Implant positioning in total hip arthroplasty: influence of horizontal and vertical offset on functionality of prosthetic hip joint.

PURPOSE: To analyze the effect of implant position measured in terms of offset on patient reported outcomes (PRO) following hip arthroplasty (THA). METHODS: A total of 243 patients of the total hip replacement who had a one year follow-up were included in the study. Standard both hips radiograph was used to asses post-surgery implant position in terms of horizontal offset and vertical offset, and correlated with functional outcome which was evaluated as change in PRO. i.e., Harris hip score (HHS) post-op. With center of hip rotation as reference, horizontal offset was calculated as sum of distance, of centre, from proximal femoral shaft axis and a vertical line through ipsilateral teardrop, and vertical offset as limb length discrepancy. Post-op patients were classified into three groups depending on the measurement of horizontal offset of the operated hip. The patients having operated hip horizontal offset within 5 mm of the normal hip were grouped as restored offset (RO); those having shorter or higher offset by more than 5 mm compared to normal hip were labeled as decreased (DO) or increased offset (IO) group respectively. The groups were further subdivided into suboptimal and optimal function groups based on HHS, and among these groups, limb length discrepancy was evaluated. RESULTS: Post follow-up mean HHS (78.23 ± 9.96) improved significantly in all three groups (p < 0.0001). The difference in post-operative HHS among DO, RO, and IO groups was significant, with their averages being 72.5 ± 4.7, 82.1 ± 6.5, and 75.2 ± 4.8 respectively (p = .01). Limb length discrepancy was significantly more common in patients with suboptimal functional scores in all three groups. CONCLUSION: This study concluded that both horizontal offset and vertical offset should be reconstructed in patients operated with unilateral THR due to hip pathology, since both factor demonstrated a comparable additive effect on clinical outcome.

Correlation of maximum dose in PTV and the need for in-hospital supportive care during radiotherapy for H and N cancer patients.

CONTEXT: An objective conformal radiotherapy treatment planning criteria that can predict severity of early effects of radiotherapy would be quite useful in reducing the side effects of radiotherapy thereby improving quality of life for head and neck cancer patients. AIM OF STUDY: Retrospective study aimed at correlating the maximum dose in planning target volume (PTV) with early effects of radiation. MATERIALS AND METHODS: Patients with squamous cell carcinoma of H and N region who received radical radiotherapy and concomitant chemotherapy were retrospectively analyzed for maximum dose in PTV and the requirement of gap during radiotherapy or else hospitalization for supportive care during or up to 1 month after completion of radical radiotherapy. RESULTS: Of a total of 23 patients, 8 patients (34.7%) required a gap of 2-14 days during their treatment. Twelve patients (52.1%) required hospitalization for 1-4 days and 4 patients (17.3%) required hospitalization for supportive care after completion of radiotherapy. The maximum dose in PTV ranged from 105.1% to 132.8% with an average of 112.68%. Subgroup analysis revealed a nonsignificant highest maximum dose of 114.72% in subset of patients requiring gap during radiotherapy (n= 8). CONCLUSION: It was concluded that maximum dose in PTV is a useful predictor of need for inhospital supportive care.

Development and Validation of a MATLAB Software Program for Decoding the Treatment Errors in Real-time Position Management™ Gating-generated Breathing Trace.

INTRODUCTION: The Real-time Position Management™ (RPM) is used as a motion management tool to reduce normal tissue complication. However, no commercial software is available to quantify the "beam-on" errors in RPM-generated breathing traces. This study aimed to develop and validate an in-house-coded MATLAB program to quantify the "beam-on" errors in the breathing trace. MATERIALS AND METHODS: A graphical user interface (GUI) was developed using MATLAB (Matrix Laboratory Ra2016) software. The GUI was validated using two phantoms (Varian-gated phantom and Brainlab ET gating phantom) with three regular motion profiles. Treatment time delay was calculated using regular sinusoidal motion profile. Ten patient's irregular breathing profiles were also analyzed using this GUI. RESULTS: The beam-on comparison between the recorded reference trace and irradiated trace profile was done in two ways: (1) beam-on time error and (2) beam-on displacement error. These errors were ≤1.5% with no statistical difference for phase- and amplitude-based treatments. The predicated amplitude levels of reference phase-based profiles, and the actual amplitude levels of amplitude-based irradiated profiles were almost equal. The average treatment time delay was 47 ± 0.003 ms. The irregular breathing profile analysis showed that the amplitude-based gating treatment was more accurate than phase based. CONCLUSION: The developed GUI gave the same and acceptable results for all regular profiles. These errors were due to the lag time of the linear accelerator with gating treatment. This program can be used as to quantifying the intrafraction "beam-on" errors in breathing trace with both mode of gating techniques for irregular breathing trace, and in addition, it is capable to convert phase-based gating parameters to amplitude-based gating parameters for treatment.

The Composite Planning Technique in Left Sided Breast Cancer Radiotherapy: A Dosimetric Study.

OBJECTIVE: The aim of this retrospective study is to reduce the dose of heart, both lung and opposite breast and left anterior descending artery (LAD) and avoid long term complication and radiation induced secondary malignancies in radiotherapy left breast/chest wall without losing homogeneity and conformity of the Planning Target Volume (PTV), contoured using Radiotherapy Oncology Group (RTOG 1005) guideline. MATERIALS AND METHODS: The treatment plans were generated retrospectively by TFIF, VMAT and Composite techniques for 30 patients. Dose-Volume Histograms (DVHs) were evaluated for PTV and organs at risk (OAR's) and analyzed in two groups BCS and MRM using Wilcoxon signed rank test. RESULTS: The homogeneity index (HI) was improved in Composite technique by 32.72% and 21.81% of VMAT, 50.66% and 49.41% of TFIF in BCS and MRM group respectively. The Conformity Index (CI) for composite plan was statistically same as VMAT and superior by 27.94% and 41.37% of TFIF in BCS and MRM group respectively. The low dose volume V5Gy and V10Gy of the heart were improved in Composite plan by 47.9% and 26.1% of VMAT respectively in BCS group and in MRM group, improved by 21.2% and 45.6% of VMAT. The V5Gy and V10Gy of ipsilateral lung were improved in Composite plan by 16% and 13.7% of VMAT respectively in BCS and 8.4% and 3% of VMAT respectively in MRM group. CONCLUSION: The Composite plan consisting of VMAT and TFIF plan with an optimum selection of fractions can achieve lower low dose exposure to the OAR's without compromising coverage compared to VMAT.