Improved lung dose calculation using tissue-maximum ratios in the Batho correction

Journal Article · · Med. Phys.; (United States)

DOI:https://doi.org/10.1118/1.595495· OSTI ID:6340654

El-Khatib, E; Battista, J J

The Batho power law has been reexamined for computing the dose within and beyond lung irradiated with small and large fields of cobalt-60 and 6-MV x rays. Using slab phantoms consisting of two materials, agreement between calculated and measured doses was within 2% inside lung for 6-MV x irradiation, but much poorer (9%) for cobalt-60 irradiation. For cobalt-60 irradiation, tissue-air ratios (TARs) were used initially in the Batho equation, while for 6-MV x rays, tissue-maximum ratios (TMRs) were used. When TMR values were substitutedinstead of TAR values for cobalt-60, marked improvement we found in the accuracy of dose calculated within lung. This was confirmed by numerical comparison of the Batho expression with an analytic solution of th dose calculated within lung. This was confirmed by numerical comparison of the Batho expression with an analytic solution of the primary and first-scattered radiation. The use of TMRs is encouraged for cobalt-60 radiation, especially for larger radiation fields. Measured data tables are provided for field sizes up to 50 X 50 cm2, and depths up to 30 cm. In addition to unifying the dosimetry for all megavoltage irradiation, this approach improves the accuracy of doses calculated within lung.

• Research Organization: Cross Cancer Inst., Edmonton, Alberta, Canada
• OSTI ID: 6340654
• Journal Information: Med. Phys.; (United States), Journal Name: Med. Phys.; (United States) Vol. 11:3; ISSN MPHYA
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
655003* -- Medical Physics-- Dosimetry
ANALYTICAL SOLUTION
BACKSCATTERING
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
COBALT 60
COBALT ISOTOPES
DATA
DOSES
DOSIMETRY
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
GAMMA DOSIMETRY
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LUNGS
MEDICINE
MINUTES LIVING RADIOISOTOPES
MOCKUP
NUCLEAR MEDICINE
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANS
PHANTOMS
RADIATION DOSES
RADIATIONS
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
RESPIRATORY SYSTEM
SCATTERING
STRUCTURAL MODELS
THERAPY
X RADIATION
X-RAY DOSIMETRY
YEARS LIVING RADIOISOTOPES