Yi-Jen Chen, MD
Radiation Oncology · Duarte, CANPI 1972698868
Payments from drug & device makers
What this record shows
This record is dominated by consulting fees: $3,750 of the $4,431 with a category attached, or 84.6%. Daiichi Sankyo Inc. accounts for 84.6% of it on its own, with 6 other manufacturers making up the rest. Reporting peaked in 2021 at $3,750 and has fallen 92.8% since, to $270 in 2024.
Across 9 payments — averaging $492.37 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Daiichi Sankyo Inc.$4K
- Accuray Incorporated$214
- Siemens Medical Solutions USA, Inc.$171
- Elekta, Inc.$145
- GT Medical Technologies, Inc$102
- Brainlab, Inc.$39
- plus $10 from 1 others
Across 2 payments — averaging $74,228 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- Merck$113K
- Siemens Medical Solutions USA, Inc.$36K
What the payments were for
- Consulting fees$3,75085%
- Food & beverage$68115%
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| Daiichi Sankyo Inc. | 1 | $3,750 |
| Accuray Incorporated | 2 | $214 |
| Siemens Medical Solutions USA, Inc. | 1 | $171 |
| Elekta, Inc. | 1 | $145 |
| GT Medical Technologies, Inc | 2 | $102 |
| Brainlab, Inc. | 1 | $39 |
| Cequr Corporation | 1 | $10 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
How this compares
$4,431 in reported general payments places this provider in the 80th percentile of 627 radiation oncology providers in California.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Other radiation oncology in Duarte
- Arya AminiDuarte$265K
- Hyun KimDuarte$97K
- Terence WilliamsDuarte$14K
- Rakesh PatelLos Gatos$1.3M
- Amir LavafPalm Springs$411K
- Albert ChangLos Angeles$290K
- Rizwan NuraniApple Valley$220K
- Drew MoghanakiLos Angeles$183K
- Jyoti MayadevSan Diego$170K
- Percy LeeIrvine$125K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.