Abstract:
:We comment on a previous article by Zhang and Newhauser (2009 Phys. Med. Biol. 54 1383-95) which presents several approximate ways of computing the water equivalent of an arbitrary degrader. First, we present a simple exact method which depends only on the range-energy relation of water and of the degrader material. Second, we point out that any theoretical method, approximate or exact, ultimately depends on the range-energy relation, that is to say, the correct value of the mean excitation energy I for the materials in question. Unfortunately I is particularly problematic for water. Therefore, at the present state of knowledge, we should measure water equivalent, rather than computing it, whenever an accurate value is needed.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Gottschalk Bdoi
10.1088/0031-9155/55/9/L01subject
Has Abstractpub_date
2010-05-07 00:00:00pages
L29-30; author reply L31-2issue
9eissn
0031-9155issn
1361-6560pii
S0031-9155(10)14043-5journal_volume
55pub_type
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