Evaluation of treatment planning system monitor unit calculations for three intensity modulated radiotherapy delivery techniques

We have validated the monitor unit calculations from a commercially available treatment planning system [TPS] for three intensity modulated radiotherapy [IMRT] planning techniques for tangential breast irradiation by using ionization chamber measurements. Treatment plans were generated for forty-two breast patients by a forward planned field in field technique, electronic tissue compensation [ETC], and an inverse planned sliding window technique. We also performed a reproducibility of delivery and dose linearity analysis for each technique. The treatments were delivered to a phantom using a Varian CL21EX linear accelerator. A 2571 0.6 cm3 Farmer type ionization chamber and Farmer 2570/1 electrometer from NE Technology was used to measure output of the linear accelerator and the dose at predefined point in the verification plan. The agreement between the measured and calculated dose was-0.87% +/- 0.54% for field in field technique,-0.74% +/- 0.23% for electronic tissue compensators, and-1.26% +/- 0.48% for the inverse planning technique and. In terms of reproducibility the mean deviation was-1.10% +/- 0.44% for the field in field technique,-0.38% +/- 0.42% for electronic tissue compensators,-1.04% +/- 0.42% for inverse planning technique. Dose linearity experiments showed no significant variations for clinical situations but a breakdown was observed in relative dose for very low monitor units. We have found that the monitor unit calculations for all three planning techniques are correct to the order of 1%, and that the plans can be delivered in a reproducible and accurate manner

Pneumothorax after CT guided transthoracic needle aspiration biopsy of lung masses

The purpose of this study was to analyze the rate of pneumothorax after CT guided transthoracic needle aspiration biopsy [TNAB] of lung masses, using variable needle sizes. A total of 70 patients underwent this procedure, among them, 18 patients [26%] developed pneumothorax with 18G needles 24 patients underwent FNA and seven of them [25%] developed pneumothorax, with 20G needle, 26% developed pneumothorax and with the 22G needle 25% developed Pneumothorax. As a conclusion the study shows that the rate of pneumothorax after CT guided TNAB of lung masses remains almost the same regardless of the size of the needle

Renal transplant complications, role of resistive index on colour doppler ultrasound

We evaluated 50 patients who had renal transplants and were sent for Doppler Ultrasound for complications, after the transplant procedure. Ages of the patients ranged from 20 to 65 years, 39 were male and 11 were female. In inclusions only first month post op patients were included and only those patients were considered who had some sort of complications on ultrasound at some stage of the follow up.Following complications were noticed: Diminished corticomedullary demarcations, increased echogenicity with raised R I [20 pt]. Perinephric collections other than haematoma [13 pt]. Perinephric haematoma [06 pt]. Obstructed transplanted kidney [05 pt]. Diminished arterial vascularity of the kidney [04 pt] Renal vein thrombosis [02 pt]. RI was found to be raised in increased echogenicity, obstructed hydronephrotic kidney, diminished arterial supply and was disturbed in RVT

Doppler evaluation of breast solid masses differentiation of benign and malignant masses role of resistive index

To know the usefulness of color and spectral doppler in evaluation of solid breast masses using vascularity and resistive index. We performed duplex doppler sonography on 100 patients presenting with breast mass. Resistive index and vascularity of the vessels were detected and analyzed and correlated with histopathological results. 70% of the benign lesions were found having ri below 0.8 and 45 out of 50 patients had low vascularity.43 malignant lesions had high vascularity and 80% had ri above 0.8. High flow visualization on power doppler and indicates a higher possibility of malignancy lesions with ri greater than 0.8 gives high probability of malignancy

it aleays DVT? evaluation of leg swelling with color doppler sonography

The aim of this study was to assess the value of duplex ultrasound examination in establishing diagnosis in swollen lower limbs. This study was conducted at the Department of Diagnostic radiology Mayo hospital Lahore. 50 consecutive patients presenting with leg swelling, submitted for colour Doppler sonography of the lower extremities were examined for deep vein thrombosis [DVT]. 46% of the patients were detected as having DVT, when examined through Doppler Ultrasonography. While 28% of the patients were not having any pathology in the limb.26% of the patients were having pathology other than DVT. The veins of the calf muscles are a common site of acute DVT and a source of pulmonary embolism. They should always be investigated in patients with leg swelling. Complete venous evaluation with duplex imaging can be very helpful in determination of underlying cause of the swelling

Umbilical artery doppler flow velocity waveform [FVW] study: Normal vs abnormal

To know the normal umbilical artery waveform pattern and to establish the A/B ratio during the 2nd and 3rd trimester. From this knowledge to detect the abnormal waveform and A/B ratio and its application to diagnose the I.U.G.R. Design: A study of 150 normal and twenty abnormal patients presented through indoor or outdoor basis over a period of about six months. Setting: Department of diagnostic radiology Lahore General Hospital and Park View Clinic, Lahore. Subjects: 150 normal pregnant cases and twenty cases of pregnancy associated with some obstetrical problem from indoor or outdoor. Main outcome measures: Waveform pattern study and A/B ratio calculation. Normal value of A/B ratio decreased from 20th week to 40th week with significant increase in diastolic flow. These normal results were compared with twenty cases of pregnancy associated with some obstetrical problem. Among these three cases were normal, fourteen cases showed reduced diastolic velocity, there showed absent diastolic phase while reverse diastolic phase was not noted in any case which is a sign of severe I.U.G.R. and in these cases A/B ratio was also high as compared to normal cases. Study of pattern of umbilical artery Doppler flow velocity waveform and from it calculation of A/B ratio is very helpful in detecting the cases of I.U.G.R and is also helpful in deciding the time and mode of delivery depending upon the severity of I.U.G.R