| Cover | Dec. 11, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Dec. 11, 2024 |
| Entity Registrant Name | QT IMAGING HOLDINGS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-40839 |
| Entity Tax Identification Number | 86-1728920 |
| Entity Address, Address Line One | 3 Hamilton Landing |
| Entity Address, Address Line Two | Suite 160 |
| Entity Address, City or Town | Novato |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94949 |
| City Area Code | 650 |
| Local Phone Number | 276-7040 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.0001 par value |
| Trading Symbol | QTI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001844505 |
