BACKGROUND: Assuming interinstitutional differences in the treatment of bone metastases, a survey of German radiotherapy institutions was carried out. The goal was to demonstrate regional strategies in pretherapeutic diagnosis, radiation treatment, and follow-up....
This new code of practice for the determination of absorbed dose for x-rays below 300 kV has recently been approved by the IPEMB and introduces the following changes to the previous codes: (i) The determination of absorbed dose is based on the air kerma determination (exposure measurement) method. (ii) An air kerma calibration factor for the ionization chamber is used. (iii) The use of the F (rad/röentgen) conversion factor is abandoned and replaced by the ratio of the mass – energy absorption coefficients of water and air for converting absorbed dose to air to absorbed dose to water. New values for ratios of these coefficients are recommended. Perturbation and other correction factors are incorporated in the equations. (iv) New backscatter factors are recommended. (v) Three separate energy ranges are defined, with specific procedures for each range. These ranges are: (a) 0.5 to 4 mm Cu HVL; for this range calibration at 2 cm depth in water with a thimble ion chamber is recommended. (b) 1.0 to 8.0 mm Al HVL; for this range calibration in air with a cylindrical ion chamber and the use of tabulated values of the backscatter factor are recommended. (c) 0.035 to 1.0 mm Al HVL; for this range calibration on the surface of a phantom with a parallel-plate ionization chamber is recommended.
S C Klevenhagen, R J Aukett, R M Harrison, C Moretti, A E Nahum and K E Rosser
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In the United States, the incidence of skin cancer is greater than that of all other cancers combined, and early diagnosis can be lifesaving. A substantial public health concern, skin cancer is increasingly being diagnosed and managed by primary care physicians. Basal...
A performance assessment was made of the Gulmay D3300 kilovoltage (combined superficial and orthovoltage) X-ray therapy unit. Results are presented for the key dosimetric beam parameters required for routine patient treatment. This unit is relatively new to the UK...
The American Association of Physicists in Medicine (AAPM) presents a new protocol, developed by the Radiation Therapy Committee Task Group 61, for reference dosimetry of low- and medium-energy x rays for radiotherapy and radiobiology math formula It is based on ionization chambers calibrated in air in terms of air kerma. If the point of interest is at or close to the surface, one unified approach over the entire energy range shall be used to determine absorbed dose to water at the surface of a water phantom based on an in-air measurement (the “in-air” method). If the point of interest is at a depth, an in-water measurement at a depth of 2 cm shall be used for tube potentials ⩾100 kV (the “in-phantom” method). The in-phantom method is not recommended for tube potentials <100 kV. Guidelines are provided to determine the dose at other points in water and the dose at the surface of other biological materials of interest. The protocol is based on an up-to-date data set of basic dosimetry parameters, which produce consistent dose values for the two methods recommended. Estimates of uncertainties on the final dose values are also presented.
C M Ma, C W Coffey, L A DeWerd, C Liu, R Nath, S M Seltzer & J P Seuntjens
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PURPOSE: To retrospectively review patterns of failure, cosmesis, and outcomes according to treatment modality of patients with histologically confirmed epithelial skin cancer. METHODS AND MATERIALS: The records of 468 patients having 531 lesions were analyzed; 389...
BCC is a slow-growing, locally invasive malignant epidermal skin tumour which mainly affects Caucasians. BCC tends to infiltrate tissues in a three-dimensional contiguous fashion through the irregular growth of sub-clinical anger-like outgrowths. Metastasis is...
PURPOSE: To evaluate the impact of local superficial radiotherapy with respect to local control, survival, and toxicity for patients with "minimal" stage IA cutaneous T-cell lymphoma (Mycosis Fungoides). METHODS AND MATERIALS: Between 1954 and 1996 a total of 21...
BACKGROUND: Although radiotherapy of skin tumors has lost its former preeminence, there is still need for this modality. The aim of this study was, therefore, to determine the frequency of radiogenic ulcers and tumors following soft x-ray therapy of skin lesions....
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