Design and testing of indigenous cost effective three dimensional radiation field analyser (3D RFA).

The aim of the study is to design and validate an indigenous three dimensional Radiation Field Analyser (3D RFA). The feed system made for X, Y and Z axis movements is of lead screw with deep ball bearing mechanism made up of stain less steel driven by stepper motors with accuracy less than 0.5 mm. The telescopic column lifting unit was designed using linear actuation technology for lifting the water phantom. The acrylic phantom with dimensions of 800 x 750 x 570 mm was made with thickness of 15 mm. The software was developed in visual basic programming language, classified into two types, viz. beam analyzer software and beam acquisition software. The premeasurement checks were performed as per TG 106 recommendations. The physical parameters of photon PDDs such as Dmax, D10, D20 and Quality Index (QI), and the electron PDDs such as R50, Rp, E0, Epo and X-ray contamination values can be obtained instantaneously by using the developed RFA system. Also the results for profile data such as field size, central axis deviation, penumbra, flatness and symmetry calculated according to various protocols can be obtained for both photon and electron beams. The result of PDDs for photon beams were compared with BJR25 supplement values and the profile data were compared with TG 40 recommendation. The results were in agreement with standard protocols.

Comparison of Kodak EDR2 and Gafchromic EBT film for intensity-modulated radiation therapy dose distribution verification.

The quantitative dose validation of intensity-modulated radiation therapy (IMRT) plans require 2-dimensional (2D) high-resolution dosimetry systems with uniform response over its sensitive region. The present work deals with clinical use of commercially available self-developing Radio Chromic Film, Gafchromic EBT film, for IMRT dose verification. Dose response curves were generated for the films using a VXR-16 film scanner. The results obtained with EBT films were compared with the results of Kodak extended dose range 2 (EDR2) films. The EBT film had a linear response between the dose range of 0 to 600 cGy. The dose-related characteristics of the EBT film, such as post irradiation color growth with time, film uniformity, and effect of scanning orientation, were studied. There was up to 8.6% increase in the color density between 2 to 40 hours after irradiation. There was a considerable variation, up to 8.5%, in the film uniformity over its sensitive region. The quantitative differences between calculated and measured dose distributions were analyzed using DTA and Gamma index with the tolerance of 3% dose difference and 3-mm distance agreement. The EDR2 films showed consistent results with the calculated dose distributions, whereas the results obtained using EBT were inconsistent. The variation in the film uniformity limits the use of EBT film for conventional large-field IMRT verification. For IMRT of smaller field sizes (4.5 x 4.5 cm), the results obtained with EBT were comparable with results of EDR2 films.

Evaluation of gafchromic EBT film for intensity modulated radiation therapy dose distribution verification.

This work was undertaken with the intention of investigating the possibility of clinical use of commercially available self-developing radiochromic film - Gafchromic EBT film - for IMRT dose verification. The dose response curves were generated for the films using VXR-16 film scanner. The results obtained with EBT films were compared with the results of Kodak EDR2 films. It was found that the EBT film has a linear response between the dose ranges of 0 and 600 cGy. The dose-related characteristics of the EBT film, like post-irradiation color growth with time, film uniformity and effect of scanning orientation, were studied. There is up to 8.6% increase in the color density between 2 and 40 h after irradiation. There was a considerable variation, up to 8.5%, in the film uniformity over its sensitive region. The quantitative difference between calculated and measured dose distributions was analyzed using Gamma index with the tolerance of 3% dose difference and 3 mm distance agreement. EDR2 films showed good and consistent results with the calculated dose distribution, whereas the results obtained using EBT were inconsistent. The variation in the film uniformity limits the use of EBT film for conventional large field IMRT verification. For IMRT of smaller field size (4.5 × 4.5 cm), the results obtained with EBT were comparable with results of EDR2 films.

Vitamin B12 deficiency: a clinical and electrophysiological profile.

OBJECTIVE: The present study was conducted to evaluate the clinical and electrophysiological profile of vitamin B12 deficiency syndrome and whether a correlation exists between the disease process and the various electrophysiological parameters. METHODS: 40 patients with vitamin B12 deficiency neurological syndromes with low serum vitamin B12 and high homocysteine levels were subjected to a detailed motor and sensory nerve conduction studies and pattern reversal VER (P100), SSEP (P37) after stimulation of the posterior tibial nerve and median nerve (N 20) were obtained bilaterally. MR cervical spine was done in all the patients and MR brain in those who presented with neuro-psychiatric symptoms. The patients were followed up at three months, six months and one year after treatment. RESULTS: On the basis of clinico-electrophysiological profile, 31 patients had myeloneuropathy, 5 isolated myelopathy, 4 isolated neuropathy. Four of the patients with myeloneuropathy, had concomitant dementia. MR imaging revealed abnormality in 12.5% of cases. Prolongation of P37 latency was observed in 39 (97.5%) patients, N 20 latency in 22 (55%), and P100 latency in 19 (47.5%) patients. Peripheral neuropathy was seen in 18 patients; optic neuropathy in 8; and combination of peripheral and optic neuropathy in 9 patients. The peripheral neuropathy was axonal in 19, and demyelinating in 6 patients. There was a significant correlation of the duration of the disease with N 20 latency (P < 0.04). Serum vitamin B12 level correlated well with the latencies of P37 (P < 0.005) and sural SNAP (P < 0.006). On treatment, normalization of P100, MRI signal, N 20 and partial recovery of P37 latencies was seen at 6 months, 9 months and one year respectively. CONCLUSION: Differential recovery of central and peripheral syndromes was seen. This correlated with the underlying demyelinating and axonal processes, which was well reflected by the electrophysiological studies, and has an important bearing on the outcome.

Brachial plexopathy: a clinical and electrophysiological study.

BACKGROUND: A retrospective study to evaluate the clinical and electrophysiological profile of brachial plexus lesions in a tertiary care center of India. METHODS: Thirty eight patients with brachial plexopathy (idiopathic or traumatic) with detailed electrophysiological studies were sampled. This included detailed motor and sensory nerve conduction studies of the conventional median, ulnar and radial nerves of the upper limbs, CMAP from deltoid, biceps and triceps on stimulating the ERB's point, needle EMG in the appropriate muscles and paraspinal muscles. The electrophysiological studies were performed on both sides irrespective of the clinical involvement and were recorded within 1.61 +/- 2.89 months in idiopathic group and 2.11 +/- 2.65 months in traumatic plexopathy group. The severity of involvement was assessed on MRC scale. ADL scale was used to assess the disability at presentation and subsequent follow up. RESULTS: 12 patients (11 male and 01 female) had idiopathic brachial plexopathy and 26 patients (all male) had traumatic brachial plexopathy. In the idiopathic group the lesion was localized to upper trunk in 58.3% of patients and middle trunk (posterior cord) in 41.66% and none had lower trunk or diffuse involvement. 25% had bilateral involvement. Two patients (16.6%) with idiopathic plexitis had recurrence involving the opposite side during the follow up. In the traumatic group the lesion was localized to the upper trunk in 11.53%, middle trunk (posterior cord) in 57.69% and 30.76% of patients had diffuse involvement. All the patients in traumatic plexopathy group had severe disability while in idiopathic group 91.66% had severe disability and 8.33% had moderate disability. Low amplitude CMAP and F wave abnormality were seen in 16.6% of patients in idiopathic group. On needle EMG 83.3% had fasciculation or fibrillations while none had paraspinal EMG abnormality. In traumatic group low to absent CMAP was seen in 69.2% and 76.92% had F wave abnormality. SNAPs were not recordable in 53.8%. On Needle EMG all the patients showed fasciculation or fibrillations and only 6 (23.0%) had paraspinal muscle fibrillations. Root avulsion could be documented in only four of these cases on MR imaging. CONCLUSIONS: Recovery in the traumatic group correlated well with the electrophysiological abnormalities while no such correlation was evident in the idiopathic group.

Transperineal low-dose rate iridium-192 interstitial brachytherapy in cervical carcinoma stage IIB.

PURPOSE: To assess local control, survival and complications in patients with cervical carcinoma Stage IIB treated radically with transperineal Iridium-192 low-dose rate interstitial brachytherapy following external beam radiotherapy. PATIENTS AND METHODS: 65 women (age 25-70 years, mean 47 years) with cervical carcinoma Stage IIB were initially treated with external beam radiotherapy on a telecobalt or 6 MV linear accelerator to a dose of 50 Gy delivered in 5-6 weeks. After 2-3 weeks of completing external radiation, patients received interstitial brachytherapy with Iridium-192 (activity 0.5-1 mCi/cm) using a Syed-Neblett perineal template. The median dose delivered to the implant volume was 24 Gy (range 20-32 Gy) delivered at an average dose rate of 0.70 Gy/h (range 0.40-1.20 Gy/h). A point defined at 1.5 cm lateral to the central uterine tandem at the level of os was taken as a representative for assessing the dose to the cervix. Mean doses delivered by interstitial brachytherapy to point A, cervix, point B and rectum were 38 Gy, 34 Gy, 16 Gy and 16 Gy, respectively. RESULTS: At a median follow-up of 53 months, the actuarial disease free survival and overall survival for 65 patients at both 5 and 10 years was 64% and 44%, respectively. Response to radiotherapy was a strong predictor of local control with 82% of patients continuing to have pelvic control after initial complete response. Overall, nine (14%) patients had persistent disease, ten (15%) developed a central recurrence after initial control and three patients developed distant metastasis on follow-up. No patient had any immediate treatment-related complication. Late toxicity included grade I-II rectal reactions in five patients and grade IV bladder complication (vesico-vaginal fistula) in two patients. 5 years after treatment, one patient developed intestinal obstruction, which was relieved after conservative management. Two patients developed vaginal stenosis. The 5- and 10-year disease free survival was 48% in patients aged less than 45 years as compared to 80% in patients of more than 45 years (p = 0.009). Dose to the cervical point was a prognostic indicator with 5- and 10-year disease free survival of 47% in patients who received < 35 Gy in comparison to 80% in patients who had > 35 Gy (p = 0.03). There was no difference in local control and survival in patients with minimal and moderate parametrial involvement. Bulky disease (> 4 cm) at presentation and a longer gap between external radiation and brachytherapy showed a trend towards inferior local control. CONCLUSIONS: Interstitial brachytherapy after external beam irradiation in patients with cervical carcinoma Stage IIB results in acceptable local control, survival and complication rates. Increased dose to the cervical disease results in improved local control and survival and should therefore be considered while optimizing brachytherapy treatment plans. Comparison of the results with those of standard intracavitary therapy remains to be proven in a randomized trial.

Creutzfeldt-Jakob disease : report of 10 cases from North India.

Creutzfeldt-Jakob disease (CJD) is increasingly being reported over the last three decades as a result of heightened awareness of the disease. Various studies have reported annual incidence of 0.5-1.5 cases of CJD per million of general population. In India, the disease is still under reported. Over the period spanning from 1968-1997, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore recorded 69 cases of CJD from different parts of India in the CJD registry. This paper describes the clinical experience with cases of CJD managed at the Department of Neurology, G.B. Pant Hospital, New Delhi from 1990-1998. In this series, the mean age of the patients was 53.80 (+/- 7.32) years and there were 5 females and 5 males. Myoclonus was present in all the cases and abnormal behaviour with or without other features was the presenting complaint in 7 of the 10 patients, while one patient of CJD had cerebellar ataxia as the presenting feature. One patient with occipital variant of CJD presented with acute onset cortical blindness and myoclonic jerks. One of the patients had acute psychosis precipitated by emotional stress at the onset. Extrapyramidal features were noted in 7 of the 10 patients before death. The mean duration of symptoms from the onset of disease to death was 6.6 (+/- 6.11) months. Classical EEG changes were observed in all the patients, except in one possible case of occipital variant of CJD, where we did not have access to EEG record. Brain biopsy could be undertaken in 3 patients, and in 2 patients the features of subacute spongiform encephalopathy (SSE) were noted.

Late esophageal toxicity using a combination of external beam radiation, intraluminal brachytherapy and 5-fluorouracil infusion in carcinoma of the esophagus.

One hundred patients with potentially curable squamous cell carcinoma of the esophagus were treated using a combination of external beam radiation, medium-dose intraluminal brachytherapy (ILBT), and 5-fluorouracil infusion (as a radiosensitizer) from January 1990 to December 1993. The main objective was to determine late toxicity and optimization of the dose of intraluminal radiation. All patients had external radiation of 50 Gy over 5 1/2 weeks, followed by ILBT of 20 Gy for 50 patients (group 1) and 15 Gy for a subsequent 50 patients (group 2), using a dose rate of 315-330 cGy/h with the prescription at 1 cm off axis. The 5-fluorouracil infusion was 500 mg/m2 administered 12 h prior to ILBT. The treatment-related complications among groups 1 and 2 were strictures 24% vs. 8% (p = 0.029), ulceration 30% vs. 28% (p = 0.8), and tracheoesophageal fistulae 12% for both groups. The overall survival for groups 1 and 2 was 8% and 23% at 5 years. The development of life-threatening complications is a major concern and extreme caution is urged before selecting patients for a combination of ILBT and 5-fluorouracil treatment.

Treatment volume from total reference air kerma (TRAK) in intracavitory applications and its comparison with ICRU reference volume.

PURPOSE: A systematic dosimetry study conforming to International Commission on Radiation Units and Measurements Report Number 38, was carried out for, cancer of Cervix Stage I and II cases at Tata Memorial Hospital. METHODS AND MATERIALS: The reference Volume dimension were noted for each applicator. Also 3-D dosimetry was performed for selected cases, and actual geometric volume enclosed by various isodose surfaces were obtained. A relation was derived, which gave the volume enclosed by any isodose surface as a function of total reference air kerma of the sources in the applicator. The volume enclosed by reference isodose surface was compared with the product of its dimensions height, width, and thickness. RESULTS: The volume enclosed by any isodose surface of an intracavitary application can be easily derived from total reference air kerma of the sources within the applicator. CONCLUSION: Ratio of the volume enclosed by reference isodose surface with the product of its dimensions (HWT) could be a predictive parameter for clinical outcome, besides the reference volume specified by the report.

A double-blind evaluation of alprazolam and imipramine in the treatment of major depression.

This report describes the results of a multicentre collaborative study comparing the safety and efficacy of alprazolam with imipramine in patients suffering from major depressive disorder. Two hundred and eight patients diagnosed as major depression as per DSM-III criteria were randomly allocated to alprazolam (N= 105) or imipramine (N = 103) in a double-blind fashion. Detailed assessments were carried out for a period of six weeks. Results revealed that alprazolam was as effective as imipramine as an antidepressant. Side effects were less frequently reported with alprazolam.

Paramedian diencephalic syndrome. Report of 3 cases.

We report three patients who lapsed into coma and subsequently manifested hypersomnolence, amnesia and vertical gaze paresis. Computed tomography revealed bilateral paramedian thalamic infarcts. This clinical symptomatology comprises the paramedian diencephalic syndrome.