Assessment of dose error due to nylon mesh of treatment couch.

PURPOSE: This study aims at the assessment of dose error in patients undergoing radiotherapy due to treatment couch of Co-60 teletherapy unit. MATERIALS AND METHODS: In this study beam attenuation due to treatment couch of Co-60 unit was measured in air for different gantry angles and field sizes. Polymethylmethacrylate (PMMA) phantom was used to estimate the effect of depth on attenuation. Impact of couch on surface dose was also evaluated. RESULTS: Beam attenuation due to couch was in the range of 0.5-28% for different gantry angles with standard field size of 10 × 10 cm(2) with optimum position of metallic cranks. Maximum attenuation (29%) was observed with smallest field size i.e. 5 × 5 cm(2). Beam attenuation has been found higher in phantom as compared to that in air However, no particular trend of attenuation has been noted with varying depth of phantom. A 6% increase in surface dose has also been observed due to couch insertion for normal beam incidence. Maximum error of 80% is also note-worthy for most unfavorable situation of irradiation at 180 degree through the metallic cranks. CONCLUSION: It has been determined that ignoring the treatment couch and its accessories can result in dose error of 0.5-80%, depending on gantry angle, field size and position of couch accessories. Therefore, consideration of dose error due to couch during treatment planning is recommended.

ULTRASOUND--A USEFUL COMPLEMENTARY TOOL TO MAMMOGRAPHY IN ASSESSMENT OF SYMPTOMATIC BREAST DISEASES.

BACKGROUND: Breast cancer is the most common female malignancy worldwide. Pakistan has the highest incidence rate of breast cancer than any other Asian population. The purpose of the study was to evaluate the worth of sono-mammography in diagnosis of symptomatic breast diseases by comparing it with mammogram. METHODS: In this cross-sectional validation study, 45 subjects with mean age of 45 +/- 12.07 were included. Majority of the patients presented with complaint of breast lump. After complete history and clinical examination, all the patients had high resolution ultrasound of bilateral breasts and axilla followed by bilateral mammography. Histopathology was taken as gold standard in this study. The exclusion criteria were pregnancy and patients having direct clinical signs of breast malignancy. RESULTS: Based on histopathology, out of 45 patients with breast symptoms, 12 patients had benign lesions, whereas 32 patients were diagnosed as the cases of breast cancers. Finally one patient did not have biopsy proven final diagnosis. Sensitivity and specificity of ultrasound were calculated to be 100% and 67% as compared to sensitivity and specificity of 90.6% and 91.7% for that of mammography. CONCLUSIONS: Ultrasound is a useful complementary tool to mammography in assessment of symptomatic breast diseases since it helps in characterization and localization of breast lesions seen on mammogram and it is not limited by dense breasts. Also it should be the considered as initial imaging technique for assessment of palpable breast lumps.

Solid neuroendocrine carcinoma of the breast.

Primary neuroendocrine carcinoma of the breast is a rare disease that accounts for less than 5% of all cancers arising from the breast. The tumour cells stain positively for chromogranin and synaptophysin. This report describes the occurrence of infiltrating ductal carcinoma of breast with neuroendocrine differentiated tumour in 37 year old female. Early small cell neuroendocrine cancer of the breast that is treated with surgery and adjuvant chemotherapy shows an increased disease-free survival. She is planned for anthracycline/cyclophosphamide based chemotherapy followed by etoposide/platinum based chemotherapy. As her tumour showed ER/PR positivity, she will be given hormonal therapy subsequently, however, more extensive review is required to define a standard treatment protocol for this rare neoplasm.

Diagnosis and treatment of Hodgkin's lymphoma: at times a challenge.

Hodgkin's lymphoma has been traditionally defined as a hematopoietic neoplasm composed of diagnostic Reed-Sternberg cells. More than 70% of the cases involve cervical or supraclavicular lymph nodes. Isolated sub-diaphragmatic lymphadenopathy or organ involvement is rare. We present the case of Hodgkin's lymphoma in a 51 years old female, who presented with obstructive jaundice and lymphadenopathy, empirically treated previously as a case of tuberculosis. Chemotherapy with modified ABVD protocol was given with dose modification according to LFT's. Her liver functions returned to normal levels after the first cycle. The main purpose of reporting the case is to stress definitive diagnosis of the disease before initiating treatment and the modified chemotherapy regimen used in this infrequent presentation of the disease.

Estimation of absorbed dose to thyroid in patients treated with radiotherapy for various cancers.

This study is aimed at the evaluation of the absorbed dose to the thyroid gland from scattered/primary radiations in patients who have undergone radiotherapy. In this study, the skin entrance dose (SED) on the anterior neck at the level of the thyroid gland was measured using thermoluminescent dosimeters for 57 patients during radiotherapy with (60)Co teletherapy unit. Phantom dosimetry was also performed to find the correlation between the SED and the dose at the depth of the thyroid. SED of patients treated for breast cancer was 6.77±3.49 Gy and that of those with Hodgkin's disease and Ca. lung irradiation were 21.29±13.52 Gy and 28.80±14.94 Gy, respectively. SED at the level of the thyroid gland was found to be highest for patients whose thyroid gland was within the radiation field, while lowest for patients with skull irradiation. Thyroid gland is recommended to be shielded or excluded from the field whenever possible.

Testicular choriocarcinoma: diagnosed on cervical lymph node biopsy.

Choriocarcinoma is a very rare germinal testicular tumour and in literature its incidence has been reported to be 0.3% of all germinal testicular tumours. An important tumour marker is serum beta-hCG which not only helps in establishing diagnosis but also in assessing response to chemotherapy. In this study we present a case of testicular choriocarcinoma, who presented with abdominal pain, cough, generalized weakness and left sided cervical mass. Incisional biopsy of cervical mass was performed. Histopathology revealed metastatic choriocarcinoma. Serum beta-hCG levels were 1227 ng/mL. Patient received intravenous cycles of PEB (cisPlatin, Etoposide, Bleomycin) chemotherapy but he had progressive disease both radiologically and on tumour marker monitoring. He was planned for salvage chemotherapy but was lost to follow up there after. It is concluded that in males, choriocarcinoma carries a very dismal prognosis and a very poor response to chemotherapy and radiotherapy; surgery has no role in the management.

Validation of tuning fork test in stress fractures and its comparison with radionuclide bone scan.

BACKGROUND: Stress fractures are quite common both in athletes and military recruits. The purpose of the study was to evaluate the efficacy of tuning fork in stress fractures by comparing it with three phase bone scan. METHODS: The current study examined 55 subjects whose age ranged 18-28 years. X-rays of all the subjects were unremarkable. After history and clinical examination tuning fork test (TFT) was performed on each case by placing 128 Hertz vibrating tuning fork on the site of pain (underlying bony surface) of tibia or fibula. Each case was scanned using triple phase bone scintigraphy. RESULTS: Fifty-five patients had a total of 67 stress fractures, out of which 53 were picked up by TFT. Sensitivity of TFT was found to be 79% and specificity of 63%. Positive and negative predictive values were 88% and 46% respectively. CONCLUSION: Tuning fork test is a simple and easy approach of diagnosing stress fractures which can be performed even by athletics and military trainers. Management should be initiated in patients who have history of stress related below-knee pain and positive tuning fork test without waiting for bone scintigraphy. For complicated cases the bone scan is the gold standard for diagnosis.