حول تطبيق انظمه الوقاية الاشعاعيه للتعرضات الطبية باستخدام كواشف "الوميض الحرارى"

مدحت شعبان السيد""

"On the implementation of radiation "On the implementation of radiation          

                                                "The study was to assess the risk to all personnel exposed to ionizing radiation during their stay near patients receiving I-131 at the isotopic therapy ward. This study was done at the department of Radiation Oncology and Nuclear Medicine at Ain Shams University and the Radiation Research and Technology Center, Atomic Energy Authority, department of dosimetry & radiation protection. This study included the selection of 23 patients with cancer thyroid. Patient of ages were between 27-57 years. Patients were divided into two groups the ablation group (A) and the follow up group (FU). The ablation group received iodine for the first time .The follow up group received subsequent therapeutic doses for recurrence or metastasis.

This matter requires certain considerations based on accurate measurements of exposures doses recorded at various distances from the patient, and the calculation of the doses received by all other individuals. The purpose is to provide users with consolidated and appropriate information based on the measurements perform. The work includes guidelines for patients and all persons that may receive radiation exposures from patients under treatment, under all circumstances. The implementation of radiation protection guidelines to protect the surroundings of the patient.

        The radiation protection guidelines necessary for radionuclide therapy using I-131 for patient’s relatives, as well as for nursing and hospital staff have been considered.

Dose rate measurements taken from 23 thyroid cancer patients after an individual in contact with a patient may receive radioiodine administration with nursing and social contact times to calculate the cumulative dose. Restrictions to less than 1 mSv. Dose rate decay was biexpotential for receiving radioiodine to ablate the thyroid after surgery and monoexpotential for these receiving subsequent treatments for residual or recurrent disease. The doses to members of the public, with patients undergone therapeutic treatment with unsealed radioiodine, daily measurements of the dose rate on the patient, body surface, subjected to risk of a radiation dose, children and spouses following 4 days of staying in the word, treated is delayed, by 10 – 20 days. After treatment of thyroid cancer with 5550 MBq the delay should be 2–3 days. In the vase of metastases to the bones and lungs, median dose for an ablative patients (0.7, 0.3) mSv. post 2 & 96 hours, median dose for a discharge patients (0.6, 0.2) mSv. post 2 & 96 hours.

   The mean half-life of the dose rate decreased   biexponentially in the       

   ablation patients (A) of the long and short components (±1Std) as follows:

 3.8 (±0.02) + 0.7 (± 0.01) days at the 0.1 meter distance.

1.3 (±0.01)  + 0.3 (±0.02) days at the   0.5 meter distance.

0.9 (± 0.01  + 0.2 (± 0.01) days at the 1.0 meter distance.

      The mean half-life of the dose rate decreased monoexponentially in the follow-up patients (FU) as follows:

          D (t) = D (0) e-λ1t , D (t) = D (0) e-λ2t , D (t) = D (0) e-λ3t

      The mean half-life of the dose rate decay (± 1SD) was  

     74±(0.01) hours at 0.1 meter,

     41±(0.02) hours at 0.5 meter, and

     35±(0.02) hours at 1.0 meter.

Thermo luminescent dosimeters (TLD), given to a number of nurses to reassurance for incurs radiation. The results were obtained:

The Cumulative doses to nursing staff from group (A) ablative patients are (5.3, 3.7, 1.5) mSv per year and from group (FU) follow-up patients are (4, 2.8, 1.1) mSv per year. These dose behavior to limit received doses to less than 20 mSv.

Assessment risk of contamination internal patient undergoing radioactive material the concentration of radioiodine in domestic drainage systems should not post a significant risk."