do ápice destes dentes.

This study aims to cephalometrically evaluate the changes at point A on the sagittal plane by measuring dental incisor inclinations before and after treatment. Methods: a total of 21 pairs of pre- and post-treatment lateral cephalograms were collected from a private clinic in Aracaju (SE). The sample was divided into 2 groups according to incisors inclination after treatment: Ipro, proclination after treatment (n=12) and Iretro: retroclination after treatment (n=9). The point A and the maxillary incisor inclinations were measured in relation to the orthogonal lines formed between the Frankfurt horizontal and the pterygoid vertical planes. Data were measured twice within a fifteen day interval, and means were subjected to the paired t and Pearson's correlation tests. Results: when maxillary incisors proclined 5.26° degrees, point A retracted 1.54 mm (r=0.75; p < 0.0001), establishing a ratio of 1:3.4 mm/degrees. When the maxillary incisors retroclined 5.44 degrees, the point A advanced 0.71 mm (r=0.81; p < 0.05), establishing a ratio of 1:7.7 mm/degrees. Conclusion: the point A is directly affected by changes in the upper incisor inclinations and tends to follow the apex movement of these teeth.

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The aim of this retrospective study was to evaluate bony remodelling in the anterior region of the maxilla after bimaxillary surgery for skeletal Class III deformities preoperatively, immediately postoperatively, and 6 months postoperatively. For accurate analysis, cone-beam computed tomographic (CT) images of 29 patients (12 men and 17 women; mean age 22 (range 19 to 44) years) were used. The nasopalatine canal, unaffected by the maxillary Le Fort I osteotomy, was used for the reference points (posterosuperior, midpoint, and posteroinferior). The changes in the distance from each of the points on the nasopalatine canal to the corresponding anterior border of the maxilla were measured and analysed at the 3 stages (p<0.05). Bony resorption was apparent during the postoperative period, and the mean resorption was -1.13 (1.53) mm at the posterosuperior level, -0.92 (0.83) mm at the midpoint, and -0.83 (0.88) mm at the posteroinferior level (p<0.01). These findings show that there had been resorptive remodelling postoperatively in the anterior maxillary region after bimaxillary surgery with superior maxillary movement, which suggests that the postoperative change in the position of point A is affected by operative movement as well as by postoperative relapse and bony remodelling.

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OBJECTIVE: The aim of this study was to evaluate change in the sagittal position of point A due to orthodontic treatment by orthodontic community-cone beam computed tomography (CBCT). MATERIALS AND METHODS: 40 subjects (22 males and 18 females) who had Class II division 2 malocclusion were recruited, and 40 subjects (23 males and 17 females) who had minor crowding in the beginning of the treatment and required no or minimal maxillary anterior tooth movement were served as control. The changes in maxillary incisor inclination, sagittal position of point A, SNA angle, and movement of incisor root apex and incisal edge were calculated before and after CBCT treatment. RESULTS: Maxillary incisors were significantly proclined in the study group but not in the control group. This proclination resulted in 2.95 mm backward movement of the root apex and 6.23 mm forward movement of the incisal edge of maxillary incisors. Point A moved 1.24 mm and 0.18 mm backward in the study and control groups, respectively. Incisor root apex and incisal edge almost remained stable in the control group. No significant change was observed in the SNA angle in both the study and control groups. However, the change in SNA between the two groups was found to be significant. CONCLUSIONS: Proclination of maxillary incisors with backward movement of incisor root apex caused posterior movement of point A. This posterior movement significantly affects the SNA angle.

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Brachytherapy forms an integral part of the radiation therapy in cancer cervix. The dose prescription for intracavitary brachytherapy (ICBT) in cancer cervix is based on Tod and Meredith's point A and has been in practice since 1938. This was proposed at a time when accessibility to imaging technology and dose computation facilities was limited. The concept has been in practice worldwide for more than half a century and has been the fulcrum of all ICBT treatments, strategies and outcome measures. The method is simple and can be adapted by all centres practicing ICBT in cancer cervix. However, with the widespread availability of imaging techniques, clinical use of different dose-rates, availability of a host of applicators fabricated with image compatible materials, radiobiological implications of dose equivalence and its impact on tumour and organs at risk; more and more weight is being laid down on individualised image based brachytherapy. Thus, computed tomography, magnetic-resonance imaging and even positron emission computerized tomography along with brachytherapy treatment planning system are being increasingly adopted with promising outcomes. The present article reviews the evolution of dose prescription concepts in ICBT in cancer cervix and brings forward the need for image based brachytherapy to evaluate clinical outcomes. As is evident, a gradual transition from "point" based brachytherapy to "profile" based image guided brachytherapy is gaining widespread acceptance for dose prescription, reporting and outcome evaluation in the clinical practice of ICBT in cancer cervix.

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We investigated the rectal dose-sparing effect and tumor control of a point A dose-reduced plan in patients with Stage I-II cervical cancer (≤4 cm) arising from a small-sized uterus. Between October 2008 and August 2011, 19 patients with Stage I-II cervical cancer (≤4 cm) were treated with external beam radiotherapy (EBRT) for the pelvis and CT-guided brachytherapy. Seven patients were treated with brachytherapy with standard loading of source-dwell positions and a fraction dose of 6 Gy at point A (conventional brachy-plan). The other 12 patients with a small uterus close to the rectum or small intestine were treated with brachytherapy with a point A dose-reduction to match D2cc of the rectum and <6 Gy as the dose constraint ('point A dose-reduced plan') instead of the 6-Gy plan at point A ('tentative 6-Gy plan'). The total doses from EBRT and brachytherapy were added up and normalized to a biological equivalent dose of 2 Gy per fraction (EQD2). The median doses to the high-risk clinical target volume (HR-CTV) D90 in the conventional brachy-plan, tentative 6-Gy plan and point A dose-reduced plan were 62 GyEQD2, 80 GyEQD2 and 64 GyEQD2, respectively. The median doses of rectal D2cc in the corresponding three plans were 42 GyEQD2, 62 GyEQD2 and 51 GyEQD2, respectively. With a median follow-up period of 35 months, three patients developed Grade-1 late rectal complications and no patients developed local recurrence. Our preliminary results suggested that CT-guided brachytherapy using an individualized point A dose-reduced plan might be useful for reducing late rectal complications while maintaining primary tumor control.

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BACKGROUND: Cephalometrically the position of maxilla is usually assessed by point A, which is one of the most common cephalometric landmarks used for spatial analysis of maxilla, however in certain scenarios we require a alternative landmark. AIMS: In this study a nearest alternative maxillary apical base landmark was identified for Point A substitutions given by different authors. METHODS AND MATERIAL: A cross sectional study was conducted on thirty (30) good quality lateral cephalograms. Only those lateral cephalograms were selected where Point A was easily identified. Landmarks: Sella (S), Nasion (N), Point A and three substitution points Y, L, X were traced. Angles formed by SN with Point A (Angle SNA) and three substitution points (Angle SNY, SNX, SNL) were measured. Correlation of angle SNA with angles SNY, SNX and SNL were derived. Statistical analysis used. RESULTS: Mean and standard deviation for Angles SNA, SNY, SNL and SNX were calculated individually for males and females. 'T' Test was applied to determine statistical significance for all the parameters i.e Age, Angles SNA, SNY, SNL and SNX respectively. Karl Pearson correlation coefficient was carried out to determine the statistical significant correlation for Angle SNA with SNY, SNL and SNX. RESULTS: A mean value of 82.8° ±1.9°, 83.1° ±1.8°, 78.3° ±2.9° and 78.7° ±2.7° for Angle's SNA, SNY, SNL and SNX respectively was observed. A statistically significant correlation was observed between angles SNA & SNY, SNL, SNX & strong positive correlation was observed with angle SNY. CONCLUSIONS: We conclude that Point Y is the most nearing maxillary apical base landmark to Point A. Hence maxillary apical base landmark can be substituted by Point Y where identification of point A is not obvious.

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PURPOSE: To investigate the dosimetric difference due to the different point A definitions in cervical cancer low-dose-rate (LDR) intracavitary brachytherapy. MATERIAL AND METHODS: Twenty CT-based LDR brachytherapy plans of 11 cervical patients were retrospectively reviewed. Two plans with point As following the modified Manchester system which defines point A being 2 cm superior to the cervical os along the tandem and 2 cm lateral (Aos), and the American Brachytherapy Society (ABS) guideline definition in which the point A is 2 cm superior to the vaginal fornices instead of os (Aovoid) were generated. Using the same source strength, two plans prescribed the same dose to Aos and Aovoid. Dosimetric differences between plans including point A dose rate, treatment volume encompassed by the prescription isodose line (TV), and dose rate of 2 cc of the rectum and bladder to the prescription dose were measured. RESULTS: On average Aovoid was 8.9 mm superior to Aos along the tandem direction with a standard deviation of 5.4 mm. With the same source strength and arrangement, Aos dose rate was 19% higher than Aovoid dose rate. The average TV(Aovoid) was 118.0 cc, which was 30% more than the average TV(Aos) of 93.0 cc. D2cc/D(Aprescribe) increased from 51% to 60% for rectum, and increased from 89% and 106% for bladder, if the prescription point changed from Aos to Aovoid. CONCLUSIONS: Different point A definitions lead to significant dose differences. Careful consideration should be given when changing practice from one point A definition to another, to ensure dosimetric and clinical equivalency from the previous clinical experiences.

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PURPOSE: To evaluate whether Point A asymmetry in low dose-rate (LDR) brachytherapy is associated with local control (LC), disease-free survival (DFS) and/or overall survival (OS). MATERIAL AND METHODS: A retrospective analysis of disease control and survival outcomes was conducted for patients who underwent LDR brachytherapy for advanced cervical cancer. Institutional protocol entailed concurrent chemotherapy and whole pelvis radiotherapy (WPRT) over 5 weeks, followed by placement of Fletcher-Suit tandem and colpostat applicators at weeks 6 and 8. Objective Point A doses, 80-85 Gy, were accomplished by placement of Cesium-137 (Cs-137) sources. Cox proportional hazards regression models were used to assess associations between disease control and survival endpoints with variables of interest. RESULTS: The records of 50 patients with FIGO stage IB1-IVA cervical cancer undergoing LDR brachytherapy at our institution were identified. Thirty of these patients had asymmetry > 2.5%, and 11 patients had asymmetry > 5%. At a median survivor follow-up of 20.25 months, 15 patients had experienced disease failure (including 5 cervical/vaginal apex only failures and 2 failures encompassing the local site). Right/left dose asymmetry at Point A was associated with statistically significantly inferior LC (p = 0.035) and inferior DFS (p = 0.011) for patients with mean Point A dose of > 80 Gy. Insufficient evidence existed to conclude an association with OS. CONCLUSIONS: LDR brachytherapy may be associated with clinically significant dose asymmetry. The present study demonstrates that patients with Point A asymmetry have a higher risk of failure for DFS and LC.